不同位置取代的三氰基乙烯基蒽的光谱行为的研究

A STUDY OF SPECTROSCOPIC BEHAVIOR OF ANTHRACENE SUBSTITUTED BY TRICYANOVINYL IN DIFFERENT POSITION

本文设计合成了两个典型的共轭的电子给体与电子受体（Ｄ－Ａ）化合物：２－三氰基乙烯基蒽（２－ＴＣＶＡ）与９－三氰基乙烯基蒽（９－ＴＣＶＡ），通过极性效应，温度效应对它们基态与激发态的光谱行为进行了表征。研究表明：这两个化合物均表现出显著的电荷转移（ＣＴ）吸收峰，分子受光激发后，９－ＴＣＶＡ只能在非极性溶剂中产生分子内电荷转移（ＩＣＴ）态荧光，而２－ＴＣＶＡ在极性与非极性溶剂中都能从ＩＣＴ态发光．另外，温度效应显示冻结态下，２－ＴＣＶＡ只发射ＩＣＴ态荧光，而９－ＴＣＶＡ既发射类蒽（ａｎｔｈｒａｃｅｎｅ－ｌｉｋｅ）荧光又发射ＩＣＴ态荧光，造成这一现象的主要原因可能是２－ＴＣＶＡ与９－ＴＣＶＡ分子平面性上的差异而引起分子内电荷转移相互作用不同所致。文中还利用了Ｂｉｌｏｔ－Ｋａｗｓｋｉ公式估算了化合物２－ＴＣＶＡ在激发态与基态时偶极矩的差值为１８．８Ｄ。

Two conjugating electron donor-acceptor(D-A)compounds, 2-tricyanovinyl anthracene(2-TCVA)and 9-tricyanovinyl anthracene(9-TCVA), were synthesized and their spectroscopic properties in a series of solvents with different polarity and at different temperature were studied.The results reveal that the structure of 2-TCVA is more planar than 9TCVA at their ground state and the charge transfer bands show up in their absorption spectra.Fluorescence emits from intramolecular charge transfer(ICT)state for 9-TCVA in nonpolar solvents,while for 2-TCVA in both polar and non-polar solvents. When the molecule was freezed,2-TCVA emits fluorescence from its ICT state,while 9-TCVA emits dual fluorescence from its local and ICT state,due to the structure of 2-TCVA is more planar than 9-TCVA. The dipole moment difference between excited state and ground state for 2-TC-VA was estimated as 18.8 D.