Photophysics of arylene and heteroaryleneethinylenes

被引:47
作者
Birckner, E
Grummt, UW [1 ]
Göller, AH
Pautzsch, T
Egbe, DAM
Al-Higari, M
Klemm, E
机构
[1] Univ Jena, Inst Phys Chem, D-6900 Jena, Germany
[2] Univ Jena, Inst Organ & Makromol Chem, D-6900 Jena, Germany
关键词
D O I
10.1021/jp010546n
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The absorption spectra and the stationary and time-resolved emissions of a series of the title compounds are investigated. Various combinations of ethinylene, p-phenylene, biphenyl-4,4 ' -diyl, fluorenyl-2,7-diyl, 3- or 4-pyridyl, phenanthroline-3,8-diyl, 2,2 '- bipyridine-5,5 ' -diyl, and 2,2 '- bipyridine-4,4 ' -diyl molecular units allow a systematic structure variation, e.g., size of pi system, type of aza-substitution, linear or angular chains. Most compounds are highly fluorescent. Radiationless deactivation via internal conversion and to a lesser extend intersystem crossing become efficient if forbidden states exist close to the strongly allowed pi pi* states (proximity effect) which can be traced back to a smaller size of the pi system or reduced conjugation due to meta-linkages of heteroaromatic rings. Aza-substitution may change the deactivation behavior but it does insignificantly influence the absorption and fluorescence spectra. Replacing phenanthrene for 2,2 ' -bipyridine in the larger compounds does not alter the spectroscopic and the deactivation behaviors.
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页码:10307 / 10315
页数:9
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