Thanikachalam V, Jayabharathi J, Arunpandiyan A, Ramanathan P
Department of Chemistry, Annamalai University, Annamalainagar, 608 002, Tamilnadu, India.
J Fluoresc. 2014 Mar;24(2):377-87. doi: 10.1007/s10895-013-1302-y. Epub 2013 Oct 6.
This article presents a facile synthesis of novel class of bluish-green fluorescent 2-((E)-2-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)vinyl)phenol [PPIVP] and their optical, electrochemical and thermal properties. Detailed photophysical and quantum chemical studies have been performed to elucidate the origin of the dual emission shifts. PPIVP undergo excited state intramolecular proton transfer (ESIPT) reaction leading a large Stoke's shifted fluorescence emission from the phototautomer. The results of quantum chemical investigations not only confirmed the intramolecular charge transfer characteristics of the ESIPT tautomers but also provided a rational for the observed high fluorescence quantum efficiency in the solid state. The high photoluminescence quantum yield in the solid state is ascribed to twisted chromophores due to phenyl substituents at 1,2-position of the phenanthroimidazole ring which restricted intramolecular motion, leading to an optically allowed lowest optical transition without self quenching.
本文介绍了一种新型蓝绿色荧光2-((E)-2-(1-苯基-1H-菲并[9,10-d]咪唑-2-基)乙烯基)苯酚[PPIVP]的简便合成方法及其光学、电化学和热性能。已进行了详细的光物理和量子化学研究，以阐明双发射位移的起源。PPIVP发生激发态分子内质子转移(ESIPT)反应，导致光互变异构体产生大斯托克斯位移荧光发射。量子化学研究结果不仅证实了ESIPT互变异构体的分子内电荷转移特性，还为固态下观察到的高荧光量子效率提供了合理依据。固态下高光致发光量子产率归因于菲并咪唑环1,2位的苯基取代基导致发色团扭曲，限制了分子内运动，从而产生了无自猝灭的光学允许的最低光学跃迁。
