新型香豆素酮类不对称双光子染料的合成及其光物理性质

本文以二苯乙烯和香豆素为共轭桥,二乙氨基为电子给体,羰基为电子受体,合成了一个具有D-π1-A-π2-D结构的香豆素酮类双光子染料C3.用紫外-可见光谱、荧光光谱研究了该化合物的光物理性质.发现在光作用下C3很容易发生分子内电荷转移,进而转变为扭曲的分子内电荷转移,产生很大的偶极矩变化.以飞秒脉冲激光为激发光源,用上转换荧光法测定了其双光子吸收截面.在激发波长为850 nm时,新化合物的双光子吸收截面值达1292 GM,比同系列香豆素酮衍生物C1、C2的双光子吸收截面值高一到两个数量级.

Synthesis and Photophysical Characteristics of a Novel Two-photon Absorption Unsymmetrical Ketocoumarin

A novel ketocoumarin derivative C3 presented a Dπ_1-A-π_2-D structure with diethylamino as the electron donor(D),carbonyl as the electron acceptor(A),coumarin and stilbene as the conjugating bridge was synthesized.Its photophysical characteristics were studied using UV-Vis and fluorescence spectra.The result showed that upon excitation compound C3 could form its intramolecular charge transfer state easily and furthermore transform to a twisted intramolecular charge transfer state accompanying with a very large change of dipole moment.The two-photon absorption cross-section of the new compound was measured by the up-converted fluorescence method with femtosecond laser pulses.It was obtained as 1292 GM at 850 nm,which is one to two orders of magnitudes larger than those of the reference compounds C1 and C2.