Controlling Conformations in Alternating Dialkylsilylene-Spaced Donor-Acceptor Copolymers by a Cooperative Thorpe-Ingold Effect and Polymer Folding
作者:Chih-Hsien Chen、Yen-Chin Huang、Wei-Chih Liao、Tsong-Shin Lim、Kuan-Lin Liu、I-Chia Chen、Tien-Yau Luh
DOI:10.1002/chem.201102032
日期:2012.1.2
effect on the local conformation around the silicon atom. The differences in the small energetic barriers for each of the conformational states may be amplified by extending the distance of the folding structure, which results in perturbing the conformation of the polymers. These results suggest that the electronic interactions between adjacent donor–acceptor pairs in these copolymers are controlled by
已经设计了一系列二烷基甲硅烷基间隔的共聚物6和7,它们分别包含Me 2 Si和i Pr 2 Si间隔基,并且具有交替的供体和受体生色团,并通过氢化硅烷化进行区域选择性合成。每个重复单元的供体和受体生色团之比为2:1,两个供体生色团通过三亚甲基桥连接。使用4-氨基苯乙烯部分作为供体,并使用一系列具有不同还原电位的受体发色团。两个稳态和动力学测量揭示,在光诱导电子转移(PET)6遵循Marcus理论,其中观察到正常区域和反向区域。另一方面,i Pr 2 Si间隔共聚物7仅由于供体和受体生色团之间的基态相互作用而显示出电荷转移配合物的吸收和发射。光物理行为的差异可能是由相邻的供体和受体发色团之间的距离差异引起的。硅原子上取代基的体积(即Me与iPr)可能会对硅原子周围的局部构象产生Thorpe-Ingold效应。可以通过延长折叠结构的距离来扩大每个构象态的小能量屏障的差异,这会扰乱聚合物的构象。