Dinitro and Quinodimethane Derivatives of Terthiophene That Can Be Both Oxidized and Reduced. Crystal Structures, Spectra, and a Method for Analyzing Quinoid Contributions to Structure
作者:Ted M. Pappenfus、Jonathan D. Raff、Eric J. Hukkanen、Jason R. Burney、Juan Casado、Steven M. Drew、Larry L. Miller、Kent R. Mann
DOI:10.1021/jo025572b
日期:2002.8.1
anion radical and dianion. The spectra of 2 and its three redox partners were analyzed in terms of a limiting structure in which the neutral 2 has orbitals corresponding to those of a substituted-terthiophene dication. Compound 1 crystallizes with the thiophene rings held in an unusual nonplanar, cisoid configuration in face-to-face pi-stacks, with a spacing between molecules of 3.65 A. The C-C bond lengths
两个新的低聚噻吩,二硝基化合物3',4'-二丁基-5,5''-二硝基-2,2':5',2'-对噻吩(1)和喹二甲烷3',4'-二丁基- 5,5''-双(二氰基亚甲基)-5,5''-二氢-2,2':5',2''-对噻吩(2)已通过电化学,UV-vis-NIR-合成红外光谱,ESR和X射线晶体学。这些被设计为电子和空穴载流子的化合物具有氧化还原特性,这对于低聚噻吩是不寻常的。循环伏安法和光谱电化学表明,每种化合物均可被氧化成阳离子自由基,并被还原成阴离子自由基和二价阴离子。根据限制结构分析了2及其三个氧化还原配偶体的光谱,其中中性2的轨道对应于取代的对噻吩指示的轨道。化合物1结晶时,噻吩环在面对面的pi堆栈中以不寻常的非平面,类cisoid构型保持,分子之间的间距为3.65A。硝基取代的外环的CC键长具有quinoid特性。化合物2与噻吩环一起以平面,Transoid构型结晶。分子被固定在由p