含有雜環芳香族的高效率二次非線性光學活性分子的合成

Abstract

我們合成一系列含有雜環﹐而以推拉電子基共軛系統為主體﹐具有二次非線性光學活性的發色團﹐並且研究它們的二次非線性光學活性和熱穩定性。π-π*電荷轉移吸收峰的位置﹐不僅和發色團分子內雜環的本質有關﹐而且和雜環所在的位置也有關係﹐要將thiophene 放在靠近推電子基的一端﹐而將thiazole放在靠近拉電子基的一端﹐如此一來在π-π*電荷轉移時消耗最少能量﹐會有較大的二次非線性光學活性﹐此一理論曾經由理論計算的結果發表過﹐而我們所合成發色團的二次非線性光學活性﹐正在測試中﹐我們預測用雜環來取代苯環﹐將會造成二次非線性光學係數（β）的大幅增加﹐另外其熱穩定性也和具有二苯乙烯結構的發色團相若。

A series of second-order nonlinear optical chromophores containing push-pull substituted conjugated systems with heteroaromatic spacers have been synthesized and their spectroscopic properties and thermal stability has been studies. The position of the π-π* charge -transfer absorption bands depend not only on the nature but also on the location of the heteroaromatic ring. Among the systems considered, the lowest energy of the π-π* charge -transfer occurred for chromophores in which thiophene at the donor end and thiazole is at the acceptor end of the molecule, the results are consistent with theoretical calculation reported .The measurements of the second-order molecular nonlinearity of the chromophores are currently underway ,we expect the appropriate replacement of benzene-ring structures by heteroaromatic ring will result in significant enhancement in β.The thermal stability of the chromophores are comparable to the corresponding stibene structure.