Synthesis, Structure, and Nonlinear Optical Properties of Cross-Conjugated Perphenylatediso-Polydiacetylenes
作者:Yuming Zhao、Aaron D. Slepkov、Clement Osei Akoto、Robert McDonald、Frank A. Hegmann、Rik R. Tykwinski
DOI:10.1002/chem.200400822
日期:2005.1
Monodisperse, cross-conjugated perphenylated iso-polydiacetylene (iso-PDA) oligomers, ranging from monomer 15 to pentadecamer 25, have been synthesized by using a palladium-catalyzed cross-coupling protocol. Structural characteristics elucidated by X-ray crystallographic analysis demonstrate a non-planar backbone conformation for the oligomers due to the steric interactions between alkylidene phenyl
已经通过使用钯催化的交叉偶联方案合成了单分散的,交叉共轭的全苯基化的异聚二乙炔(iso-PDA)低聚物,其范围从单体15到十五酮25。X射线晶体学分析所阐明的结构特征表明,由于亚烷基苯基之间的空间相互作用,该低聚物具有非平面的骨架构象。低聚物的电子吸收光谱显示,随着链长从二聚体17b到十五碳二烯25的增加,最大吸收波长发生轻微的红移,这种趋势在九聚体22的阶段已达到饱和。荧光光谱证实了悬垂的苯基低聚物骨架上存在的基团增强发射,并且相对发射强度作为链长n的函数持续增加。该低聚物系列的分子三阶非线性度γ已通过差分光学克尔效应(DOKE)检测进行了测量,并显示出作为低聚物链长n的函数的超线性增加。分子建模和光谱研究表明,iso-PDA低聚物(n> 7)在溶液中采用螺旋状螺旋构象。