© The Royal Society of Chemistry 2000
Supplementary Data
A dibenzo-16-crown-5 fluoroionophore for selective emission ratio sensing of Na+ in
basic aqueous dioxane solution
Takashi Hayashita,*a Shinichiro Taniguchi,a Yoshihiko Tanamura,a Tatsuya
Uchida,a Seiichi Nishizawa,a Norio Teramae,*a Yong Suk Jin, b Jong Chan Lee,b and
Richard A. Bartschc
a
Department of Chemistry, Graduate School of Science, Tohoku University, Aoba-ku,
Sendai 980-8578, Japan
b
c
Department of Chemistry, Chung-Ang University, Seoul 156-756, Korea
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas
79409-1061, USA
© The Royal Society of Chemistry 2000
Determination of binding constant:
The 1:1 binding constant of 1 for Na+ is calculated from a Benesi-Hildebrand
plot analysis.a On the assumption that the fluorescence change is only induced by the
formation of a 1:1 complex between 1 (L) and metal ion (M), the fluorescence intensity
(I) can be expressed by the following equations:
I = L[L] + ML[ML]
(A-1)
[Lt] = [L] + [ML]
(A-2)
[ML]
K=
(A-3)
[M][L]
where L and ML are the fluorescence quantum yields for 1, and  denotes the
instrumental constant including the excitation light intensity and the molar absorptivity of
1. From these equations, the Benesi-Hildebrand type equation (A-4) can be derived as,
1
I
=
1
+
bDfK[L t][ M]
1
bDf[L t]
DI = I - I 0, Df = f ML - f L
(A-4)
(A-5)
The double-reciprocal plots of fluorescence intensity recorded at 387 nm and
459 nm as a function of Na+ concentration according to equation (A-4) are shown in Fig.
A. All plots show linear relationship with correlation coefficients of higher than 0.995,
and the 1:1 binding constant is obtained from the following equation,
K = (y-intercept)/(slope)
(A-6)
We have repeated this experiment twice under the same experimental condition,
and obtained the average binding constant value of 21917 (M-1).
Reference (a) K. A. Connors, Binding Constants; Wiley, New York, 1987, pp. 147-187.
© The Royal Society of Chemistry 2000
-1 -1
R = 0.997
K = 202 M -1
-2
1/
D
Iat 387 nm
-2
(a) 387 nm
-3 -3
-4 -4
50
0
100
200
300
400
(b) 459 nm
40
R = 0.996
K = 205 M -1
1/
D
Iat 459 nm
40
30 30
20 20
0
10 10
0
100
100
200
200
300
300
400
400
[Na +]-1 / M-1
Fig. A Benes i-Hildebrand plots at (a) 387 nm and (b) 459
nm. In 4:1 1,4-dioxane-water (v/v), [ 1] = 8.0x10
[TMAOH] = 33 mM. ex = 355 nm.
-7
M,