Curtis M David, Cao Jie, Kampf Jeff W
Department of Chemistry, and the Macromolecular Science and Engineering Program, The University of Michigan, Ann Arbor, Michigan, USA.
J Am Chem Soc. 2004 Apr 7;126(13):4318-28. doi: 10.1021/ja0397916.
The solid-state structures of a series of bithiazole and thiophene oligomers, as well as a series of substituted pentacenes, are rationalized in terms of "pitch and roll" inclinations from an "ideal" cofacial pi-stack. Pitch inclinations translate adjacent molecules relative to one another in the direction of the long molecular axis, whereas roll inclinations translate the molecules along the short molecular axis. Thus, moderately large pitch distortions preserve pi-pi interactions between adjacent molecules, whereas roll translations greater than 2.5 A essentially destroy pi-pi overlap between adjacent molecules. The familiar herringbone packing is characterized by large roll distortions. It is shown that thiophenes tend to exhibit large roll translations, whereas thiazoles have small roll but large pitch translations. Substituted pentacenes tend to have both moderate pitch and roll distances. The relationship of molecular packing to transport properties is discussed.
一系列联噻唑和噻吩低聚物以及一系列取代并五苯的固态结构，根据与“理想”共面π堆积的“倾斜和翻滚”倾向进行了合理化解释。倾斜倾向使相邻分子沿长分子轴方向相对移动，而翻滚倾向使分子沿短分子轴移动。因此，适度大的倾斜畸变保留了相邻分子之间的π-π相互作用，而大于2.5 Å的翻滚平移基本上破坏了相邻分子之间的π-π重叠。常见的人字形堆积的特征是大的翻滚畸变。结果表明，噻吩倾向于表现出大的翻滚平移，而噻唑的翻滚小但倾斜平移大。取代并五苯往往具有适度的倾斜和翻滚距离。讨论了分子堆积与传输性质的关系。
