Donor-substituted distyrylpyrazines: influence of steric congestion on UV-Vis absorption and fluorescence
作者:Christoph Wink、Heiner Detert
DOI:10.1002/poc.2978
日期:2013.2
Di(p‐aminostyryl)pyrazines with voluminous substituents on the nitrogen and in the adjacent positions were prepared via twofold aldol condensation. Absorption and emission spectra are influenced by increasing steric hindrance because the orbital overlap between nitrogen and π‐system is modulated by voluminous groups. Strong solvatochromism of the fluorescence and huge Stokes shifts result from amplified
通过两次醇醛缩合制备在氮上和相邻位置具有大量取代基的二(对氨基苯乙烯基)吡嗪。吸收和发射光谱受空间位阻增加的影响,因为氮和π系统之间的轨道交叠受到大量基团的调节。强烈的溶剂化变色现象和巨大的斯托克斯频移是由于激发态下供体-受体相互作用的放大所致。质子化首先发生在末端氨基,然后是中央吡嗪的质子化。随着酸强度的增加,吸收光谱和发射光谱首先会变为蓝色,然后再发生红移。版权所有©2012 John Wiley&Sons,Ltd.