Y. Kang, S. Wang / Tetrahedron Letters 43 (2002) 3711–3713
Table 1. Photophysical data for selected compoundsa
3713
Compound
Absorption (umax, nm)
Emission (umax, nm)
Decay lifetimeb (t, ms)
Quantumc yield (Fem
)
5
6
7
8
9
10
324
332
344
356
360
362
361
382
386
405
416
430
3.7
3.6
4.8
5.1
28.5
29.3
0.69
0.76
0.79
0.31
0.65
0.73
a All data were collected in dichloromethane solution at room temperature (concentration: [M]=6.7×10−5 M).
b The decay profiles of all the compounds were composed of two or three exponential functions. However, we present the longest lifetime of each
compounds for clarity.
c The quantum yields were obtained by comparing to 9,10-diphenylanthracene (0.9) as a reference.
3933; (c) Wang, S. Coord. Chem. Rev. 2001, 215, 79 and
references cited therein; (d) Gornitzka, H.; Stalke, D.
Eur. J. Inorg. Chem. 1998, 311.
2. (a) Skotheim, T.; Reynold, J.; Elsenbaumer, R. Handbook
of Conducting Polymers; Marcel Dekker: New York,
1998; (b) The Chemistry of the CarbonꢀCarbon Triple
Bond; Patai, S.; Ed.; Wiley & Sons: New York, 1978; (c)
Yamaguchi, S.; Shirasaka, T.; Tamao, K. Org. Lett.
2000, 2, 4129; (d) Matsumi, N.; Naka, K.; Chujo, Y. J.
Am. Chem. Soc. 1998, 120, 5112; (e) Kayser, B.; Altman,
J.; Beck, W. Tetrahedron 1997, 53, 2475.
Figure 1. UV–vis absorption and fluorescent emission spectra
of 10 in dichloromethane at room temperature.
3. (a) Kantzidis, M. G. Chem. Eng. News 1990, 36; (b)
Roncali, J. Chem. Rev. 1992, 92, 711.
4. (a) Prasad, N. P.; Williams, D. J. Introduction to Nonlin-
ear Optical Effects in Molecules and Polymers; John
Wiley: New York, 1991; Chapter 10; (b) Nalwa, H. S.
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extended conjugation in compounds 9 and 10 may also
be responsible for the enhanced photoluminescent
efficiencies for 9 and 10, compared to that of 8. Com-
pounds 5–10 also display intense phosphorescent emis-
sion in the solid state or in solution at low temperature.
The details of phosphorescence displayed by these com-
pounds are currently being investigated.
In conclusion, we have achieved the syntheses of a new
class of highly efficient blue emitters with rigid-rod
structures. From our preliminary investigations of 5–
10, some of these new compounds have a high thermal
stability and a high glass transition temperature. Fur-
ther investigation on thermal behavior, electrochem-
istry, electroluminescent properties and coordination
chemistry of these new molecules is in progress.
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670; (b) Lindley, J. Tetrahedron 1984, 40, 1433; (c) Fanta,
P. E. Synthesis 1974, 1.
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