Absorption and emission spectral studies of two vinylogous series of cyanine dyes
by Nancy Jane Land Roth
A thesis submitted to. the Graduate Faculty in partial fulfillment of the requirements for the degree
DOCTOR OF PHILOSOPHY in Chemistry
Montana State University
© Copyright by Nancy Jane Land Roth (1971)
Abstract:
The absorption and emission spectra in methanol of the dyes of the 3,3'-diethylthiacyanine iodide series
and of the 3.3.'-diethyloxacyanine iodide series (except for the first member which was the triiodide)
were determined. The integrated intensities and oscillator strengths were calculated. In each series
these quantities increase as the methylene chain length increases. From the absorption and emission
spectra, the radiative lifetimes were calculated by the formula derived by Strickler and Berg as
modified by Birks and Dyson: The lifetimes were of the order of three nanoseconds for the thiacyanine
series and of the order of two nanoseconds for the oxacyanine series. The fluorescence efficiencies
were determined.. They increase by a factor of ten as the chain length, increases except for the. first
member of the sulfur series which is lower by a factor of 100 from the next member. The observable
lifetimes were calculate from the radiative lifetimes and the fluorescence efficiencies. Since the rate of
all decay processes is the inverse of the observable lifetime, a minimum may. be placed on the rate of
energy transfer from the first excited state for these dyes when energy transfer processes take place.
(Formula not captured by OCR) ABSORPTION AND EMISSION SPECTRAL STUDIES OP TWO,
. VTNYLOG-OUS SERIES OF CYANINE DYES
by
NANCY JANE LAND ROTH
-T
A t h e s i s s u b m i tt e d to . t h e G r a d u a te F a c u lt y , i n p a r t i a l
f u l f i l l m e n t o f t h e r e q u i r e m e n ts f o r t h e d e g r e e
of
DOCTOR OF PHILOSOPHY
in
C h e m is try
A u '. £■
H ead , M a jo r D e p a rtm e n t (j
C h a irm a n , .E x a m in in g .. C om m ittee
G r a d u a te Dean
MONTANA STATE UNIVERSITY
Bozem an, M ontana
A u g u s t, 1971
\
ACKNOWLEDGMENTS
The a u t h o r w ould l i k e t o th a n k D r. A rn o ld C. C r a ig
f o r h i s i n v a l u a b l e a i d and d i r e c t i o n d u r i n g t h e c o u rs e
o f t h i s - g r a d u a te s t u d y an d D r; P a t r i k C a l l i s f o r h i s
h e l p w ith t h e n e c e s s a r y i n s t r u m e n t a t i o n .
A l s o , . t h e a u t h o r th a n k s t h e N a t i o n a l S c ie n c e Foun­
d a t i o n a n d M ontana S t a t e U n i v e r s i t y f o r t h e s u p p o r t
o f th is re se a rc h .
F i n a l l y , sh e d e s i r e s to e x p re s s h e r lo v e and g r a t i ­
tu d e t o h e r p a r e n t s , . Mr; an d M rs. R o b e r t J . L an d , and
e s p e c i a l l y t o h e r h u s b a n d , ..Mri „ Jam es W. R o th , f o r t h e i r
c o n ti n u e d e n c o u ra g e m e n t a n d u n d e r s t a n d i n g .
■
:'
■
’
-
.
'
.
- K
,
I
.
- • .■ ' ' '
ill-
.ABSTRACT
The .a b s o r p t i o n and. e m is s io n s p e c t r a i n m e th a n o l
o f th e dyes o f th e 3 , 3 ' - d ie th y lth ia c y a n in e io d id e s e r ie s
an d o f t h e 3 t^ .’.- d i e t h y l o x a c y a n i n e i o d i d e s e r i e s ( e x c e p t
f o r t h e f i r s t member w h ich was t h e t r i i o d i d e ) w ere
d e te r m in e d .
The i n t e g r a t e d i n t e n s i t i e s a n d . o s c i l l a t o r
s t r e n g t h s w ere c a l c u l a t e d .
In each s e r ie s th e s e
q u a n t i t i e s i n c r e a s e a s t h e m e th y le n e c h a in l e n g t h
in c re a s e s .
From t h e a b s o r p t i o n an d e m is s io n s p e c t r a ,
t h e r a d i a t i v e l i f e t i m e s w ere c a l c u l a t e d by t h e fo r m u la
d e r i v e d by S t r i c k l e r a n d B e rg a s m o d if ie d by. B irlc s
an d D yson:
i
= 2 .8 8 0 X 1 0 -9
Lo
nu o -H
mI o iT ^ u
<-io
<4 ; - 3 ) - I
av
;
**
1 1*
16 -»u
Ei
8U
. •
The l i f e t i m e s w ere o f t h e o r d e r o f t h r e e n a n o s e c o n d s
f o r t h e t h i a c y a n i n e s e r i e s an d o f t h e o r d e r o f two
n a n o s e c o n d s f o r t h e o x a c y a n in e s e r i e s .
The f l u o r e s c e n c e
e f f i c i e n c i e s w ere d e te rm in e d .. They i n c r e a s e b y a. f a c t o r
Of t e n a s t h e c h a i n le n g th , i n c r e a s e s e x c e p t f o r th e.
f i r s t 'm e m b e r o f t h e s u l f u r s e r i e s w h ich i s lo w e r by
a f a c t o r o f 100 fro m t h e 'n e x t m em ber. The o b s e r v a b l e
l i f e t i m e s w ere c a l c u l a t e # fro m t h e r a d i a t i v e l i f e t i m e s
an d t h e f l u o r e s c e n c e e f f i c i e n c i e s .
S in c e .th e r a t e o f
a l l decay p ro c e s s e s i s th e in v e r s e o f th e o b s e rv a b le
l i f e t i m e , , a minimum may. b e p l a c e d on t h e . r a t e o f e n e rg y
t r a n s f e r from t h e f i r s t e x c i t e d s t a t e f o r t h e s e d y e s
when e n e rg y t r a n s f e r p r o c e s s e s t a k e p l a c e .
TABLE OF CONTENTS '
INTRODUCTION ^* * * • •••*•, # •RESULTS. AND, DISCUSSION
. SUMMARY
. . . . . . . . .
...
... .
» # # #
....
. ...
. ....
I
. .2 3
. ■...................................... . ........................ 55
EXPERIMENTAL . • . .................................. ....
......
. .
. .56
P r e p a r a t i o n o f 3 ~ E th y l= 12-m ethy:I b e n z o t h ia z o l i u m
Io d id e
. . . . . . . . . . . . . . '. . >. . . . ,. . . .
P r e p a r a t i o n o f 3r E th y l- 2 - m e th y I b e n z p x a z o liu m
I o d i d e J. '*. ( I* • . ■• • . . - . e e 6 . e i . . . . . .
P re p a ra tio n o f l,3 - D le th y l- 2 - m e th y lb e n z im id a z o liu m I o d i d e
......
. . . .
.. .
58
. .
■
. .59
P r e p a r a tio n o f 3 , 3 '-D ie th y lth la c a rb o c y a n in e
Io d id e
60
P r e p a r a t i o n o f 3 ,3 *- D l e t h y l t h i a d i e a r b o e y a n i n e
Io d id e
.................... . . . . . . . . . .
......................... 60
P r e p a r a t i o n o f 3 » 3 ' - D ie th y l o x a c y a n i n e
T riio d id e . . . .
. . . . . . . . .................................. 6 l
P r e p a r a t i o n o f 3 » 3 1- D le .th y lo x a e a r b o e y a n in e
Io d id e *
.
. . ....
.. .
. . 63
P r e p a r a t i o n o f 3 , 3 V - D ie th y lo x a d ie a r b o c y a n in e
Io d id e „ .
. . . . . . ...... . .
. . . . ,. 63
AiBnmple O f'5 3 ,3 8- D i e t h y l t h i a e y a n i n e I o d i d e . . . . .
■ - V
1
64
:
A tte m p te d P r e p a r a t i o n o f I , I ' , 3 , 3 ' T e tir a e th y lb e n z im id a z o lo c a r b o c y a n in e I o d i d e . . . .
BIBLIOGRAPHY ..........................................................
—Vew
. . . . . . . . . .
65
66
LIST OF TABLES
table
i
.. .. .. .. ...
■TABLE LI .....
..
... ...
........
■
table
table
.....
...
.
.
. ..... . . . . . .;j..
. .. .
i v .. . .. .. . .. . . . . . .
. . . .
I . . .
FIGURE
2 . . ....
. . . . . .
.. . .'
FIGURE
3.
.
............................
.
. .
. ...
■. ... .
.. . .
.,
. .■ .
. ...‘
J
FIGURE 4 .;-o
FIGURE
FIGURE '6
5 • ...
. ... e:
^
.
.. ,
...
46
, v-..
LIST OP FIGURES
FIGURE
. . . .3, 8
..............................
i n . ;■>; ; . ... .
TABLE V
; . . . . . 33
-
.' . . ... .
. ..
;.
............ ... .
FIGURE 7 • • ..................................... . . .
. .
FIGURE 8
FIGURE 9 .: . . . .................................. ....
-v i-
.
.. . .. .
. 48
. .
.' 51
INTRODUCTION
A c o l o r f u l > b r l g H t p u r p l e d y e fo rm ed i n s m a ll y i e l d
when A. W, Hofqiann^ i n 1887 r e a c t e d 3 - p e n t y l 'b e n z o t h i a z o l Ium i o d i d e an d 2-* m e th y l-3~ p e n t y l b e n z o th i a z o l i u m i o d i d e
I n t h e p r e s e n c e o f a m m o n i a . -,L ike o t h e r d y e s o f t h e
c y a n in e C l a s s 1 t h i s compound w a s . n o t s t a b l e enough f o r
P
d y e in g t e x t i l e s .
P r e v i o u s l y i n 1 8 7 3 , H. W. V ogel h a d
fo u n d t h a t p h o t o g r a p h i c e m u ls io n s c o u ld b e made s e n s i t i v e
t o c o l o r s o t h e r t h a n b l u e by. b a t h i n g t h e p h o to g r a p h ic
p l a t e s i n a d i l u t e s o l u t i o n o f d y e s su c h a s t h e c y a n i n e s .,
S in c e t h e c y a n in e d y e s i n c l u d i n g t h a t one f i r s t p r e p a r e d
b y Hofm ann w e re fo u n d t o b e u s e f u l f o r s e n s i t i z i n g p h o to ­
g r a p h i c f i l m s , m em bers o f t h i s f a m i ly o f d y e s w ere
s y n t h e s i z e d and c h a r a c t e r i z e d .
H ofm ann’ s dye was fo u n d by W. H, M i l l s -5 t o h a v e t h e
s t r u c t u r e shown i n F i g u r e I w h ere Y = S
an d n - I .
The
common name f o r t h i s d y e i s 3-,3.1- d i e t h y l t h i a c a r b o c y a n i n e
i o d i d e (Dye I I )
w h ile t h e dy e w ith Y = S a n d n = O i s
3 , 3 8- d i e t h y l t h i a c y a n i n e i o d i d e (Dye I ) an d t h e dy e w ith
Y = S and n = 2 i s 3 , 3 d i e t h y l t h ia d ic a r b o c y a n in e i o d i d e
(Dye I I I ) .
T h e re i s a s i m i l a r v in y lo g o u s s e r i e s o f d y e s w here
Y = 0.
The f i r s t member w h ere n - 0 i s 3 - ,.3 .'- d ie th y lo x a -
-2 -
P ig u r e I
c y a n in e i o d i d e
(Dye IV when i o d i d e i s r e p l a c e d b y t r I i o ­
d i d e i o n ) ; t h e s e c o n d w here n = I i s 3 , 3 ' - d i e t h y I o x a c a r b o c y a n in e i o d i d e (Dye V ); and t h e t h i r d w h ere n — 2
i s 3 ,3 * - d l e t h y l o x a d l c a r b o c y a n i n e i o d i d e (Dye V I ) .
A c y a n i n e , s u c h a s t h a t shown i n F ig u r e I ,
is a
m o n o -a c id s a l t i n w h ich t h e n i t r o g e n atom s o f two
h e t e r o c y c l i c r i n g s a r e l i n k e d b y a c h a in o f a l t e r n a t i n g
d o u b le and s i n g l e b o n d s .
S in c e t h i s c h a in c o n s i s t s
o f an odd num ber o f c a rb o n a to m s , t h e two s t r u c t u r e s
a re reso n an ce h y b rid s .
Thus e a c h n i t r o g e n ato m i s
p r o b a b ly b e s t r e p r e s e n t e d as. so m e th in g , b e tw e e n t e r t i a r y
a n d q u a te r n a r y ., an d e a c h b o n d a s so m e th in g b e tw e e n
s i n g l e a n d d o u b le .
A m o le c u le w ith a c o n ju g a te d sy s te m o f t h i s ty p e
m ig h t b e e x p e c te d t o h a v e a r e l a t i v e l y . , s m a ll e n e rg y
d i f f e r e n c e betw een , t h e g ro u n d s t a t e and t h e f i r s t e l e c ­
tr o n ic e x c ite d s t a t e .
T h is h a s b e e n fo u n d t o b e t r u e .
F i s h e r a n d Hamer2f" r e p o r t e d w a v e le n g th s f o r t h e a b s o r p ­
t i o n maxim a o f t h e s i x d y e s:.
557 m
Dye I , 422
Dye I I ,
Dye I I I , 650 t&jlly Dye -IV',.. 372. i n // ; Dye V,
485 mju \ Dye VI., 580 m/Zi.
They a ls o , g a v e t h e q u a l i ­
t a t i v e v i s u a l c o l o r s of. t h e f l u o r e s c e n c e f o r t h e s e
dyes..
H o fe r,. e t
i n 195.0 s t u d i e d t h e m onom eric
f l u o r e s c e n c e of. some o f t h e s e .d y e s a t room te m p e r a t u r e
in g ly c e r o l..
The p o s i t i o n s o f t h e f l u o r e s c e n t maxima
I,1-
w e re d e te r m in e d v i s u a l l y fro m p h o to g r a p h ic p l a t e s .
The m axim a q u o te d w ere th e . f o llo w in g .:
Ii
Dye I , no o b s e r -
v a b le f l u o r e s c e n c e ; Dye I I ., 586/ m / / ; Dye i l l ,
Dye V, 512 DiyUi.
o f E .P..A .
6 91 m /z;
Some w ork was d o n e i n a r i g i d medium
( e t h a n o l - e t h e r - i s o p e n t a n e 2 : 5 ..:. 5) a t 7 7 ° K.
b y M a z z u c a to ,. e t . a l . ^ i n 1964*
T h e i r r e s u l t s w e re 575
mjo . f o r t h e . f l u o r e s c e n c e o f Dye I I under, t h e s e c o n d i t i o n s ,
an d 498 my z f o r Dye V.
-4 -
To m e a su re t h e a b s o r p t i o n s p e c tru m o f a m o le c u le
i n s o l u t i o n , t h e sa m p le i s c o n t a i n e d i n a c e l l o f p a th
l e n g t h ! ...( I n c m .) , a t a c o n c e n t r a t i o n O ( i n g . m o le s
per lite r ) ,
and t h e r a t i o o f t h e t r a n s m i t t e d l i g h t
i n t e n s i t y I t o t h e i n c i d e n t l i g h t i n t e n s i t y I@, i s
d e te r m in e d ..
T h is r a t i o
i s g iv e n a ls o by
lo g JL
Ib
w h ere £
— £ G I
i s c a lle d th e e x tin c tio n c o e f f i c i e n t ( u n its o f
l i t e r moles'""]- cm ." " I).
The maximum v a lu e o f
6
( £ max)
f o r an a b s o r p t i o n b a n d i s . a ro u g h m e a su re o f t h e i n t e n ­
s i t y , o f th e b an d .
H ow ever, a b s o r p t i o n b a n d s f o r m ost
m o le c u le s a r e b r o a d a n d d i f f e r e n t i n s h a p e .
Thus a
b e t t e r , m e a su re o f i n t e n s i t y i s t h e a r e a u n d e r t h e a b ­
s o rp tio n c u r v e ,.th a t i s ,
th e in te g r a te d i n t e n s i t y .
S in c e t h e o s c i l l a t o r s t r e n g t h f i s p r o p o r t i o n a l t o t h e
in te g ra te d in te n s ity ,
th e o s c i l l a t o r s tr e n g th i s g e n e r a l­
ly . c a l c u l a t e d t o com pare t h e i n t e n s i t i e s o f a b s o r p t i o n
batid E . ?
The I n t e n s i t y o f a b s o r p t i o n f o r a t r a n s i t i o n from
a s t a t e o f e n e r g y Bn t o a s t a t e .Effl (w h ere Em, >
En ) may
b e d e f i n e d a s t h e e n e rg y , a b s o r b e d fro m t h e i n c i d e n t
beam o f I c m .^ c r o s s - s e c t i o n p e r u n i t tim e .
I f 'V i s
-5 -
t h e wave num ber i n e m ." l o f t h e i n c i d e n t r a d i a t i o n , a n d
(;D) i s i t s , r a d i a t i o n d e n s ity ;, th e n
la b s .
= / ?
(^ )
% Bab %' * ^
(I)
w h e re Un . i s th e , num ber o f m o le c u le s per-, cm. ^ i n t h e
i n i t i a l s t a t e , , Bnm i s E i n s t e i n ’ s c o e f f i c i e n t o f a b s o r p ­
t i o n , . w h ic h i s a c h a r a c t e r i s t i c . o f t h e m o le c u le , and d I
iS ' th e . t h i c k n e s s o f t h e l a y e r . in . cm.
The q u a n t i t y h .
i s P l a n c k ’ s c o n s t a n t w h ile c i s t h e s p e e d .o f l i g h t .
The i n t e n s i t y of. t h e i n c i d e n t l i g h t , I., w h ic h
i s t h e e n e r g y f a l l i n g on I cm. 2 p e r s e c o n d , c a n b e
g i v e n by
I. -
c y O { ' V) d u
(2)
I f e q u a t i o n ( I ) i s m u l t i p l i e d on b o t h s i d e s b y d zV ,
an d e q u a t i o n ( 2 ) i s s u b s t i t u t e d i n t o e q u a t i o n ( I )
th e n
th e fo llo w in g e q u a tio n i s o b ta in e d :
Ia b B . a Z'
"
I
3r.~ !-• *' a I -
(3 )
When I, p a s s e s th r o u g h a n a b s o rb in g , l a y e r o f
th ic k n e s s d I . th e p a r t o f I a b so rb ed w ill b e p ro p o r­
t i o n a l to b o th I and d I
1 S b s.
such t h a t 1
- =< I d I
(4 )
*°6a
w h ere
i s th e a b s o rp tio n c o e f f i c i e n t .
The a b s o r p t i o n
c o e f f i c i e n t i s r e l a t e d t o t h e m p la r e x t i n c t i o n c o e f f i c i e n t
I■
i n t h e f o llo w in g .w a y :
.I n * 2 ■ = °< I
1.
= -log i 2
■I
■[ I n 10 . ) /
V
/ \
so t h a t
. . I .. ) , ,
2 0 1 /
<=< = 0 .1 0 2 8 6
S u b s t i t u t i o n o f t h e v a lu e o f €
l a b s , ,=
( 5)
i n t o e q u a t i o n (4 ) g iv e s ;
- 0 .1 0 2 8 6 I d I
.
(6 )
If, e q u a t i o n (6,1 i s m u l t i p l i e d on b o th s i d e s , by.
d 23 a n d s u b t r a c t e d fro m e q u a t i o n ( 3 ) , t h e f o l l o w i n g
w ill r e s u lt
0 .1 0 2 8 6 ( i ) ) d23
= H ri-B nm. h 2?
(7 )
S in c e t h e a b s o r p t i o n b a n d o f . a m o le c u le i s b r o a d , t h e
s t r e n g t h o f a m o le c u l a r e l e c t r o n i c t r a n s i t i o n c a n b e
d e f i n e d b y t h e i n t e g r a l o f th e . i n t e n s i t y , o v e r t h e w hole
b a n d o f th e . p a r t i c u l a r e l e c t r o n i c , t r a n s i t i o n .
Then
e q u a t i o n (7 ) c a n b e w r i t t e n a s
0.10286
( jD )
GlzV =
f o r m o le c u la r a b s o r p t i o n s .
Nn H nm. h ^
(8)
-7 "
I f an e l e c t r o n w ere c o n s i d e r e d t o b e a t h r e e - d im e n ­
s i o n a l h a rm o n ic o s c i l l a t o r th e n , t h e i n t e n s i t y o f
a b s o r p t i o n w ould b e
I
(9)
w h ere f nm.,, t h e o s c i l l a t o r s t r e n g t h , . . i s e q u a l t o o n e .
I n t h i s e q u a tio n n u l s
t h e m ass o f t h e e l e c t r o n and e
i s th e c h a rg e o f an e le c t r o n .
Then e q u a t i o n (9 ). c a n b e e q u a te d to . e q u a t i o n ( I ) .
to g iv e
(IQ )
When e q u a t i o n (1 0 ) i s s u b s t i t u t e d i n t o e q u a t i o n
(8 ) , th e o s c i l l a t o r s tr e n g th I s g iv e n as
til)
Thus t h e o s c i l l a t o r s t r e n g t h i s p r o p o r t i o n a l t o t h e
i n te g r a t e d a b s o rp tio n , i n t e n s i t y .
The mean, l i f e t i m e f o r s p o n ta n e o u s e m is s io n fro m
an e x c i t e d s t a t e o f a m o le c u le i s t h e i n v e r s e o f A,
th e E in s te in t r a n s i t i o n p r o b a b ility c o e f f ic ie n t f o r
s p o n ta n e o u s e m i s s io n .
The s p o n ta n e o u s e m is s io n p r o b a ­
b i l i t y was: shown b y , E i n s t e i n t o b e d i r e c t l y p r o p o r t i o n a l
to th e c o rre s p o n d in g a b s o r p tio n p r o b a b i l it y and to th e
t h i r d pow er o f t h e f r e q u e n c y o f t h e t r a n s i t i o n .
I f t h e m o le c u le h a s two. e l e c t r o n i c s t a t e s ,
a g ro u n d
s t a t e I a n d an e x c i t e d s t a t e u,,„ t h e c o r r e s p o n d in g e l e c ­
t r o n i c wave f u n c t i o n s may b e c a l l e d © - ,,a n d
0 ..
A
u
s e r i e s o f v i b r a t i o n a l s t a t e s a r e a s s o c i a t e d w ith e a c h
e le c tro n ic le v e l.
I n t h e B o rn -O p p e n h e im e r a p p r o x im a tio n ,
e a c h v i b r o n i c s t a t e h a s a wave f u n c t i o n
w h ic h c a n
b e w r i t t e n a s .a p r o d u c t o f a n e l e c t r o n i c f u n c t i o n
and
= 0 U
O
w here a a n d b a r e t h e q u an tu m
n u m b ers d e s c r i b i n g , t h e s t a t e o f n u c l e a r m o tio n .
I f a l a r g e num ber o f t h e s e m o le c u l e s , im m ersed
i n a n o n a b s o r b in g medium o f r e f r a c t i v e in d e x n , a r e
i n t h e r m a l e q u i l i b r i u m w i t h i n a c a v i t y I n some m a t e r i a l
a t a t e m p e r a t u r e T,, t h e r a d i a t i o n d e n s i t y w i t h in , t h e
medium i s g i v e n b y P l a n c k 's b la c k b o d y r a d i a t i o n la w
=■ ( 8 ' Tf h
3 n 3/ o 5 )
[e x p . ( h ^ / k T ) - l ] - 1
(
12 ) .
w h ere l J i s t h e fre q u e n c y , i n c y .c X e s/se c .
T h ese m o le c u le s c a n b e e x c i t e d fro m s t a t e l a t o
s t a t e u b b y t r a n s i t i o n s i n d u c e d .b y t h e . r a d i a t i o n i n
t h e c a v i t y . _ The r a t e o f m o le c u le s u n d e rg o in g ; t h i s
t r a n s i t i o n by a b s o rp tio n o f r a d i a t i o n i s
Bla -> u t , - > ( ^ l a ^ ut,>
.
(1 3 ).
w h e re Wl a ,. i s t h e n u m b e r. o f m o le c u le s , i n s t a t e l a .
M o le c u le s , i n s t a t e ub c a n go t o . s t a t e l a .by s p o n ta n e o u s
e m is s io n w ith p r o b a b i l i t y
w ith p r o b a b i l i t y
l a , o r b y in d u c e d e m is s io n
^ a, /~* ^ u b I a ^ *
TIie r a t e , a t
w h ich m o le c u le s u n d e rg o t h i s t r a n s i t i o n downw ard i s
KU"C f Au b - - l . i + Bub . l a
(‘
= Bl a ^ u b r Bna ^ ub^ l a =
" h e r e Bu b ^ l a
ut)-
.«
e q u i l i b r i u m t h e tw o , o p p o s in g r a t e s m u st b e e q u a l , so
i f e x p r e s s i o n s ( 1 3 ) a n d (1 4 ) a r e e q u a te d , t h e r e s u l t a n t
e q u a tio n i s
^ub - ^ la /® u b - > l a -""
j j ^ la ^ u b ^
( ^ u b ^ l a ^ * .........
/A c co rd in g , to. t h e B o ltz m an n d i s t r i b u t i o n la w , t h e num ber
-.-I
.
'
1
of. .m o le c u le s i n e a c h o f t h e two s t a t e s a t e q u il i b r i u m ,
i s r e la te d by
-1 0 -
11U b A la
(1 6 )
= exP L ^ h y U b -^ la A t M ■
I f e q u a t i o n s (12.) a n d (16) a r e s u b s t i t u t e d I n t o e q u a t io n
( 1 5 ) , t h e .r e s u l t a n t i s E i n s t e i n 's r e l a t i o n
(IT )
u b .-> la
I n t h e u s u a l a b s o r p t i o n e x p e r im e n t t h e m o la r e x t i n o
tio n c o e ffic ie n t
£
c a n a l s o b e d e f i n e d by
Z 9 ( 7 ^ , 1 ) / / ^ (/^,0) =■ 10~ & ( ^ ) 01 - e - 2 - 3 9 3 e (7^ )C1
(18)
i f y 0 ( T J 9I ) i s t h e r a d i a t i o n d e n s i t y i n t h e l i g h t beam
a f t e r i t h a s p a s s e d a d i s t a n c e I th r o u g h t h e sa m p le
an d / ° ( TP9Q) i s t h e i n i t i a l r a d i a t i o n d e n s i t y .
a s h o rt d is ta n c e d I
If
i s c o n s id e re d , th e change i n r a d i a ­
t i o n d e n s i t y may b e w r i t t e n a s
-
a
( Y) ) = . 2 .3 0 3 «
( '.') / • ' ( . ; »o) o a i
(19)
A l l t h e m o le c u le s w i l l b e assum ed t o b e i n t h e
g ro u n d v i b r o n i c s t a t e ,
f o r ease o f d e riv a tio n .
s i n c e t h e r e s u l t w i l l n o t b e m a t e r i a l l y d i f f e r e n t th a n
if the true distribution of molecules in the'fVibi^onic
j
j
'
I
.
s t a t e s w ere u s e d .
When N, i s , t h e num ber o f m o le c u le s
-IB . '
i n t h e l o w e s t v i b r a t i o n a l l e v e l p e r c m .^ c r o s s - s e c t i o n
an d Z
i s A vogadro *s n u m b er, t h e f o l l o w i n g e q u a l i t y
==
11
”
c a n "be m ade:
O d l =
F u r th e r m o r e
1000 .Nl o Tf - 1 .
(
20)
(
21 )
A N(% ;), t h e num ber o f m o le c u le s e x c i t b d
p e r s e c o n d w ith e n e rg y h V
a N( V
) =
i s g i v e n by
-c d y5 ( ^ ) / ( h
V
n ).
The c o m b in a tio n o f e q u a t i o n s (.19) , (2 0 ) a n d (2 1 ) g i v e s
E q u a tio n (.2 2 ). g i v e s t h e p r o b a b i l i t y , t h a t a m o le c u le
i n s t a t e I o w i l l a b s o r b a q uantum o f e n e r g y . h "Z) and
go t o some e x c i t e d s t a t e .
To o b t a i n t h e p r o b a b i l i t y
o f g o in g ..to s t a t e u b , e q u a t i o n ( 2 2 ) m u st b e i n t e g r a t e d
o v er th e f i n i t e ran g e o f fre q u e n c ie s f o r t h i s o c c u rre n c e .
Then
( V , 0 ) c a n b e assum ed c o n s t a n t o v e r . t h i s ra n g e
an d e q u a l t o
e q u a tio n i s
[
^ lo -> u b ^ '
Thu s t h e i n t e g r a t e d
.
-1 2 -
2303 c
h z^f n I o ub- -
^ l o ^ u b ) a l a -z)
lO r? U b
Z5 ( y IO ^ U b )
. (2 3 )
T h is e q u a t i o n show s fozr a m o le c u le I n s t a t e I o
t h a t th e p r o b a b i l i t y o f u n d e rg o in g ;a t r a n s i t i o n to
s t a t e u b - ls p r o p o r tio n a l. to /
°
(
*- t h e C o n s ta n t
o f p r o p o r t i o n a l i t y b e in g t h e te rm i n b r a c k e t s .
E x p re s ­
s i o n ( 1 3 ). g a v e a s i m i l a r r e l a t i o n f o r a m o le c u le i n
s t a t e I o w ith t h e . p r o p o r t i o n a l i t y , c o n s t a n t b e i n g g iv e n
a s Bl o - 5>ub*
T h e re fo re , id e n tif y in g , th e c o n s ta n t
Bl o - 5>ub
b ra c k e te d e x p re s s io n o f e q u a tio n ( 23) ■
g iv e s
J
Bl o ^ ub ^ h
1 6 (Z7 l 0 ^ u b ) d l n ^ I o - ^ u b '
(2 4 )
S t i l l a ssu m in g t h a t a l l t h e m o le c u le s o r i g i n a t e
I' / '
i n t h e s t a t e . I o i . i t i s p o s s i b l e t o sum e x p r e s s i o n (24;)
V
■ '!
"
.
:
o v e r a l l th e v i b r a t io n a l l e v e ls o f th e e x c ite d e le c ­
tr o n ic s t a t e to o b ta in a p r o b a b ility c o e f f i c i e n t f o r
a l l t r a n s i t i o n s t o t h e e l e c t r o n i c : s t a t e u ^ . T h is i s
g i v e n by
Bl o - » u
=
^
5Io ^ u b
:
-1 3 -
2303 G
nIo -^ u
Io
a? d l n ;
(2 5 )
lti'-^ u
w h ere ^ o -^ u d s ^ h e . mean r e f r a c t i v e In d e x o f. t h e
n o n - a b s o r b in g medium o v e r t h e a b s o r p t i o n b an d , w h ic h
i s an a p p r o x i m a t i o n .
When a m o le c u le g o e s from , a lo w e r e l e c t r o n i c s t a t e
t o an u p p e r one by. a b s o r p t i o n i t w i l l o f t e n b e to
an e x c ite d v i b r a t i o n a l l e v e l o f th e u p p e r e le c t r o n i c
s ta te .
H ow ever, i f t h e m o le c u le i s i n a c o n d e n s e d
medium,., i t w i l l U s u a l l y l o s e - e n e r g y b y c o l l i s i o n u n t i l
i t i s i n th e lo w e s t v i b r a t i o n a l l e v e l o f th e s t a t e .
In
f l u o r e s c i n g , t h e m o le c u le may t h e n go t o v a r i o u s v i b r a ­
t i o n a l l e v e l s o f t h e g ro u n d e l e c t r o n i c s t a t e .
Thus
ri n a b s o r p t i o n t h e t r a n s i t i o n s o b s e r v e d a r e t h e I o -e>/_ub,
b
w h ile i n f l u o r e s c e n c e th e y a r e t h e uo
2~ ^ a » It- i s
'
a
n e c e s s a r y , t h e r e f o r e , ,to f i n d a r e l a t i o n s h i p b e tw e e n
b I o -^ u
^ 5 I o ->ub ^n d Auo ^ l
I _ Auo ^ l a *
The wave f u n c t i o n s .of v i b r b n i c s t a t e s , . / '*
a re
f u n c t i o n s o f b o t h t h e e l e c t r o n i c c o o r d i n a t e s x .and
t h e n u c l e a r c o o r d i n a t e s , w h ich may. b e ta k e n a s t h e
n o rm a l c o o r d i n a t e s Q,.... I f M(x.) i s t h e E l e c t r i c d i p o l e
o p e r a t o r f o r . .t h e e l e c t r o n s t h e n t h e p r o b a b i l i t y f o r
in d u c e d a b s o r p t i o n o r e m issio n ,., b e t w e e n . two s t a t e s i s
p r o p o r t i o n a l t o t h e s q u a r e o f t h e m a t r ix e le m e n t o f
M.(x) b e tw e e n t h e two s t a t e s ;
th a t is
'
_
'I a -> u h -
® u b -T -Ia
=K
M(%)
uh
dx
d Q
(2^ )
w h ere K i s t h e p r o p o r t i o n a l i t y , c o n s t a n t .
The wave f u n c t i o n s c a n h e w r i t t e n a s p r o d u c t s o f
t h e e l e c t r o n i c and v i b r a t i o n a l p a r t s .,, f o r e x a m p le ,
^ l a (jC’ Q) =
^
(2 7 )
S o . t h e i n t e g r a l i n e q u a t i o n (2 6 ) may b e e x p r e s s e d a s
.^(x).
MXU(Ct) ^
(28)
w h ere
Ml u (Q) . - JrG 1^ ( X f Q) M(x) 0
u (x,Q) d x
i s a n e l e c t r o n i c t r a n s i t i o n moment i n t e g r a l f o r t h e
t r a n s i t i o n , , a ssu m in g t h e n u c l e i t o b e f i x e d i n a p o s i t i o n
g.
I t c a n b e e x p a n d e d i n . a., p o w er ( ,s e r i e s i n t h e n o rm a l
c o o r d i n a t e s o f t h e m o le c u le :
V
cu
=
Mi u ( o > +
r
.(j W
j
(2 9 )
^
F o r s t r o n g l y a llo w e d t r a n s i t i o n s i n a m o le c u le ,
a n d f o r r e a s o n a b l y s m a ll d is p l a c e m e n ts fro m t h e e q u i l i b ­
riu m . n u c l e a r c o n f i g u r a t i o n , t h e z e r p t h - o r d e r te rm i n
t h i s e x p a n s io n s h o u ld p e t h e d o m in a n t o n e .
W ith t h e
a s s u m p tio n t h a t t h i s i s t h e c a s e , e q u a t i o n ( 2 6 ) r e d u c e s
to
B,
Ia -^ u b
B
ub -> la
(3 0 )
K j H l u (O)
The q u a n t i t y n e c e s s a r y . f o r t h e c a l c u l a t i o n o f t h e
life tim e is
t h e r a t e c o n s t a n t f o r e m is s io n
fro m t h e lo w e s t v i b r a t i o n a l , l e v e l o f t h e e x c i t e d
e le c tro n ic s t a te .to
a l l t h e v i b r a t i o n a l l e v e l s of. t h e
g ro u n d e l e c t r o n i c s t a t e .
From e q u a t i o n s (1 7 ) an d (30)
t h i s can be w r itte n as
aU0
-* !. ^
Z a uo -T=-Ia
a .
•-'R Tr h :1uo , . l 3 /c 3 ) E i :4l u ( 0 >i 2
6>
uo -T=-Ia
A
dQ
(31)
16
w h ere n Uov-^I
t h e mean r e f r a c t i v e in d e x o f t h e
n o n - a b s o r b in g medium o v e r t h e f l u o r e s c e n c e b a n d , an
a p p r o x im a tio n .
I t i s d e s i r a b l e t o b e a b le , t o e v a l u a t e , t h e ie rin
I
3
e x p e r i m e n t a l l y .... ,S in c e
H ^f * $
a
uoi
.t h e f l u o r e s c e n c e b a n d i s n o t n a rr o w , ai p o s s i b l e p r o c e d u r e
c a n b e d e r i v e d by, d i v i d i n g t h e te r m by, Y_ J $
W 3.Q,
a
la
uo
= 1.
T h is sum i s e q u a l t o u n i t y s i n c e t h e (p
c o m p rise .
la
a c o m p le te p r th o n o r m a l s e t i n ^ s p a c e ,
T h is: g iv e s , t h e
fo llo w in g e x p re s s io n :
^a-
dQ
^ ; uo , - I a 3
i
IW xi-
i o
aa
E ach te rm I n t h e n u m e r a to r o f t h i s e x p r e s s i o n i s p r o p o r ­
t i o n a l t o t h e i n t e n s i t y o f on e v i b r o n l c b a n d .i n t h e
f l u o r e s c e n c e sp e ctru m ..
E ach te r m i n t h e d e n o m in a to r
i s p r o p o r t i o n a l t o 7? “ ^ tim e s t h e in te n s ity ... o f one
v ib ro n lc b an d .
The sums o v e r a l l t h e v i b r o n l c b a n d s
c a n b e r e p l a c e d by i n t e g r a l s o v e r t h e f l u o r e s c e n c e
s p e c tr u m , so t h a t t h e e x p r e s s i o n r e d u c e s t o
f i ( - i > ) a-!)..
T) - 3 \ : - l
X. f ■/ a v '
(33):
-1 7 -
t h e r e c i p r o c a l o f t h e mean v a lu e o f I?
i n th e
f l u o r e s c e n c e s p e c tr u m , w h ere I ( t ) ) , th e . I n t e n s i t y i n
t h e sp e c tru m ^ , i s . m e a s u re d i n te r m s o f r e l a t i v e num bers:
o f q u a n ta a t e a c h f r e q u e n c y .
. . Frbm e q u a t i o n (3 0 ) when Bl
o
i s summed o v e r b ,
th e r e s u l t i s
b I o.-, u
Bio
t I v
ub.
o ? ! '8
^
I /
Tt U1, a s r
*
(34).
s in c e th e
in & sp ace.
c o m p ris e a c o m p le te o r th o n o r m a l s e t
T hus fro m e q u a t i o n s (3 4 ) a n d . ( 2 5 ) , t h e
e x p re s s io n s f o r
K
Oan b e e q u a t e d : .
Ml i i (O) I 2
2503 c
J
6 ( V 16.-^U ) d ; l n ^ I o ^ u
(35).
I f e q u a t i o n s (3 3 ) a n d (3 5 ) a r e s u b s t i t u t e d i n t o e q u a t i o n
(3 1 ), th e r e s u l t i s
8 X 2303 T f Uxxq^ 1?
aU O -?!
-I
“
c2
nI o ^- ?Vul .
I f e i t h e r o r b o th o f t h e e l e c t r o n i c s t a t e s .,are
d e g e n e r a t e , a f a c t o r o f S jZ s u i s m u l t i p l i e d t im e s t h e
r i g h t - hiand s i d e o f e q u a t i o n (3 .6 ) t o sum o v e r t h e s e
s ta te s .
I t - i 'S m ore c o n v e n ie n t,, t o u § e t h i s e q u a t i o n i n te rm s
o f 19 , i n s t e a d o f 19 .
,The r e s u l t o f t h i s c o n v e r s i o n i s
3
(3 7 )
T h is e q u a t i o n i s a p p l i c a b l e t o s t r o n g l y a llo w e d
t r a n s i t i o n s an d t o o n ly r e a s o n a b l y s m a ll d is p l a c e m e n ts
o f t h e ato m s from t h e e q u i l i b r i u m n u c l e a r c o n f i g u r a t i o n
i n b o th e le c t r o n i c s t a t e s . 9
-1 9 -
AniO th e r q u a n t i t y o f i n t e r e s t w h ic h may b e d e te r m in e d
fro m t h e e m is s io n .sp e c tru m i s t h e quantum e f f i c i e n c y o f
th e f lu o re s c e n c e .
To d e te r m in e f l u o r e s c e n c e e f f i c i e n c y
d i r e c t l y i t i s n e c e s s a r y t o com pare t h e r a t e o f a b s o r p ­
t i o n o f e x c i t i n g l i g h t w ith t h e t o t a l r a t e o f e m is s io n
o f f l u o r e s c e n c e o f a l l w a v e le n g th s and i n a l l d i r e c t i o n s .
In p rin c ip le th is i s
s im p le b u t i n p r a c t i c e i t i s a
*
d i f f i c u l t e x p e r im e n t t o p e rfo rm w ith p r e c i s i o n .
An
e a s i e r m ethod b y w h ich f l u o r e s c e n c e e f f i c i e n c y may b e
d e te r m in e d is . c o m p a ris o n b e tw e e n a known " s t a n d a r d "
in
s u b s ta n c e and t h e m a t e r i a l o f i n t e r e s t .
!
I f a s o l u t i o n o f t h e com pound o f i n t e r e s t , i s d i l u t e
en o u g h t h a t e r r o r s due to e x c e s s i v e a b s o r p t i o n o f e x c i t i n g
l i g h t o r to s e l f - a b s o r p t i o n o f th e f lu o r e s c e n c e a re
n e g l i g i b l e , t h e t o t a l r a t e o f e m is s io n o f f l u o r e s c e n c e
i s p r o p o r t i o n a l t o t h e p r o d u c t I q- £
i s t h e q uantum e f f i c i e n c y .
C I
Now t h e i n t e g r a t e d a r e a u n d e r
t h e c o r r e c t e d f l u o r e s c e n c e s p e c tru m i s a l s o p r o p o r t i o n a l
to t h e t o t a l r a t e o f. e m is s io n o f f l u o r e s c e n c e .
T hus,
i f t h e f l u o r e s c e n c e e m is s io n s p e c t r a o f two s o l u t i o n s
a r e m e a su re d w ith t h e . same i n s t r u m e n t a l g e o m e try and
a t t h e same i n t e n s i t y o f e x c i t i n g l i g h t , th e . r a t i o
of
t h e two o b s e r v e d f l u o r e s c e n c e i n t e n s i t i e s i s g i v e n by
»20«
^2 _
Q1
aI>ea2
B re a 1
..1Q e 2 c Qi l ^2
1 O £ I 0I 1 f l
.
(38)
I f t h e a b s o l u t e f l u o r e s c e n c e e f f i c i e n c y ,. (.. ^ 1 ) o f one o f
t h e s u b s t a n c e s i s known,., t h a t o f t h e o t h e r i s s im p ly
11
c a l c u l & te d .
i
In . p r a c t i c e m o st o f t h e ab o v e c o n d i t i o n s a r e n o t
m et so c o r r e c t i o n s m u st b e made, f o r them .
A c h a n g e i n r e f r a c t i v e in d e x (h ) o f t h e s o l u t i o n
r e s u l t s i n a v a r i a t i o n .i n t h e a n g l e s o f t h e r a y s e m e rg in g
•
J
fro m a p l a n e - c u v e t t e - a i r i n t e r f a c e .
Thus i f . th e , two
=I
s u b s ta n c e s to . b e com pared a r e d i s s o l v e d , i n d i f f e r e n t
s o l v e n t s , t h e o b s e r v e d i n t e n s i t i e s must, b e c o r r e c t e d by
m u l t i p l y i n g , b y n£ . 12
I f t h e two s u b s ta n c e s a r e e x c i t e d a t two d i f f e r e n t
w a v e le n g th s , t h e n t h e i n t e n s i t y . o f t h e e x c i t i n g l i g h t
i s p r o b a b ly , d i f f e r e n t . .
To c o r r e c t f o 6 t h i s , e a c h a r e a
c a n b e d i v i d e d by i t s p e a k h e ig h t '.
Then t h e r a t i o
t h e s e two n um bers c a n b e m u l t i p l i e d by.; a r a t i o
of
o f th e
f l u o r e s c e n c e p e a k h e i g h t s when b o t h s u b s ta n c e s a r e e x ­
c i t e d by. l i g h t o f t h e same w a v e le n g th ,., u s u a l l y som ew h ere b e tw e e n t h e two o r i g i n a l e x c i t i n g w a v e le n g th s ..
The e q u a t i o n i s
.
BB2 l«
/ a re a 2
( p k ., h t . g / y? g d (p k . h t . g )
^ 1Q. ^ 2 C2 ^
.
'/ . a r e E1
■ (p k . h t . i ) /i ^ ‘ '
6 ^ cI 1 / l
VPk. I i t z 1 ! / I 1
/
.
( 3 9 )'
The f l u o r e s c e n c e s p e c t r a o f t h e two s u b s t a n c e s , i n
g e n e r a l , . . w i l l n o t b e o v e r t h e same w a v e le n g th r e g i o n .
Sd t h e a r e a s m u st b e c o r r e c t e d f o r t h e s e t h r e e w a v e le n g th
d e p e n d e n t f a c t o r s : ' t h e quantum e f f i c i e n c y , o f t h e p h o to ­
m u l t i p l i e r , t h e b a n d w id th o f thenim o n o ch ro m ato r and t h e
t r a n s m i s s i o n f a c t o r o f t h e m o n o c h ro m a to r. . I f
is
th e p h o to m u ltip lie r re s p o n s e , th e n
Rs l
= (d Q,/d R ) SL ( S a )
(40)
w h ere (d Q,/d y? )
i s t h e t r u e i n t e n s i t y a t w a v e le n g th A
SL
and S A i s t h e c o r r e c t i o n f o r t h e t h r e e w a v e le n g th
dependent f a c to r s .
I f a s e r i e s o f .compounds a r e a v a i l a b l e f o r w hich
th e . c o r r e c t e d f l u o r e s c e n c e e m is s io n s p e c tru m h a s b e e n
p r e c i s e l y d e te r m in e d , m ea su re m e n t o f t h e u n c o r r e c t e d
s p e c tru m o f t h e s e com pounds w ith t h e i n s t r u m e n t t o b e
c a l i b r a t e d p e rm its th e d i r e c t c a l c u l a t i o n o f S ^
s in c e
(d Q,/d Ji )g.£ now r e p r e s e n t s t h e known s p e c t r a l d i s t r i b u t i o n
o f o n e o f t h e s t a n d a r d com pounds an d
re a d in g s .\
th e o b se rv ed
The compound m ust b e f r e e fro m o t h e r f l u o r e s c e n t
"22=
m a t e r i a l a n d t h e f l u o r e s c e n c e m u st b e m e a su re d u n d e r
t h e same c o n d i t i o n s ' o f t e m p e r a t u r e , s o l v e n t,, c o n c e n t r a t i o n , pH,,, e t c . f o r w h ich th e . s t a n d a r d f l u o r e s c e n c e
c u rv e i s p ro v id e d ,.
Then t h i s c a l c u l a t e d Sy^ c a n b e
u s e d t o c o r r e c t t h e i n t e n s i t i e s o f t h e two s u b s ta n c e s
I 2l
u s e d f o r t h e quan tu m e f f i c i e n c y d e t e r m i n a t i o n .
RESULTS AND DISCUSSION
The c y a n in e d y e s I t h r o u g h VI w ere s e l e c t e d f o r
a s tu d y o f t h e i r a b s o r p t i o n and f l u o r e s c e n c e s p e c t r a ,
t h e i n t r i n s i c l i f e t i m e o f . t h e i r f i r s t e x c i t e d s & h g le t
s ta te ,
t h e f l u o r e s c e n c e e f f i c i e n c y , from t h a t s t a t e , and
a c a l c u l a t i o n of. t h e o b s e r v a b l e l i f e t i m e o f t h e f i r s t
e x c ite d s in g le t s t a t e .
T h ese p a r t i c u l a r d y e s w ere
c h o s e n b e c a u s e th e y w ere t h e m o st r e a d i l y a v a i l a b l e
v i n y lo g o u s s e r i e s o f d y e s which, had' t h e u n u s u a l p r o p e r t y
1
•
t h a t t h e b o n d o r d e r i s t h e same b e tw e e n any two c a rb o n s
i n t h e m e th y le n e c h a i n (S e e p , 2 f o r . a m ore c o m p le te
d is c u s s io n o f t h i s p r o p e r ty .) .
T h ese d y e s a r e a l s o
■o f i n t e r e s t b e c a u s e t h e y c a n t r a n s f e r e n e rg y fro m th e
f i r s t e x c ite d s in g le t s t a t e .
One ex am p le o f t h i s a b i l i t y
■.
i
!
i
i s t h e i r u s e i n s e n s i t i z i n g p h p to g r a p h ic f i l m s .
The
r a t e o f t h e e n e rg y t r a n s f e r m u st b e a t t h e l e a s t a s
g r e a t a s th e . r a t e o f e m is s io n fro m tfye f i r s t e x c i t e d
s t a t e i n o r d e r t o b e c o m p e t i t i v e w ith t h e f l u o r e s c e n c e .
I f t h e r a t e o f t h i s e m is s io n c o u ld b e d e te r m in e d e i t h e r
b y m e a su re m e n t o r c a l c u l a t i o n , t h e n t h i s w ould b e a
lo w e r l i m i t on t h e r a t e o f e n e rg y t r a n s f e r .
E ven th o u g h
t h e r e h a v e b e e n some r e p o r t s o f t h e a b s o r p t i o n maxima"
a n d some rough, e s t i m a t e s o f t h e f l u o r e s c e n c e m axim a (S ee
-2 3 -
-2 4 -
p . 3 f o r d e t a i l s an d r e f e r e n c e s .
t h e s e d a t a c o u ld n o t
be u sed f o r f u r t h e r c a lc u la tio n s b e ca u se th e s o lv e n t
m u st b e t h e same f o r b o th t h e a b s o r p t i o n and t h e f l u o r e s ­
c e n c e an d t h e i n t e g r a t e d a r e a s u n d e r t h e s p e c t r a m ust
b e know n.
A lso no. o b s e r v a b l e f l u o r e s c e n c e h a s e v e r
b e e n r e p o r t e d f o r Dye I .
Thus t h e p u r p o s e o f t h i s r e s e a r c h
was t o d e te r m in e e i t h e r by m e a su re m e n t o r c a l c u l a t i o n , t h e
o s c i l l a t o r s tr e n g th s o f th e a b so rb a n c e s; th e c o rr e c te d
in te g r a t e d a re a s o f th e f lu o r e s c e n c e s ; th e i n t r i n s i c
life tim e s ,
t h e q uantum e f f i c i e n c i e s , and t h e o b s e r v a b l e
l i f e t i m e s '(t h e i n v e r s e o f t h e . sum o f t h e r a t e s . f*or _a l l
d e c a y p r o c e s s e s .) f o r t h e f i r s t e x c ite d , s i n g l e t s t a t e s o f
tjtiese d y e s , ■
. E ac h o f t h e d y e s was p r e p a r e d by t h e m ethod o u t l i n e d
i n . d e t a i l i n t h e e x p e r i m e n t a l s e c t i o n ..
A fte r th e i n i t i a l
r e a c t i o n b e tw e e n 3- e t h y l - 2-m e th y lb e n z o x a z o liu m i o d i d e
w ith i s o p e h t y l n i t r i t e ,
s a lt.
t h e dye, fo rm e d i s t h e t r i i o d i d e
Tb p r e p a r e t h e i o d i d e i n o r d e r t o h a v e t h e same
a n io n a s t h e o t h e r d y e s , t h e t r i i o d i d e was r e d u c e d by
~~i
b u b b l in g s u l f u r d i o x i d e th r o u g h a s u s p e n s io n o f t h e d y e .
Then t h e r e d u c e d dy e was r e c r y s t a l l i z e d from m e th a n o l.
Upon t h e s e c o n d r e c r y s t a l l i z a t i o n ,
t h e dye a p p a r e n t l y
deco m p osed i n t o a foam y y e llo w s u b s ta n c e .
S in c e t h e
i o d i d e was n o t p u r e a f t e r o n ly , on e r e c r y s t a l l i z a t i o n
-2 5 -
and t h e t r i I o d i d e was fo u n d t o b e p u re by e le m e n t a l
a n a l y s i s , t h e t r i i o d i d e o f Dye IV was u s e d f o r t h e
s p e c tro s c o p ic s tu d ie s .
A p o s s i b l e m echanism f o r t h e f o r m a tio n o f Dyej IV ,
s i m i l a r t o t h a t p ro p o s e d by F i s h e r and H am er-^ f o r th e
t h l a c y a n l n e Dye I , c a n b e w r i t t e n a s f o l lo w s :
q)/
-Me
+
G5H11ONO
—>
C5H11OH
-f
4Et
Xe
Et
4- HCN -f
X°
- 26-
I t i s q u e s t i o n a b l e w h e th e r t h e f i n a l c o u p lin g s t e p o f
t h i s m ech an ism , t h a t . o f \2- c y a n o - 3 - e t h y Ib e n z o x a z o liu m
i o d i d e w ith 3- e t h y l - 2-m e th y Ib e n z o x a z o liu m i o d i d e , w ould
o c cu r.
The t r i i o d i d e u n io n i s fo rm e d by t h e o x i d a t i o n o f
two i o d i d e i o n s t o i o d i n e w h ic h t h e n r e a c t s w i t h an
i o d i d e i o n t o fo rm t h e com plex i o n , . t r i i o d i d e .
The
o x id iz in g .a g e n t in th e r e a c tio n i s th e is o p e n ty l n i t r i t e
w h ic h i s p r o b a b ly r e d u c e d t o n i t r i c , o x id e a n d i s o p e n t y l
a lc o h o l.O r i g i n a l l y , a t h i r d v in y lo g p u s s e r i e s o f d y e s w@.B,9
to have b een s tu d ie d a ls o .
The d y e 1 , 1 ' , 3 , 3 ' - t e t r a -
e th y I b e n z im id a z o lo c a r b o c y a n in e i o d i d e c o u ld b e fo rm ed
i n o n ly ,, a . s m a ll y i e l d a n d v e ry p o o r p u r i t y . e v e n u n d e r
d r a s t i c r e a c t i o n c o n d i t i o n s .su c h a s t h e r e a c t i o n o f
1 , 3- d i e t h y l - 2- m e th y lb e n z im id a z o Iiu m i o d i d e i n n i t r o ­
b e n z e n e w ith 3 M so d iu m ’a t h o x i d e a s a b a s i c c a t a l y s t .
The p r o d u c t o f t h i s r e a c t i o n a f t e r f i v e r e c r y s t a l l l z a t i o h s fro m m e th a n o l h a d an e x t i n c t i o n c o e f f i c i e n t o f 51
a t t h e 486 mja~ maximum.
The e x t i n c t i o n c o e f f i c i e n t a t
t h e maximum a b s o r p t i o n f o r a llo w e d t r a n s i t i o n s su c h
as th o s e i n th e s e dyes a re u s u a lly , i n th e r e g io n o f
10^.
T h e r e f o r e ; t h e stu d y , o f t h i s , s e r i e s o f d y e s was
abandoned.
I n F i g u r e 2 m ay. b e fo u n d th e. a b s o r p t i o n s p e c t r a
o f t h e l o w e s t e l e c t r o n i c t r a n s i t i o n f o r D y e s.T ,. I I and
I I I , w h ile F i g u r e 3 ..g i v e s t h e a b s o r p t i o n s p e c t r a i*or
Dyes IV,. V and VI.-. T h ese s p e c t r a w ere ex am in e d i n d i l u t e
s o l u t i o n s o f about" 10 " ^ M. i n m e th a n o l and a r e p l o t t e d
b y £ , t h e e x t i n c t i o n c o e f f i c i e n t , v e r s u s t h e w a v e le n g th
i n m/yC.
A l l t h e s p e c t r a h a v e a s i m i l a r s h a p e w ith
(
a s h o u l d e r a t s h o r t e r w a v e le n g th .
I n each s e r i e s th e
e x t i n c t i o n c o e f f i c i e n t a t t h e maximum a b s o r p t i o n i n ­
c r e a s e s . a s th e c h a in le n g th i n c r e a s e s .
As c a l c u l a t e d
by e q u a tio n (1 1 ) , th e o s c i l l a t o r s tr e n g th s i m il a r ly
in c re a s e s .
The i n t e g r a t i o n f o r t h e o s c i l l a t o r s t r e n g t h
was p e rfo rm e d b y t h e m ethod o f t h e sum o f t h e a r e a s o f
s m a ll r e c t a n g l e s .
The e r r o r i n t h e r e p o r t e d o s c i l l a t o r
s tr e n g th s i s e s tim a te d to b e a b o u t th r e e p e r c e n t.
The
a b s o r p t i o n r e s u l t s a r e su m m arized I n T a b le I .
F i g u r e 4 gHeres t h e e m is s io n s p e c t r a a t room te m p e r­
a t u r e f o r d i l u t e m e th a n o l s o l u t i o n s o f Dyes I , I I and
III,
w h ile F i g u r e .5 g i v e s t h e e m is s io n s p e c t r a f o r
Dyes IV , V an d VI.. . The c o n c e n t r a t i o n s o f t h e d y e s w ere
a b o u t 10” ^ M f o r Dyes, I I I .and VI a n d a b o u t 10" ^
a l l th e o th e r s .
m
fo r
T h e se s p e c t r a a r e c o r r e c t e d f o r t h e
q u an tu m e f f i c i e n c y , o f t h e p h o t o m u l t i p l i e r a s g i v e n by
t h e c u rv e i n F i g u r e 6 f o r a t y p i c a l tu b e o f t h i s ty p e
Figure
i
Wavelength in m y/u
25
Figure 3
20 -
, I
4 1: 1
!ill
I! '
I
, I I- 1« I•l - ' I
M
i
J
* • - Ii i ; I
I• ; .
I •
-ill
4
X 10
-I -I .
I ; ■
}I I
' I : ; 1I
rlif: C
i ; I
!i I
'4
!I
('
3
I h'
i i I
11i t
Hi
5 -
- : I i : ! : . ; ;
'
I
i
V
600
Wavelength in mX*-
■ i- 4 f
r ' r
i t : .
. ;I i
; r| I
t i ; •
■H
H ^,
’ T- + :
m
'
i -i
X - 444- 4 t
I ' !I J L i t
700
# : -r^—t—{-I f :t [4-1 I
i t
I
!
I T 1.1 ■ i t r l 1 11
800
(arbitrary units)
4
Intensity
i
&
i
300
400
500
600
Wavelength in myW-
700
800
4
i
E
1
I
CO
I
I
700
400
Wavelength in m
800
Figure 6
t- -4-
IL I
-5 C -
i IT l
ee
C
---- -)
I
-LTJ
M
I
\ j-j
t- r •
&
f-M *
Tl 'f-t
300
400
500
600
Wavelength in myyu
700
800
-3 3 -
T a b le I
'
-
Dye
Amax
m /c
£ max
X .1 0 -5
J& .d-z;
X IO "8
0 .8 6 8
1 .9 0 .
0.822
f
I
4 2 4 .0
II
5 5 6 .0 .
1 .5 6
2 .5 2
1 .0 9
III
6 5 1 .5
2 .5 3
- 3 .5 1 -
1 .5 2
IV
3 7 5 .5 .
0 .7 8 6
2 .3 9
1.0-3
V
4 8 3 .0
1 .5 1
2 .9 0
1 ,2 5
VI
5 7 9 .0
2 .2 7
3 .4 2
1 .4 8
.
.
w here t h e quantum e f f i c i e n c y i n p e r c e n t i s p l o t t e d
a g a i n s t t h e w a v e le n g th i n m y c .
The i n t e n s i t i e s o f th e
s p e c t r a th e m s e lv e s a r e p l o t t e d i n a r b i t r a r y u n i t s . 1
The l i f e t i m e f o r s p o n ta n e o u s e m i s s io n . ^ o , i s
t h e same a s t h e o b s e r v e d l i f e t i m e o f t h e r a d i a t i v e s t a t e
i f t h e r e a r e no o t h e r c o m p e tin g p r o c e s s e s f o r t h e l o s s
o f e n e rg y .
I f t h e r e a r e o t h e r m eth o d s o f d e a c t i v a t i o n ,
th e n t h e o b s e r v e d l i f e t i m e i s
f a c t o r o f t h e quan tu m y i e l d .
s h o r t e r th a n
by t h e
. S in c e t h e l i f e t i m e i s th e
r e c ip r o c a l o f th e r a t e c o n s ta n t f o r th e t r a n s i t i o n ,
i n t h e c a s e o f no c o m p e tin g p r o c e s s e s t h e o b s e r v e d
l i f e t i m e may.. b e w r i t t e n a s
-3 4 -
Z o
w h ere k @ i s t h e ' r a t e c o n s t a n t f o r s p o n ta n e o u s e m is s io n .
When
i s t h e r a t e c o n s t a n t f o r c o m p e tin g p r o c e s s e s ,
'Ty '
t h e n t h e o b s e r v e d l i f e t i m e L may. b e g iv e n a s
or
w h ere (J) i s t h e q uantum y i e l d .
T hus t h e r a d i a t i v e l i f e ­
tim e may b e c a l c u l a t e d fro m t h e o b s e r v e d l i f e t i m e . a n d
t h e q u antum y i e l d .
H ow ever, t h e s e two q u a n t i t i e s h a d
n o t b e e n d e te r m in e d f o r t h e s e d y e s .
B u t t h e r a d i a t i v e l i f e t i m e may a l s o b e c a l c u l a t e d
fro m t h e a b s o r p t i o n an d e m is s io n s p e c t r a .
So e q u a t i o n
(3 7 ) was u s e d t o c a l c u l a t e t h e s p o n ta n e o u s e m is s io n
-3 5 -
l i f e tim e s o f t h e f i r s t e l e c t r o n i c e x c i t e d s t a t e f o r
t h e s e two s e r i e s o f . d y e s .
B o th s t a t e s o f t h e s e d y e s
w ere assu m ed t o h e n o n - d e g e n e r a t e ..
From t h e L a r id o lt - B t if h s te i n tab les-* -^, a c u rv e su c h
a s F i g u r e 7 may. b e p l o t t e d f o r t h e in d e x o f r e f r a c t i o n o f m e th a n o l v e r s u s t h e w a v e le n g th .
The v a l u e s o f nu o - > i
an d n ].0._^u . w ere o b t a i n e d from t h i s g r a p h .
The q u a n t i t y .
Z a v -1 was c a l c u l a t e d b y e q u a t io n
(33). w here e a c h o f t h e i n t e g r a l s w ere a p p ro x im a te d by
t h e m eth o d o f t h e sum o f t h e a r e a s o f s m a ll r e c t a n g l e s
fro m t h e e m is s io n s p e c tru m a n d t h e n t h e i n t e g r a l
/ l
d i v i d e d by t h e i n t e g r a l
) dV
The v a lu e o f
^ ^
I ( T l )- d D .
f ^ / ^ a v ” 1 i s p ro b a b ly , a c c u r a t e t o
ab o u t th r e e p e r c e n t.
. From t h e a b s o r p t io n , s p e c tru m t h e i n t e g r a l
/ £
_ ) d I n 2 5 . ^ was c a l c u l a t e d b y t h e m ethod
^
lo -> u
Io -^ u
o f t h e sum o f t h e a r e a s o f s m a ll r e c t a n g l e s . . S in c e
th e e r r o r i n t h i s i n t e g r a l i s e s tim a te d to b e a b o u t
t h r e e p e r c e n t,....th e t o t a l e r r o r fro m e x p e r i m e n t a l
f a c t o r s i n th e c a lc u la te d r a d i a t i v e l i f e t i m e ,
C
,
s h o u ld b e a p p ro x im a te ly , s i x p e r c e n t .
The s u l f u r c o n t a i n i n g s e r i e s o f d y e s , t h a t i s
Dyes I , I I an d I I I , . w e r e c a l c u l a t e d t o h a v e r a d i a t i v e
life tim e s ,
L 0 , a ro u n d t h r e e n a n o s e c o n d s w h ile t h e
1.334
, i.;
Figure 7
I;!
44;
1.332
MJ ■
I I" !
index of refraction for methanol
- 4-
1.330
1.328
' r' i
I
o\
VJ
rt"'
I
4-41.326
c
1.324
Wavelength in m yU»
I 44-i I
-3 7 -
o x y g e n c o n t a i n i n g . d y e s , . Dyes IV,.. V an d V I,..,w ere c a l c u ­
l a t e d t o h a v e r a d i a t i v e l i f e t i m e s a ro u n d two n a n o s e c o n d s .
So t h e r a d i a t i v e l i f e t i m e seem s t o d e p en d m ore upon
t h e h e t e r o - a t o m d i f f e r e n c e b e tw e e n t h e s e r i e s o f d y e s
t h a n u pon t h e m e th y le n e c h a in l e n g t h w i t h i n e a c h s e r i e s .
The d a t a f o r t h e l i f e t i m e c a l c u l a t i o n s a r e su m m arized
i n T a b le I I ,
As c a n b e s e e n from
d e c re a s e s th e i n t e g r a l
i n c r e a s e s f o r e a c h dye s e r i e s so t h a t t h e r a d i a t i v e
l i f e t i m e s a r e a b o u t t h e same f o r e a c h s e r i e s .
The d i f f e r
e n c e i n l i f e t i m e s o c c u r s m a in ly b e c a u s e t h e w a v e le n g th s
o f a b s o r p t i o n an d e m is s io n a r e n o t t h e same f o r t h e
two s e r i e s o f d y e s f o r t h e same m e th y le n e c h a i n l e n g t h .
The o x a c y a n in e s a r e a l l a t s h o r t e r w a v e le n g th s t h a n t h e
c o rre s p o n d in g th ia c y a n in e s .
S in c e t h e mean w avenum ber
f o r t h e f l u o r e s c e n c e b a n d i s c u b e d ,, t h i s i n c r e a s e s t h e
d i f f e r e n c e b e tw e e n t h e two s e r i e s ,
a s r e f l e c t e d by th e
l i f e t i m e f o r s p o n t a n e o u s . e m is s io n .
So t h e r o o t o f t h e
m a t t e r i s t h e s m a l l e r d i f f e r e n c e i n e n erg y , b e tw e e n th e
g ro u n d s t a t e and t h e e x c i t e d s t a t e i n t h e t h i a e y a n i n e
d y e s a s co m p ared t o t h e o x a c y a n in e d y e s .
C o n s i d e r i n g . t h e s u l f u r s o r o x y g e n s c o n ju g a te d i n t o
t h e m e th y le n e c h a i n a s w e ll a s t h e n i t r o g e n s f o r t h e
TABLE II
Dye
n
uo-H
nIo-^u
< T )-3 >
"I
\ f / av
. A (2 w
d in 2 L , , ,
To
x IO-12
X 10~4
x io 9
I
1.3301
1.3348
8. 588
0.779
2.9 4
II
1.3263
1.3281
4 .7 5 0
1.346
3. 09
III
I . 3244
1.3256
3.139
2.198
2.87
IV
1.3338
I. 3404
0.863
1.72
V
1.3288
1.3310
7.187
1.351
2.02
VI
1.3258
1.3270
4.335
1.927
2.37
13.20
=39“
t h i a c y a n i n e s and o x a c y a n in e s r e s p e c t i v e l y , , , t h e n t h e
e f f e c t o f t h i s c o n j u g a t i o n c o u ld b e d e s c r i b e d by t h e
te r m s i n d u c t i v e e f f e c t and m eso m eric e f f e c t .
T h ese
te r m s w ere d e f i n e d by. t h e c l a s s i c a l t h e o r y o f v a le n c e
or its
quantum m e c h a n ic a l e q u i v a l e n t , v a le n c e b o n d t h e o r y .
The i n d u c t i v e e f f e c t o f a s u b s t i t u e n t i s t h e e f f e c t
o f t h e p o t e n t i a l f i e l d o f t h e s u b s t i t u e n t on t h e T f
e l e c t r o n s o f t h e u n s u b s t i t u t e d m o le c u le .
The r e p l a c e ­
m en t o f a OHg g ro u p by NH,. 0 , o r S c a n b e c o n s i d e r e d
a s an i n d u c t i v e p e r t u r b a t i o n .
N itr o g e n and o x y g e n b e in g
m ore e l e c t r o n e g a t i v e t h a n c a r b o n , o xygen e v e n m ore th a n
n i t r o g e n , w i l l t e n d t o a t t r a c t e l e c t r o n s fro m t h e r e a t o f
t h e m o le c u le .
S iric e s u l f u r h a s a n e l e c t r o n e g a t i v i t y
m ore n e a r l y t h a t o f c a r b o n , t h i s e f f e c t w i l l b e n e g l i g i b l e .
A lso s u l f u r c o u ld a cc o m o d a te a p a r t i a l p o s i t i v e c h a rg e
m ore e a s i l y ,..th a n o x y g e n . 18
The m eso m e ric e f f e c t o f a s u b s t i t u e n t i s d e f i n e d
a s t h e a b i l i t y o f t h e s u b s t i t u e n t t o e x te n d t h e s p a c e
o v e r w h ic h t h e T f
c a liz e d .
e l e c t r o n s o f t h e m o le c u le a r e d e l o ­
S in c e t h e n o n -b o n d in g e l e c t r o n s o f o x y g e n ,
n i t r o g e n , an d s u l f u r a r e pTf t y p e ,, t h e s e e l e c t r o n s
r e p e l l th e T f e le c tr o n s o f th e h y d ro ca rb o n .
T h is r e p u l ­
s io n i s due a t l e a s t in p a r t to th e E l e c t r o s t a t i c f i e l d
o f t h e -pTf e l e c t r o n s and d e c r e a s e s i n t h e o r d e r o f
=aAiOm9
oxygen, n itro g e n , s u l f u r . I n
a d d i t i o n t h e lo w l y i n g d
o r b i t a l s o f s u l f u r p o s s i b l y , p la y , some r o l e i n t h e e x ­
te n s io n o f th e c o n ju g a tio n .
R e so n a n c e s t r u c t u r e s s u c h a s th o s e i n F i g u r e 8
c a n b e draw n f o r an o p e n c h a i n c y a n i n e , . a n o x a c y a n in e
an d a th ia c y „ a n in e ..
T hose p i c t u r e d a r e f o r a s h o r t m ethy­
l e n e c h a i n l e n g t h b u t t h e same ty p e o f s t r u c t u r e s c an
b e d raw n f o r a l o n g e r c h a in w ith t h e same r e s u l t i n g
c o n c l u s i o n s ..
From th e . i n d u c t i v e e f f e c t and t h e m eso m eric
e f f e c t , an e n e rg y d ia g ra m o f t h e s t r u c t u r e s c o u ld b e
shown i n a q u a l i t a t i v e " w a y .
A ll th e s t r u c t u r e s a re c o n s id e re d to c o n tr ib u te
t o t h e dy e m olecule,,., b o t h i n t h e g ro u n d an d e x c i t e d
s ta te s .
I n 't h e . g ro u n d s t a t e , h o w e v e r, t h e r e w i l l b e
r e l a t i v e l y g r e a t e r c o n t r i b u t i o n s fro m t h e lo w -e n e rg y
e x tre m e s t r u c t u r e s w h ere t h e p o s i t i v e c h a rg e i s on t h e
n i t r o g e n ,., w h ile i n t h e e x c i t e d s t a t e t h e h i g h e r - e n e r g y
s t r u c t u r e s p la y a g r e a t e r p a r t,.
Thus t h e e n e r g y d i f f e r ­
e n c e b e tw e e n th e . g ro u n d s t a t e and t h e e x c i t e d s t a t e
i s l e s s f o r o x a c y a n in e t h a n f o r . an o p en c h a in c y a n in e ,
and even l e s s f o r th ia c y a n in e ,
E ven th o u g h a rg u m e n ts l i k e t h e p r e c e d in g , g i v e an
e s t i m a t e o f t h e e x p e c te d d i f f e r e n c e i n t h e r a d i a t i v e
l if e ti m e s o f th e s e r i e s . o f th ia c y a n in e s v e rs u s th e s e r ie s
P ossible Resonance Structures
I
&
I
I
l@
i
) Q
I
*
6
/©
N=C-C=C-N
2
N-C-C=C-N
3
N -C -C -C -N or N=C-C-C=N
I
9®
6
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/
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N-C-C=C-N
•
9
S
f
N-C=C-C-N
Y . f® :, 'X ; '
7
N-C=C-C-N- ’
'.
9
N - C-C=C-N
I Q
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f
8
4 _ N-C=C-C-N
5
I
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N-C=C-CfN'
Energy L evels of Structures
3
3
6
2
4
3
7
2
.
4
2
8
I
5
Open Chain Cyanine
E .S .
I
5
Oxacyanine
Energy L evels of Molecule
E .S.
I
Thiacyanine
E .S .______
G. S.
G. S.
G. S .______
Open Chain Cyanine
Oxacyanine
Thiacyanine
Figure 8
«3
^4*2“®
o f o x a c y a n in e a , t M y do n o t g i v e a num ber t h a t i s a c c u r a t e
t o a s i x p e r c e n t e x p e r im e n ta l, e r r o r .
To u s e t h e l i f e ­
tim e f o r s p o n ta n e o u s e m is s io n i n o t h e r c a l c u l a t i o n s
an d t o e s t a b l i s h t h e p r o p e r t i e s o f e x c i t e d s t a t e s , an
a c c u ra te f ig p r e i s needed.
I f . , t h e f l u o r e s c e n c e e f f i c i e n c i e s w ere known f o r
t h e s e d y e s .,. t h e n an o b s e r v a b l e l i f e t i m e 't ' c o u ld b e
c a l c u l a t e d w ith g o o d a c c u ra c y , e v e n .th o u g h some o f t h e s e
l i f e t i m e s a r e p r o b a b ly to o s h o r t t o m e a su re w ith known
m e th o d s , e s p e c i a l l y . t h e s h o r t c h a i n l e n g t h d y e s .
The
f l u o r e s c e n c e e f f i c i e n c i e s w ere d e te r m in e d by c o m p a ris o n
w ith known s t a n d a r d s .
F o r t h e c o m p a ris o n t o b e a c c u r a t e , , t h e raw f l u o r e s ­
c e n c e s p e c t r a w e re c o r r e c t e d f o r t h e f o l lo w in g w a v e le n g th
d e p e n d e n t f a c t o r s : . t h e quantum e f f i c i e n c y ., o f t h e p h o to ­
m u l t i p l i e r , , t h e b a n d w id th o f t h e e m is s io n m o n o ch ro m ato r
an d t h e t r a n s m i s s i o n f a c t o r o f t h a t m o n o c h ro m a to r.
T h is
was done b y r e c o r d i n g , t h e s p e c t r a o f t h e f o l l o w i n g com­
p o u n d s e x c i t e d a t 366 m/z- f o r w h ic h t h e c o r r e c t e d s p e c t r a
a r e know n?0 > 2 1 ,2 2 .
q u i n i n e b i s u l f a t e , . . I y^-g/m l i n 6 .1 N
HgSO^;. 3 - a m i n o p h t h a l i m i d e ,. I > b g /m l i n 0 .1 N HgSO^; 3 n i tro -N -, N- d im e th y l a n i l i n e ,. 100 y z g /m l i n 3.0% b e n z e n e
and. 70% h e x a n e by v o lu m e; an d 4 - d im e th y la m in o - 4 ’- n i t r o - ■
s t i l b e n e ,. .100 yxLg/ml i n o - d l c h l o r o b e n z e n e .
The v a lu e s
-4 3 -
c h o s e n w e re t h o s e g i v e n b y A rg a u e r^ 2 f o r d i l u t e s o l u t i o n s
a t 90° r a t h e r th a n th o s e o f L ip p e r t e t , a l . ^
fo r fro n t
s u r f a c e c o n c e n t r a t e d s o l u t i o n f l u o r e s c e n c e .,
The f l u o r e s ­
c e n c e s p e c t r a o f t h e s e com pounds c o v e r t h e v i s i b l e s p e c tru m .
The l e a s t r e l i a b l e r e g i o n i s t h a t l e s s th a n 4 2 5 .m/^s i n c e t h e q u i n i n e b ^ s u l f a t e f l u o r e s c e n c e i s 5.Q^ o f i t s
maximum a t t h a t w a v e le n g th an d d e c r e a s i n g a s t h e wave­
le n g th d e c re a s e s .
So a s m a ll e r r o r i p e i t h e r t h e s t a n d a r d
c u rv e o r i n t h e m e a su re d c u rv e w i l l g i v e l a r g e r e r r o r s
i n t h e c o r r e c t i o n f a c t o r a t t h e s h o r t e r w a v e le n g th s .
The s p e c t r a o f t h e com pounds o v e r l a p w ith a t l e a s t T0%
o f t h e i r maximum i n t e n s i t y e x c e p t f o r t h e r e g i o n b e tw e e n
590 an d 640 im/A w here t h e two s p e c t r a c r o s s a t 50% o f
t h e i r m axim a.
T h e .s o d iu m s a l t o f 2 , 2 '- d l h y d r o x y - l , l '-
a z o n a p h t h a l e n e - 4 - s u l f o n i c a c i d c o u ld n o t b e o b t a i n e d ,
o t h e r w i s e , i t w o u ld h a v e .b e e n u s e d ,, a s t h e f l u o r e s c e n t
alum inum c h e l a t e , , t o c o v e r t h i s r e g i o n .
Then S y i , t h e c o r r e c t i o n f o r t h e t h r e e w a v e le n g th
d e p e n d e n t f a c t o r s , , was c a l c u l a t e d fro m e q u a t i o n
(40)
"
1
w h ere ( d Q /d A ) g ^ now i s t h e known s p e c t r a l d i s t r i b u t i o n o f
o n e o f t h e s t a n d a r d com pounds a n d Rg^ i s t h e p h o t o m u l t i ­
p l i e r r e s p o n s e o f t h i s i n s t r u m e n t t o t h e same compound
u n d e r t h e same c o n d i t i o n s a s t h a t f o r w hich th e . s t a n d a r d
f l u o r e s c e n c e c u rv e i s p r o v i d e d .
The r e s u l t i n g S yl
's
-4 4 -
.a r e p l o t t e d i n F i g u r e 9.
U n c e r t a i n t y , in . t h e
The d o t t e d l i n e g i v e s a maximum
' s i n t h e r e g i o n l e s s t h a n 425. m/Z. „
The f l u o r e s c e n c e s p e c t r a o f t h e d y e s I th r o u g h VI .
an d o f t h e known com pounds q u i n i n e b i s u l f a t e an d rh o d am in e
B w ere d e te rm in e d , w ith t h e same i n s t r u m e n t c o n f i g u r a t i o n
t
a s t h a t f o r w h ich t h e S y^ ’ s w ere c a l c u l a t e d , . F o r . t h e
e n e r g y . c o r r e c t i o n u s i n g p e a k h e i g h t s , , two o f t h e compounds,
w ere e x c i t e d a t t h e same w a v e le n g th an d lam p, i n t e n s i t y .
S ee T a b le I I I f o r t h e e x c i ti n g ; ,w a v e l e n g t h s .
S in c e t h e f l u o r e s c e n c e e f f i c i e n c y ;o f some o f t h e
d y e s i s v e r y lo w ,., s o l u t i o n s w h ic h a b s o r b e d a n a p p r e c i a b l e
am ount o f t h e e x c i t i n g l i g h t h a d t o b e u s e d .
So t h a t
any c o r r e c t i o n s f o r t h i s w ould c a n c e l . f o r t h e two s o l u t i o n s
t o b e com pared,., a l l t h e s o l u t i o n s w ere made t o h a v e an
a b s o r b a n c e o f 0 . 4 p e r cm. a t t h e e x c i t i n g w a v e le n g th
■as s u g g e s te d b y P a r k e r . -*-2
The r e s u l t i n g f l u o r e s c e n c e , s p e c t r a w ere t h e n u s e d
t o d e te r m in e t h e f l u o r e s c e n c e e f f i c i e n c y o f t h e s i x
d y e s ..
T h is e n t a i l e d d i v i d i n g t h e p h o t o m u l t i p l i e r r e s p o n s e
a t e a c h 5 m^u. i n t e r v a l by, t h e c o rre s p o n d in g . Sj^
an d th e n
i n t e g r a t i n g by. t h e m ethod o f t h e sum of. t h e a r e a s o f
t h e r e c t a n g l e s fo rm ed b y t h e c o r r e c t e d r e l a t i v e i n t e n s i t y
v e r s u s t h e w a v e le n g th t o f i n d t h e a r e a u n d e r . t h e
flu o re s c e n c e c u rv e .
44
H I
Figure 9
i r" •
I
i i-
-L
I
, L-
4 H J M-
Wavdength in m yV-
TABLE I I I
E x c i t a t i o n W av e le n g th
424
Compound
. Dye I
55.6
Dye I I
65:2-
Dye
376
Dye IV
483
Dye V
57.9
Dye VI
h i
I
366
f Q u in in e 3
( D y e IV
390
/D y e IV
I D y eII
440
CDye I
I Dye V
500
/D y e V
\ Dye I I
560
/ Dye I I
LDye VI
600
/D y e VI
LDye I I I
535 .
/D y e I I
( R hodam ine B
-4 7 »
The t r u e a b s o r b a n c e s w ere d e te r m in e d f o r a l l t h e
s o lu tio n s ,.
Then b o t h t h e a r e a s a n d t h e p e a k h e i g h t s
w ere c o r r e c t e d t o 0 .4 0 0 by, a ssu m in g a l i n e a r r e l a t i o n s h i p
b e tw e e n a b s o r b a n c e an d f l u o r e s c e n c e q u a n ta .
A ll o f th e
a b s o r b a n c e s w e re w i t h i n 9 p e r c e n t o f b e in g 0 .4 0 0 ,
w ith m o st of. them v e r y c l o s e ,
so t h i s a s s u m p tio n s h o u ld
be v a lid .
The c o r r e c t i o n f o r t h e in d e x o f r e f r a c t i o n was
made f o r th e . c a l c u l a t i o n w ith Dye IV i n m e th a n o l (n —
1 .3 3 5 . fro m F i g u r e 7). an d q u i n i n e b i s u l f a t e , i n I N. H2SO^
(n =
1 .3 3 8 2^) £tnd w ith Dye. I I . i n m e th a n o l (n =
fro m F i g u r e 7 ) a n d rh o d a m in e B i n e t h a n o l (n =
1 .3 2 6
I . 3 6 0 -2^ ) .
.A l l t h e d y e s w ere d i s s o l v e d i n m e th a n o l so no c o r r e c t i o n s
had. t o b e made f o r t h e r e f r a c t i v e in d e x .
The f l u o r e s c e n c e e f f i c i e n c i e s w ere c a l c u l a t e d w ith
q u in in e b i s u l f a t e
( ^
w ith rh o d a m in e B ( 0
-
0 . 5 5 , ^ ')
0 .9 7
a s t h e s t a n d a r d and
a s th e s ta n d a rd .
The
r e s u l t s o f th e s e c a l c u l a t i o n s and th e c o r r e c te d a re a s
u n d e r t h o f l u o r e s c e n c e c u rv e s a r e g iv e n i n T a b le IV ,
As c'an b e se e n , i n T a b le IV ^ t h e
fro m t h e two s t a n d a r d s a r e d i s p a r a t e .
s as c a lc u la te d
S in c e rh o d a m in e
B h a s a v a lu e o f 5 .0 fro m q u i n i n e b i S u l f a t e , i t w ould
a p p e a r t h a t t h e p ro b le m m u st l i e
f o u r s h o r t e r c h a i n - l e n g t h d y e s ..
■
i n one o r m ore o f t h e
-4 8 =
TABLE. LV '
Compound
I n te g r a te d .
Area
;
Q u in in e
B is u lfa te
Dye I
913,
1 .9 1 .
Dye I I
491
Dye I I I
4570.
Dyp IV
5 .7 7 .
1
^ from .
Q u in in e1
B is u ifa te
(j from
. Rhodamine B
0 .5 5 .
0 .1 1
0 .0 0 3 0
0 .0 0 0 5 9
0 .2 5
0 .0 4 8
1 .7
0 .3 3
0,. 0037
0 .0 0 0 7 1
Dye V.
- 282
0 .2 7
0 .0 5 3
Dye VI
5110
2 .2
0 .4 3
Rtipdamine B .
8290
5 .0
0 .9 7 .
The i n t e g r a t e d , a r e a s a r e c o r r e c t e d f o r e v e r y t h i n g
b u t t h e lam p i n t e n s i t y , , t h e b a n d w id th o f t h e e x c i t a t i o n
m o n o ch ro m ato r and t h e t r a n s m i s s i o n f a c t o r o f t h a t mono­
c h r o m a to r .
I f i t i s assum ed t h a t t h e l a s t two f a c t o r s
a r e much s m a l l e r t h a n t h e v a r i a t i o n i n lam p i n t e n s i t y ,
t h e n t h e m a jo r c o r r e c t i o n i s t h e d e c r e a s in g , q u a n ta o f
l i g h t w ith d e c r e a s i n g w a v e le n g th fro m t h e t u n g s t e n lam p.
Now Dye I h a s ah i n t e g r a t e d a r e a o f I . .91..f o r e x c i t a t i o n
a t 424 m/6 w h ile D y e -IV h a s a n a r e a o f 5...77 . f o r e x c i t a t i o n
a t 376 mxz-, a r a t i o o f a p p r o x im a te ly 1:3..
I f th e tu n g s te n
lam p i s assu m ed t o r u n a t 3 0 0 0 ° K an d i f i t i s assum ed
t o e m it l i k e a b la c k b o d y r a d i a t o r , , t h e n a t 424 nyz. i t
w i l l e m it 2 .1 3 .X 10“ ^ e i n s t e i n s p e r
ja .
m"”1 i n t e r v a l
w h ile a t 376 m^c i t w i l l e m it 6 .7 3 . X 10” ^ e i n s t e i n s
p e r ytU-m- -*- i n t e r v a l .
3 :1 .
T h i s i s a r a t i o o f a p p r o x im a te ly
So i t w ould a p p e a r t h a t t h e
^
’ s o f D yelI t o Dye IV
s h o u ld b e a t l e a s t 1 : 3 . i f n o t g r e a t e r , b u t t h e y a r e n o t ,
th e y a r e a p p r o x im a te ly .th e sam e.
So t h e r e l a t i o n s h i p b e tw e e n Dye ..I and Dye IV , w hich
w ere c a l c u l a t e d on e from t h e o th e r,... ,would seem t o b e
a weak l i n k i n t h e c h a i n o f f l u o r e s c e n c e e f f i c i e n c y
c a lc u la tio n s .
The w a v e le n g th a t w h ic h b o t h w e re e x c i t e d
f o r c o m p a ris o n was o n e i n w h ic h n e i t h e r h a d a v e r y
l a r g e a b s o r b a n c e an d t h e energy., o f t h e lam p i s a l s o
v e r y lo w i n t h i s r e g i o n .
B etw een t h e s e f a c t s and t h e
f a c t t h a t n e i t h e r h a s a v e ry la r g e f lu o r e s c e n c e e f f ic ie n c y ,
t h e i n s t r u m e n t s e n s i t i v i t y , w;as p u s h e d t o i t s u tm o s t,
t o g i v e a v e r y s m a ll, p e a k h e i g h t .
b e i n t r o d u c e d i n t h i s m a n n e r..
Thus e r r o r c o u ld .
H ow ever e v en a l l t h i s
c an n o t e x p l a i n a n e r r o r o f a f a c t o r o f f i v e .
The d y e s I an d IV a r e d i f f e r e n t , from t h e o t h e r s
i n t h a t th e y , do n o t g i v e m i r r o r im ag e f l u o r e s c e n c e s .
—50»=»
T h is may mean t h a t t h e r e i s a m o le c u la r r e a r r a n g e m e n t
upon e x c i t a t i o n .
The f l u o r e s c e n c e e f f i c i e n c y c a l c u l a t i o n
'
:
.
'
'
'
-
, h a s t h e b a s i c a s s u m p tio n t h a t t h e f l u o r e s c e n c e , e f f i c i e n c y
i s c d n s t a n t a c r o s s t h e . a b s o r p t i o n band.:, . I f t h e r e i s ,
a m o le c u la r, r e a r r a n g e m e n t i n t h e e x c i t e d s t a t e ; , , p e rh a p s
some e x c i t a t i o n e n e r g i e s a r e m ore f a v o r a b l e f o r e m is s io n
th a n o th e r s .
E x c i t a t i o n t o some p a r t i c u l a r v i b r a t i o n a l
l e v e l s m ig h t r e a r r a n g e m ore r e a d i l y , and. t h e n f l u o r e s c e
r a t h e r th a n decay r a d i a t i o n l e s s l y .
Thus t h e f l u o r e s c e n c e
e f f i c i e n c y may n o t b e a c o n s t a n t a c r o s s t h e a b s o r p t i o n
band.
Then t h e b e s t f l u o r e s c e n c e e f f i c i e n c i e s may b e
t h o s e i n which.. Dye. .I. a n d . Dye IV a r e c a l c u l a t e d m o st
d i r e c t l y fro m a .known, s t a n d a r d , a n d n o t from e a c h o t h e r .
T h is g i v e s a r a t i o o f
^ *s o f a p p r o x im a te ly 1 : 6 f o r
Dye . I t o . D y e 1I V .
^ ' s fro m t h i s a s s u m p tio n w ith
The
t h e i r e s tim a te d e r r o r s , th e o b s e rv a b le l i f e t i m e s .c a l c u ­
l a t e d fro m t h e s e
(j> ' s and t h e c a l c u l a t e d i n t r i n s i c
l i f e t i m e s a r e su m m arized i n T a b le V,
The l a r g e r e r r o r
i n Dye IV com es fro m t h e u n c e r t a i n t y , i n
w h ile t h e
e r r o r i n D y e. I comes, fro m t h e u n c e r t a i n t y i n r e a d i n g
th e c u rv e .
The e r r o r f o r t h e o t h e r f o u r d y e s i s a s s e s s e d
a t t h e n o m in a l 10 p e r c e n t f o r t h i s p r o c e d u r e s i n c e
th e r e i s n o t th e u n c e r ta in ty in
an d s i n c e t h e
-5 1 -
TABLE V
Dye
I
0.00059..
II
0.048
III
0.33
_'IV
0.0037
V
0.053
VI
0.43.
T
, r 0
<f>
2. 94 X 10-9
1.7. X dO”12.
10#
3.09 X io-9
1.5.X 10~10
10#,
2.8? X 10“9
9.5 X 10-10
1.72 X IO^9
6,4 X 10-12
2.02 X 10“9
1.1 X ib-i°
2.37 X lO""9
1.0 X 10-9
20#
!-
50#
10#
10#
s t a n d a r d rh o d a m in e B h a s i t s
f l u o r e s c e n c e i n t h e same
re g io n a s th e s e d y es.
The f l u o r e s c e n c e e f f i c i e n c i e s v a ry m o st by. c h a in
l e n g t h i n t h e two s e r i e s o f d y e s .
in c re a s e s ,
As t h e c h a i n l e n g t h
so d o e s t h e f l u o r e s c e n c e 1e f f i c i e n c y .
..The ,
p r e d i c t e d , o b s e r v a b l e l i f e t i m e s v a r y i n t h e sam e m an n er.
S m a ll d i f f e r e n c e s b e tw e e n t h e two s e r i e s f o r t h e same
c h a in l e n g t h dy e f o r t h e f l u o r e s c e n c e e f f i c i e n c y an d t h e
i n t r i n s i c l i f e t i m e s c a n c e l each o th e r o u t to g iv e
a p p r o x im a te ly t h e same p r e d i c t e d o b s e r v a b l e l i f e t i m e s
e x c e p t f o r t h e s h o r t e s t m em bers.
Dye I i s m ore crow ded
and t h u s may b e e x p e c te d t o b e d i f f e r e n t fro m Dye I'y .
-5 2 -
The r a t e o f a l l d e c a j p r o c e s s e s i s t h e i n v e r s e o f
t h e o b s e r v a b le , l i f e t i m e s so t h a t f o r s h o r t e r l i f e t i m e s
th e r a t e i s f a s t e r ..
The r a t p o f e n erg y , t r a n s f e r m ust
co m p ete w ith t h i s f l u o r e s c e n c e r a t e t o b e e f f e c t i v e .
I f t h e r a t e o f e n e rg y t r a n s f e r i s t h e same f o r a l l th e
d y e s , . t h e n i t w ould a p p e a r t h a t t h e l o n g e r t h e c h a i n
l e n g t h t h e m ore e a s i l y t h e e n e r g y t r a n s f e r c o u ld co m p e te .
T h is c o r r e l a t e s v e r y w e ll w ith t h e f a c t t h a t t h e l o n g e r
t h e c h a i n l e n g t h t h e b e t t e r t h e dye s e n s i t i z e s
p h o t o g r a p h i c f i l m s . 2®Dyes o f t h e 3 , 3 ’ - d i e i b h y l t h i a c y a n i n e s e r i e s i n
h i g h c o n c e n t r a t i o n s d im e r iz e i n w a te r s o l u t i o n s ,
No
e v id e n c e o f d im e r f o r m a t io n i n o r g a n i c s o l v e n t s a t
room t e m p e r a t u r e h a s b e e n r e p o r t e d . 2^
The f o l l o w i n g
s t u d i e s w ere done t o c h e c k f o r t h e p o s s i b i l i t y o f d im e rs .
The o r i g i n a l d y e s o l u t i o n s p r e p a r e d f o r t h e e m is s io n
s p e c t r a w ere a lm o s t s a t u r a t e d . s o l u t i o n s ; t h a t i s , , a b o u t
1 0 “ ^ M f o r Dyes I I I and. VI an d a b o u t 1.0"^ M f o r t h e o t h e r
fo u r d y es.
T h ese s o l u t i o n s p l u s d i l u t i o n s o f 10""®,
10” ^ an d 1 0 “ ^ M f o r Dyes I I I a n d -VI and d i l u t i o n s o f 10"\
10” ®. a n d 10” ® M-*-for t h e o t h e r d y e s w ere s t u d i e d
f o r d i f f e r e n c e s o f sh a p e o f t h e e m is s io n s p e c tr u m .
T h ese s o l u t i o n s w ere a l s o s t u d i e d f o r v a r i a t i o n s , o f
t h e e m is s io n s p e c tru m upon e x c i t a t i o n by. d i f f e r e n t
-
e x c i t i n g w a v e le n g th s .
53 -
T hose w a v e le n g th s u s e d w ere
t h e maximum o f t h e a b s o r p t i o n b a n d , t h e a p p ro x im a te
maximum o f t h e a b s o r p t i o n s h o u l d e r , , t h e d im e r w a v e le n g th
a s r e p o r t e d b y W est and P e a r c e ^ , , and a l o n g e r w a v e le n g th
th a n t h e a b s o r p t i o n maximum.
The m a jo r c h a n g e i n t h e e m is s io n s p e c tru m o f a l l
s i x d y e s upon a d e c r e a s e i n t h e c o n c e n t r a t i o n o f t h e
dye w a s . a n i n c r e a s e i n t h e r e l a t i v e h e ig h t, o f t h e m a jo r
p e a k v e r s u s t h e s h o u l d e r an d a - s h i f t i n t h e maximum
o f t h e m a jo r p e a k to w a rd s h o r t e r w a v e le n g th s .
The
w e a k e s t two c o n c e n t r a t i o n s g a v e e s s e n t i a l l y , t h e same
s p e c tru m w ith o n l y m ore n o i s e i n t h e w e a k e r .o n e .
T h is
c h a n g e w ith d i l u t i o n may b e a t t r i b u t e d a t . l e a s t i n p a r t
to . s e l f - a b s o r p t i o n o f t h e s h o r t e r w a v e le n g th e m i t t e d
l i g h t b y t h e m ore c o n c e n t r a t e d s o l u t i o n s .
W ith t h e m o st c o n c e n t r a t e d s o l u t i o n o f dye, e x c i t a t i o n
a t a w a v e le n g th l o n g e r th a n t h e a b s o r p t i o n maximum g a v e
a s p e c tru m i n w h ich t h e s h o u l d e r t o maximum p e a k h e ig h t h
r a t i o was l a r g e r t h a n t h a t f o r e x c i t a t i o n a t o t h e r
w a v e le n g th s .
T h is anom aly, was n o t o b s e r v e d i n a n y o f
t h e m ore d i l u t e s o l u t i o n s .
S in c e d im e rs h a v e b e e n
r e p o r t e d i n w a te r s o l u t i o n s ^ , . a s a t u r a t e d s o l u t i o n
o f Dye I I I was p r e p a r e d .
The a b s o r p t i o n s p e c tru m g a v e
a p p r o x im a te ly e q u a l h e i g h t s f o r t h e monomer an d d im e r
-
.a b s o r p t i o n p e a k s .
54 -
The e m is s io n , s p e c tru m o f t h i s s o l u t i o n
h a d t h e p e a k maxuma a t . t h e same w a v e le n g th s a s t h e d i l u t e
m e th a n o l s o l u t i o n s . • T h is c o u ld - p o s s i b l y , b e e x p l a i n e d
by. t h e f a c t t h a t t h e e x t i n c t i o n c o e f f i c i e n t s f o r t h e
w a te r s o l u t i o n a r e much lo w e r t h a n f o r t h e m e th a n o l
s o lu tio n o f s im ila r c o n c e n tr a ti o n s o
le s s s e lf-a b s o rp tio n .
t h e r e m ig h t, b e
D i f f e r e n t e x c i t i n g w a v e le n g th s
d i d n o t c h a n g e t h e p e a k h e i g h t r a t i o s i n t h e w a te r
s o lu tio n .
So w h e th e r d im e rs w ere t h e c a u s e o f t h e anom aly
i n t h e c o n c e n t r a t e d m e th a n o l s o l u t i o n s i s s t i l l a moot
q u e s tio n .
I n any. c a s e t h e c o n c e n t r a t i o n s o f d y e s u s e d
f o r t h e a b s o r p t i o n an d e m is s io n s t u d i e s w ere d i l u t e
en o u g h t o g i v e no e v id e n c e o f t h e p r e s e n c e o f d im e rs
o r s e lf-a b s o rp tio n s
SUMMARY
The a b s o r p t i o n an d e m is s io n s p e c t r a i n m e th a n o l
o f t h e d y es, o f t h e 3 , 3.1r d i e th y l t h l a c y a n i n e i o d i d e s e r i e s
an d o f t h e 3>3.!- d i e t h y l p x a c y a n i n e i o d i d e s e r i e s
f o r t h e f i r s t member w h ich was t h e t r i i o d i d e )
d e te r m in e d .
(e x c e p t
w ere
The i n t e g r a t e d i n t e n s i t i e s and o s c i l l a t o r
s t r e n g t h s w ere c a l c u l a t e d .
In each s e r ie s th e s e
q u a n t i t i e s i n c r e a s e a s t h e m e th y le n e c h a in l e n g t h
in c re a s e s .
From t h e a b s o r p t i o n an d e m is s io n s p e c t r a ,
t h e r a d i a t i v e l i f e t i m e s w ere c a l c u l a t e d . .
The l i f e t i m e s
w ere o f t h e o r d e r o f t h r e e n a n o s e c o n d s f o r t h e t h i a c y a n in e s e r i e s an d o f t h e o r d e r o f two n a n o s e c o n d s
f o r t h e o x a c y a n in e s e r i e s .
w ere, d e te r m in e d .
The f l u o r e s c e n c e e f f i c i e n c i e s
T hey i n c r e a s e b y ,a f a c t o r o f t e n . a s
t h e c h a i n l e n g t h i n c r e a s e s e x c e p t f o r t h e f i r s t member
o f t h e s u l f u r s e r i e s w h ich , i s lo w e r by a f a c t o r o f
100 fro m t h e n e x t m em ber.
The o b s e r v a b le , l i f e t i m e s
w e re c a l c u l a t e d fro m t h e r a d i a t i v e l i f e t i m e s a n d t h e
flu o re s c e n c e e f f i c ie n c i e s .
S in c e t h e r a t e o f a l l d e c a y
p r o c e s s e s i s th e in v e r s e o f th e o b s e rv a b le l i f e t i m e ,
a minimum may b e p l a c e d on t h e r a t e o f e n e rg y t r a n s f e r
fro m t h e f i r s t e x c i t e d s t a t e f o r t h e s e d y e s when e n e rg y
t r a n s f e r p ro c e s s e s ta k e p la c e .
-
55 -
EXPERIMENTAL
M e ltin g , p o i n t s w ere d e te r m in e d on a F is h e r , m e ltin g
p o i n t b l o c k an d w ere u n c o r r e c t e d .
A n a ly s e s w ere p e rfo rm e d by G a l b r a i t h L a b o r a t o r i e s ,
I n c o r p o r a te d ,.. P . 0 . Box 4 1 8 7 - L o n s d a le , . 2323 Sycam ore
D r iv e , K n o x v ille ,.. T e n n e s s e e 3 7 9 2 1 .
The u l t r a v i o l e t an d v i s i b l e a b s o r p t i o n s p e c t r a
w ere t a k e n on a Beckm an M odel DK=2 s p e c t r o p h o t o m e t e r
f o r 1 , 1 ’ ,.3 ,3 ., “ t e t r a e t h y lb e n z i m id a z o l .o c a r b o c y a n i n e i o d i d e
an d o n a . C a r y . Model. 1.4 s p e c t r o p h o t o m e t e r f o r a l l t h e
o th e rs .
The e m is s io n s p e c t r a w ere t a k e n on _a com ponent
s y s te m .
T h is c o n s i s t e d o f a t u n g s t e n Iainpi, two B au sch
an d Lomb C a t. No. 3 3 -8 6 -4 5 m o n o ch ro m ato rs w ith t h e
g r a t i n g b l a z e d a t 3000 SL9 an EMI M odel 9558 B p h o to ­
m u l t i p l i e r , . and a H e w le tt P a c k a r d M odel M o seley ,7,030A
X-Y r e c o r d e r .
M eth an o l,.. B a k e r A n a ly ze d a b s o l u t e , w i t h o u t f u r t h e r
p u r i f i c a t i o n was t h e s o l v e n t f o r t h e cy .an in e d y e s o l u t i o n s
. . .
..
<
f o r a b s o r p t i o n and f l u o r e s c e n c e .
I t h a d no d e t p e t a b l e
flu o re s c e n c e i
E t h a n o l , 9 5 $ , was u s e d w i t h o u t f u r t h e r p u r i f i c a t i o n .
I t h a d no d e t e c t a b l e f l u o r e s c e n c e .
“56-
*=57“
o - D i c h lo r o b e n z e n e . B a k e r A n a ly z e d r e a g e n t ,,, c o n t a i n e d
no f l u o r e s c i n g , s p e c i e s , B .p„ 1 8 0 .3 - 1 8 0 .5 ° a t 640 mm,
B e n z e n e , B a k e r A n a ly z e d , was d r i e d o v e r so d iu m and
d i s t i l l e d , , b . p . 7 2 ^ 8 -7 3 ° a t 640 mm.
H e x a n e , B a k e r .A n a ly z e d , was p u r i f i e d w ith c h l o r o s u lfo n ic a c i d . A b o u t
1
■
1
400 ml., o f t h e h e x a n e was ad d ed
■
t o 80 ml o f E a stm a n p r a c t i c a l c h l o r o s u l f o n i c a c i d i n
a 3 - n e c k e d on e l i t e r ro u n d b o tto m f l a s k .
A f te r th e
a d d i t i o n , two o f t h e n e c k s w ere s to p p e r e d ,, t h e t h i r d
h a d a v e n t tu b e t o a llo w t h e / e s c a p e o f t h e h y d ro g e n
c h l o r i d e fo rm e d d u r i n g t h e r e a c t i o n .
The r e a c t i o n
m ix tu r e was s t i r r e d by a g l a s s - c o v e r e d m a g n e tic s t i r r i n g
b a r.
A f t e r f o u r d a y s t h e m ix tu r e was p l a c e d i n a
s e p a r a t o r y f u n n e l an d t h e a c i d la y e r,... a d a rk b ro w n ,
d ra in e d o f f .
The h y d r o c a r b o n l a y e r , . , a l i g h t y e ll o w ,
was w ash ed w ith 150 m l. o f IO ^ NaOH i s s m a ll p o r t i o n s .
■
■
: 1
'
'
Then i t was w ash ed t h r e e t im e s w ith 100 m l. o f d i s t i l l e d
■:
'
w a t e r .a n d l e f t t o d r y o v e r . Na2SO^. The h e x a n e was th e n
d r i e d o v e r sodium a n d d i s t i l l e d , b . p . 6 1 .8 - 6 2 ° a t 640 mm.
S u l f u r i c a c i d , 0 .1 N and I N,„ w ere p r e p a r e d from
I
'
D uPont R e a g e n t G ra d e c o n c e n t r a t e d s u l f u r i c a c i d and
■'
'
■ .
'
w ere s t a n d a r d i z e d a g a i n s t , s t a n d a r d NaOH,
Q u in in e B i s u l f a t e , . E astm an ,., g a v e a n 0 . D. .'.Of Q. 3.68/cm.
f o r . a c o n c e n t r a t i o n o f 0 ,0 0 5 8 8 9 g , /1 0 0 . m l. co m p ared
58 -
-
t o 0 .0 0 6 2 /c m . f o r a c o n c e n t r a t i o n o f I ^ g , / m l . f o r
P a rk e r, a n d R e e s .^
R hodam ine B#l J . T. B a k e r C h e m ic a l C o . , h a d . a n e x t i n c :
c
:
t i o n c o e f f i c i e n t o f 1 .0 6 X ICr a t 544 m/x_ compared to
1 .0 4 X 10.5 f 0 r p o r k e r and R e e s. ^
3 - A m in o p h th a lim id e , E astm an ,, was f i l t e r e d h o t and
t h e n r e c r y s t a l l ! z e d t h r e e t im e s fro m 95% e t h a n o l ..
S in c e
i t s u b lim e s a t 640 mm. t h e m e l t i n g p o i n t s w e re d e te r m in e d
u s in g , a s e a l e d , c a p i l l a r y , , tu b e an d a T h ie le tu b e f i l l e d
w ith c o n c e n t r a t e d H^SO^, m .p . 2 5 9 .5 ° ( L i t . 20 2 6 0 ° ) ,
S c*
'
X 103.
.3 7 H it^ o - U .,N - d im e th y la n ilin e ,.. P f a l t z and B a u e r ,
I n c . , was r e c r y s t a l l i z e d o n c e fro m 9 5 ^ ,e t h a n o l , m .p .
59-60° ( L i t . 20 59-60°),
€
= 1,30.x IO 3 .
4 - D im e th y la m in o .-4 $ -n it r o s t i l b e n e ,.. E a stm a n , g a v e
a v e r y . s h a r p 'm e ltin g p o i n t , , m. p.
265° ( L i t . 20 2 5 6 ° ) ,
366: = 5 .6 7 X lO ? .
"P r e p a r a t i o n o f 3 - E th y l- 2 - m e th y I b e n z o t h la z o l i u m I o d i d e
E t h y l i o d i d e ( 2 0 .0 g , ,. 0 .1 2 8 m o le s) a n d 2 - m e th y lb e n z o t h i a z o l e ( 1 0 .0 g . , 0 .0 6 7 2 m o le s w ere r e f l u x e d
t o g e t h e r f o r f o u r h o u r s ,.
A y e llo w is h -w h ite p r e c i p i t a t e
-5 9 -
fo rm e d .
A f t e r t h e r e a c t i o n : - m i x t u r e was c o o le d , th e
p r e c i p i t a t e was f i l t e r e d an d was w ashed t h r e e tim e s
w ith a c e to n e ( a b o u t 10 m l. e a c h tim e )..
The y i e l d o f
w h ite s a l t was 1 2 , 2 g.' (0 .0 4 0 0 m o le s ) ,.
P r e p a r a t i o n o f 5 - E th y l- 2 - m e th y lb e h z 6 x a z o llu m I o d i d e
E t h y l i o d i d e ( 1 8 .1 g .
0 .1 1 6 m o le s) an d 2 - m e th y l-
b e n z o x a z o le ( 8 . 2 g .,. 0 .0 6 1 4 m o le s ) w ere r e f l u x e d
t o g e t h e r f o r 47 h o u rs ;.
The r e s u l t i n g y e llo w -b ro w n
s o l i d , when, c o o le d ,, was f i l t e r e d
a n d was w ash ed t h r e e
t im e s w ith a b o u t 10 m l. p o r t i o n s o f a c e to n e .
o f p a l e . y e l l o w s a l t was 7 .7 g .
The y ie ld ,
(0 .0 2 6 7 m o le s ) .
P r e p a r a t i o n o f I . 3 - D i e t h y l - 2 - m e t h y I b e n z im id a z o liu m I o d i d e
.
■
■
'■
E t h y l I o d i d e ( 1 0 .0 0 g . ,. 0 ,0 6 4 0 m o le s) a n d 1 - e t h y l 2 - m e th y ! b e n z im id a z o le ( 7 .0 0 g..1, 0 ,0 4 3 7 m o le s) w ere
r e f lu x e d to g e th e r f o r n in e h o u rs .
The r e a c t i o n m ix tu r e
was a llo w e d t o c o o l a n d t h e n was p o u re d i n t o e t h e r .
The e t h e r s o l u t i o n was f i l t e r e d .
T h e .s o lid s a lt.w a s
w ash ed w i t h e t h e r ( a b o u t 5 m l .) a n d w ith a c e to n e ( a b o u t
5 ml.).
The y i e l d o f g r e y - y e l lo w s o l i d was 1 2 .8 g .
(0 .0 4 0 5 m o le s ) ; m .p . 1 9 9 -2 0 2 ° .
A n a l. . O a lc d . f o r •C12H iy IN 2 s
0 , 4 5 .6 ; H,„ 5 ,3 7 ;
N,. 8 .8 5 .
Found:
Cs 4 5 ,7 0 ; H, 5 .3 9 ;
N ,, 8 .9 2 . ■
P r e p a r a t i o n o f 3 . 3 ' - D l e .t h y l th i a o a r b o o y a n in e I o d i d e .
, T r i e t h y l o r t h o f d r m a te ( 1 .0 0 g . s . 0 .0 0 6 7 5 m o le s)
an d 3 - e t h y l - 2- m e th y lb e n z o th ia z o liu m io d id e . ( l f* 00 g . ,
0 .0 0 3 2 8 m o le s) w e re h e a t e d t o g e t h e r i n 10 m l. o f
p y r i d i n e w ith m a g n e tic s t i r r i n g .
When t h e m ix tu r e
r e a c h e d r e f l u x t e m p e r a t u r e an d a l l t h e s o l i d h a d
d i s s o l v e d , s i x d r o p s o f t r i e th y la m in e w ere a d d e d .
t h i s tim e t h e s o l u t i o n t u r n e d v e ry , p u r p le ..
A t.
The s p l u t i o n
was r e f l u x e d f o r te n ia m in tite s ' an d t h e n a llo w e d t o c o o l.
The c o o k e d m ix tu r e was p o u re d i n t o a b o u t 100 m l, o f
e t h e r » th o r o u g h ly m ixed a n d t h e n f i l t e r e d .
The c ru d e
y i e l d was 1 ,2 g . R R e c r y s t a l l i z a t l o n from m e th a n o l t h r e e
tim e s g a v e 0 .3 0 g . • ( 0 .0 0 0 6 0 9 m o le s ) o f shtjny. g r e y - p u r p l e
n e e d l e s ; m .p ; 267° w i t h d e c o m p o s itio n ,
, A n a l,
C a lc d . f o r C2 i H21I ^ 2 S 2 !
C> 5 1 .2 ; H, .4 .2 7 ;
I,
Found:
2 5 .8 ; .- S,. 1 3 .0 4 .
C, 5 0 .9 6 ; H, 4,32;;
I,
2 6 .0 7 ; S , 1 3 .2 6 ..
P r e p a r a tio n o f .5 .3 - - B ie th y lth ia d ic a r b o o v a n ih e Io d id e
P y rid in e
(10 m l , ) , 3 - e t h y I - 2 - m eth y I b e n z o t h i a z o I i urn
i o d i d e ( 1 .0 0 g ; , . 0 .0 0 3 2 8 m o le s ) an d I , I , 3 , I r t e t r a e t h o x y -
-6 1 -
p ro p a n e (1 ,5 2 . & ., 0 .0 0 6 8 1 m o le s) w ere h e a t e d t o g e t h e r
u n t i l a l l o f t h e s o l i d h a d d i s s o l v e d ..
t r i e t h y I am ine w ere a d d e d .
to a b lu e .
■Two d r o p s o f
I m m e d ia te ly t h e c o l o r ch an g e d
T h is m ix tu r e was r e f l u x e d f o r t e n m ore
m in u te s a f t e r w h ic h i t w as a llo w e d t o c o o l.
T hen i t was p o u re d i n t o a b o u t I 50 m l, o f e t h e r
a n d .w a s s t i r r e d w e l l .
N e x t t h e c ru d e dye was f i l t e r e d
a n d r e c r y s t a l l i z e d from m e th a n o l t h r e e t im e s t o g iv e
0 .2 0 g .
(0 .0 0 0 3 8 6 m o^es). o f s h in y y e ll o w - g r e e n m a tte d
c r y s t a l s ; m .p . 2 5 4 -6 ° w ith d e c o m p o s itio n .
A n a l.
O a lc d . f o r C23H23II<r2S 2 i
C’ 5 3 .3 ; H». 4 ..44;
I , . 2 4 .5 ; S , 1 2 ,6 2 .
Found?.
C, 5 2 .3 7 ; H,. 4 .4 4 ;
I,
2 5 .2 9 ; S , 1 2 .4 7 .
P r e p a r a t i o n o f. 3 »31- D l e t h y l o x a c y a n l n e T r i l o d l d e
The m eth o d u s e d was p r i n c i p a l l y t h a t . o f F i s h e r
an d H a m e r ^ .
The q u a te r n a r y , s a l t 3 - ©th y I - 2- me t h y I -
b e n z o x a z o liu m i o d i d e ( 3 .5 0 g . ,.. 0 .0 1 2 1 m o le s) w as1 added
t o 25. m l, o f p r o p i o n i c a n h y d r id e w h ich h a d b e e n h e a t e d
to 1 3 5 °.
A ll o f t h e s o l i d d i s s o l v e d when f r e s h l y d i s t i l ­
le d ls o p e n ty l n i t r i t e
a t 640 mm.)
( 1 .5 m l . , 0 .0 1 1 m o le s ; b .p ._ 88- 89°
was a d d e d s lo w ly .
a llo w e d t o c o o l .
Then t h e m ix t u r e was
The s o l i d w h ich f i r s t fo rm e d was an o r a n g e c o l o r .
The s o l u t i o n was d e c a n te d a n d a p u r p l e p r e c i p i t a t e
f o r m e d ,,. B p th . o f t h e s e p r e c i p i t a t e s w ere - f i l t e r e d ,
g ro u n d w i t h . w a t e r an d w ith e t h e r a n d f i l t e r e d a g a i n .
E ach y ie ld e d 0 . 2 . g. o f s o lid .
The u l t r a v i o l e t an d v i s i b l e s p e c tru m was t a k e n o f
e ach ..
The o r a n g e s o l i d a p p e a r e d t o h a v e some o f. t h e
q u a te rn a ry s a l t p r e s e n t and th e p u rp le h ad a l a r g e r
l e a d i n g edge, t o t h e dy e a b s o r p t i o n b a n d , o t h e r w i s e th e y
seem ed t h e sam e.
The p u r p l e s o l i d was e x t r a c t e d t h r e e m ore tim e s
w i t h a b o u t 20 ml., o f e t h e r e a c h t im e .
T h is p u r p l e
compound h a d a m . p . o f ' 300—1° w i t h d e c o m p o s itio n .
A n a l,
p a le d , f o r
5 5 .4 ,
2®2 l
Found:
I,
5 5 .2 1 .
A tte m p ts w ere made t o r e d u c e t h e t r i i o d i d e to
th e io d id e s a l t .
The t r i i o d i d e w as s u s p e n d e d i n 10
ml', o f m e th a n o l c o o le d i n a n i c e b a t h and t a n k s u l f u r
d i o x i d e g a s was b u b b le d t h r o u g h f o r s i x h o u r s a n d
f o r tw e n ty h o u rs.,.
The dy e t u r n e d , l i g h t e r - in c o l o r
b u t upon s t a n d i n g w ould t u r n d a r k a g a i n .
•Then t h e dy e was r e c r y s t a l l i z e d from m e th a n o l,
w ith , l i t t l e
d i f f i c u l t y t h e f i r s t tim e . . A f t e r t h e dye
d i s s o l v e d i n t h e s e c o n d r e c r y s t a l l i z a t i o n . a foam y
-6 3 -
y e llo w s u b s ta n c e fo rm e d w h ic h h a d some p u r p l e s p e c k s
in i t .
T h i s .y e l l o w s u b s ta n c e was n o t s o l u b l e i n w a t e r ,
m e th a n o l o r d im e th y lfo rm a m id e .'.
I t was s l i g h t l y s o l u b l e
i n e t h e r , much m ore so t h a n t h e p u r p l e m a t e r i a l .
P r e p a r a t i o n o f 3 , 3 ' - D le t h y l o x a c a r b o c y a n i n e I o d i d e
T r i e t h y l o r t h o f o r m a te ( 3 .2 0 g
. 0 . 0 2 1 6 m o le s)
an d 3 - e t h y l - 2-m e th y I b e n z o x a z o liu m i o d i d e (3 .0 4 8 0 g . ,
0 .0 1 0 5 5 m o le s) w e re a d d e d t o 5.0 m l. o f p y r i d i n e i n
a 20 cm. by 2 .5 cm. t e s t t u b e .
o v e r a s m a ll f la m e .
T h is m ix tu r e w as h e a t e d
.When t h e s o l u t i o n b o i l e d a t o t a l
o f 21 d r o p s o f t r i e th y la m in e was a d d e d .
The s o l i d
n e v e r seem ed .to d i s s o l v e ; h o w e v e r, when t h e s o l u t i o n
was c o o le d an d f i l t e r e d , . s h in y p u r p le - p in k , c r y s t a l s
w e re f o u n d .
T h ese w ere r e e r y s t a l l ! z e d fro m e t h a n o l
t w i c e t o y i e l d 0 , 5,5 g .
(0 ,0 0 1 2 m o l e s ) ; m .p . 2.8 1 ° w ith
d e c o m p o s itio n .
■ A n a l. . O a Ic d . T o r C21H21IN 2O2 :
0 , 5 4 .8 ; H,' 4 .'5 6 ;
I.,, 2 7 .6 .
. Found:
0 , 5 4 .6 9 ; H,. 4 .7 6 ;
I,
2 7 .4 6 .
, P r e p a r a t i o n o f 3 , 3 1Z-D ie th y I o x a d i c a r b o c y a n in e I o d i d e
A bout 0 .1 g .
( 0 .0 0 0 4 m o le s ) o f 3 - e t h y l - 2- m e th y l-
=64«=
"b en zo x azo liu m i o d i d e , a b o u t t h e same volum e o f 1 , 1 , 3 , 3te tra e th o x y p ro p a n e
( a p p r o x im a te ly 0 . 2 g . , 0..0009 m o le s)
a n d a b o u t two m l. o f d im e th y lfo rm a m id e w ere h e a t e d
t o g e t h e r i n , a IS ecm . b y 1 , 5 . cm... t e s t tu b e o v e r a s m a ll
f la m e .
When t h e s o l u t i o n s t a r t e d b o i l i n g , f i v e d ro p s
o f p y r i d i n e w e re a d d e d .
The m ix tu r e was a llo w e d t o
c o o l an d t h e n p o u re d , i n t o a b o u t 150 m l. o f e t h e r and
m ix ed w e l l .
T h is m ix tu r e w a s .a llo w e d to s t a n d f o r s e v ­
e r a l h o u r s w ith o c c a s i o n a l m ix in g .
Then t h e e t h e r was
d e c a n te d , f r e s h e t h e r a d d e d and t h e same p r o c e s s c o n tin u e d
u n t i l t h e d y e was no l o n g e r s t i c k y .
Then t h e d y e was
r e c r y s t a l l i z e d t h r e e tim e s fro m m e th a n o l,.
The above
p r o c e d u r e was r e p e a t e d f o u r t im e s t o y i e l d a t o t a l o f
0 .1 0 g .
( 0 .0 0 0 2 1 m o le s ) o f s i l v e r - t u r q u o i s e c r y s t a l s ;
m .p . 2 5 4 -6 ° w ith d e c o m p o s itio n .
,A nal..
C a lCd. f o r Cg^Hg^lNgOg.;
C,: . 5 6 . 8 ; H ,: 4 ,7 3 ;
I , 26.1;
Found:
O9 5 2 ,1 3 ; H, 4 .4 2 ;
I ,r 3 2 .1 0 .
.A 'S am ple o f 3 . 3 ' - D l e t h y l t h i a c y a n l n e lo d l& e
T h is y e llo w d y e p r e v i o u s ly , p r e p a r e d i n t h i s l a b o r a ­
t o r y g a v e s a t i s f a c t o r y a n a l y s i s w ith m. p. a b o v e 315° .
-6 5 -
A n a l.
G .aled, ,fo r G^gH1 ^IN 2S
C9 4 8 .9 ; H, 4 .0 8 ;
I 9 2 7 .2 ; S 9 1 3 .7 5
Found:
G, 48.'85.; H, 4 .2 1 ;
I,
2 7 .0 3 ; S , 1 3 .8 4 .
I
A tte m p te d P r e p a r a t i o n o f l . l >.5 .3 .l - T e t r a e t h y l b e n z l m l d a z o lo c a r b o c y a n in e I o d i d e
. An e q u a l volum e o f 1 , 3 - d i e t h y l - 2-m e th y I b e n z i m i d a z o liu m i o d i d e an d t r i e t h y l o r t h o f o r m a te w ere r e a c t e d
to g e th e r i n a s e r i e s o f s o lv e n t and b a se p a i r s .
T hese
in c lu d e d , p y r i d i n e an d t r i e t h y l a m i n e , dim e t h y I f ormami de
* an d t r i e t h y l a m i n e , n i t r o b e n z e n e a l o n e , n i t r o b e n z e n e
a n d t r i e t h y l a m i n e , n i t r o b e n z e n e an d 2 , 2 ^ , 2 " - n i t r i l o t r i e t h a n o l , ' d im e th y lfo rm a m i.d e a n d sodium h y d r o x i d e ,
a n d f i n a l l y n i t r o b e n z e n e and 3 H sodium e t h o x i d e ..
The
p ro d u c t o f t h i s l a s t r e a c tio n a f t e r fiv e r e c r y s t a l l i z a ­
t i o n s fro m m eth an o l, h a d a n e x t i n c t i o n c o e f f i c i e n t o f
51 a t t h e maximum o f 486 m /h so. i t a p p a r e n t l y was n o t
v e ry p u re .
I
BIBLIOGRAPHY
1.
A. W. Hofm ann, B e r . 2 0 . ; 2262 (1 8 8 7 ).
2.
H. W., V ogel,. B e r . , . . 6,,.,.1302 ( 1 8 7 3 ).
3.
W. H.. M ills ,.. J .. Ohem. . S o c . . 1 2 1 .. 455. (1 9 2 2 ).,
4.
N. I . ' F i s h e r an d F.. -M.. Hamer,. P ro c .. Roy,. Soe..
( L o n d o n ) . . A . 1 5 4 . 70 3 ( 1 9 3 6 ).
5..
L / J . E. H o f e r , R. J., G r a b e n s t e t t e r .,. an d E. 0 . W iig ,
J.. Am. Chem. S o c . , 7 2 . 203.. (1950)..
6.
U, M a z z u c a to , G.' F a v a r o , an d M, P., M a z z u e a to , R ic .
S c i . R e n d ., 2 4 , No. 5 , 501 ( 1 9 6 4 ).
7.
J . N. M u r r e l l , The T h eo ry o f t h e E l e c t r o n i c S p e c t r a
o f O rg a n ic M o le c u le s . J o h n W iley and S o n s ,.vN ew ;Y ork,
8.
C, S a n d o r f y , E l e c t r o n i c S p e c t r a and Quantum C h e m is tr y .
P r e n t i c e & H a l l , .I n c . , E nglew ood C l i f f s , . New J e r s e y ,
1 9 6 4 , p p . . 90, 1 0 0 -1 0 3 .
9.
S .. J ,. S t r i c k l e r an d R, ,A.. B e rg , J... Chein. P h y s .,
, 2 Z , 814 (1962) an d a s m o d if ie d b y J . B. B i r k s and
D. J . D yson, P r o c . Roy,. Soc.., ( L o n d o n ) A , 2 7 5 ,
135 ( 1 9 6 3 ) .
10.
G. A. P a r k e r , P hoto lu m in e s c e n c e o f S o l u t i o n s .
E l s e v i e r P u b l i s h i n g , C o . , New Y o rk , 1 9 .6 8 ,'p . 261.
11. -
Ibid. ,
p
.2 6 2 .
12.
I b i d . . p .2 6 3 .
13.
I b i d ... p .2 5 2 .
14.
I b i d . . p . 256.
15.
N., I.:, F l g h e r and F . M. H am er, J,. Chem. S o c . , 1 9 3 0 .
2502.
-6 6 -
” 67"°
16.
j.
L a n d o l t - B t i r n s t e l n , Z a h le n w e rte und F v m k tlo n e n aus'
P h y s l k . O hem le. A s tro n o m le .' G-eophyisik und t e c h n l k .
I I . B and, 8 . T e l l . , . S p r l n g e r - V e r l a g ,, B e r l i n , 1 9 6 2 ,
p . 5 -6 1 0 .
•' .
17.
M u r r e ll., lo o , c i t . . p . 189.
18.
I b i d . . p .. 1 9 0 , 1 9 3 .
19.
‘ I b i d . . p . 19.0, 206.
,
20.
E. L i p p e r t , W. .N fig e le , I . . S e i b o l d - B l a n k e n s t e i n ,
U. S t a i g e r and. W.. V o ss, Z. Anal... Chem.,, 1 7 0 ,..I ( 1 9 5 9 ).
21.
R. J . A rg a u e r and. C. E . W h ite , ,A nal. C hem ., 2 6 ; .
368 :(19,64). '
!
•
’
‘
.
.
.
22.
R. J . A rg a u e r,, S p e c t r a C h a r a c t e r i s t i c s o f F l u o r e s c e n t
C h e l a t e s . P h . D .. T h e s is ,,.,U n i v e r s i t y o f M a ry la n d , ',.
. J u n e 1 9 6 3 , P P . 1 2 -4 2 .
23.
I n t e r n a t i o n a l C r i t i c a l . S a b l e s o f N u m e ric a l D a ta .
P h y s i c s . . C h e m is try and T e c h n o lo g y ^ Mo O ra w -H ill
■Book G o .,.. I n c . , New Y o rk , .1930,... V o l. 7 ,; p . 1 3 .
24.
I b i d ... p . 3 4 .
25.
W.'-H. M e lh u is h , ' J . P h y s . Chem1 ,
26.
0 . W eber and F . W. J . T e a le ,. T r a n s . F a ra d a y S o c . ,
5 2 , 646 ( 1 9 5 7 ) ,
27%
P a r k e r . I o c , c i t . . p’. 1 7 0 .
28.
A. C. C r a ig , P r i v a t e C o m m u n icatio n . .
29.
W. W est and S., P e a r c e , J . P hys.. Chem. , 69,.. 1894
(1 9 6 5 ).
30.
S. Y oung, J ;. Chem. . S o c . , 7 5 , .1 7 2 (18 9 9 ) a n d A. F.
S h e p a rd and A. L , Henne1, I n d . 'E n g . C hem ., 22,
356
31.
(
1930 ) . .
.
'
229 ( 1 9 6 1 ) ,
.
C,. A. P a r k e r and W, T. R e e s , -A n a ly s t, 85.,. 587 ( i 9 6 0 ) .
-
3 2 .,
68 -
W. I . F i s h e r and F . M. H am er, «T. . Chem. S o o ,.. 1 9 3 4 .
962.
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