# Supplementary Material (ESI) for Chemical Communications
# This journal is © The Royal Society of Chemistry 2003
Supplementary Information
Thermally Reversible Fluorescent Polymorphs of Alkoxy-CyanoSubstituted Diphenylbutadienes: Role of Crystal Packing in Solid
State Fluorescence
Riju Davis,a Nigam P. Rathb and Suresh Das*a
a
Photosciences and Photonics Division, Regional Research Laboratory (CSIR)
Trivandrum – 695 019, INDIA.
b
Department of Chemistry, University of Missourie-St. Louis, St. Louis, MO 63121, USA.
I
Experimental Section
Solid state emission spectra were recorded on a SPEX Fluorolog
spectrometer. Diffuse reflectance spectra were recorded using a Shimadzu
integrating sphere assembly attached to a Shimadzu UV-Vis-NIR 3101 PC
spectrophotometer. BaSO4 was used as the reflectance standard. Temperature of
the samples was controlled using a Linkam THMS 600 heating and freezing stage
connected to a Linkam TP92 temperature programmer. Powder XRD patterns
were recorded on a Rigaku Miniflex diffractometer using Cu-K radiation ( =
1.540 Å) with Ni-filter. Single crystal XRD analyses were carried out on a
Siemens SMART-1K CCD diffractometer with Mo source and graphite
monochromator.
Fluorescence lifetimes were determined using an Edinburgh Instrument
FL900CD single photon counting system and the data were analyzed by
Edinburgh software. The fluorescence decay profiles were analyzed using
biexponential least square fitting. The goodness of the fit was judged by the
reduced 2 values (1.33 in all cases).
2
II
Table 1. Absorption and
diphenylbutadiene derivatives
Compound
data
for
solid
films
of
the
Flu. Lifetime data
Abs.max
(nm)
Flu.max
(nm)
BC1
375, 440
460, 505
1.12
(91.2)
4.30
(8.8)
1.10
BC4
370, 450
465, 495
2.38
(12.4)
5.41
(87.6)
1.02
BC8
365, 430
460
1.17
(89.2)
3.64
(10.8)
1.33
385
450, 480
1.38
(79.3)
3.12
(20.7)
0.93
BC12
a
fluorescence
a
1(ns)
(bF1%)
a
2(ns)
(bF2%)
c2
= lifetime; bF% = fractional contribution c2 = fitting parameter
III
4.0 Å
Counts (a. u.)
1
4.0 Å
19.7 Å 9.7 Å
5
10
15
2
20
25
30
Figure 1. The powder XRD patterns of stable (blue fluorescent) polymorph of
BC8.
3
IV
Counts (a. u.)
1 24.3 Å
8.0 Å
4.0 Å
12.0 Å
3.9 Å
0
5
10
15
20
25
30
2
Figure 2. The powder XRD patterns of metastable (green fluorescent) polymorph
of BC8.
V
3.5
7.7 Å
Counts (a. u.)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
15.1 Å
5
10
15
2
20
25
Figure 3. The powder XRD patterns of BC1.
30
4
VI
10.1 Å
3.0
Counts (a. u.)
2.5
2.0
1.5
1.0
20.8 Å
0.5
6.7 Å
0.0
5
10
15
20
25
30
2
Figure 4. The powder XRD patterns of BC4.
VII
4.3 Å
Counts (a. u.)
4
3
2
3.7 Å
1
0
5
10
15
20
25
2
Figure 5. The powder XRD patterns of BC12.
30