二面角
指示
化学
自由基离子
小提琴手
结晶学
电子顺磁共振
Crystal(编程语言)
光化学
计算化学
分子物理学
核磁共振
分子
氢键
离子
物理
有机化学
程序设计语言
计算机科学
作者
Andrew C. Benniston,Anthony Harriman,Peiyi Li,James P. Rostron,Ross W. Harrington,William Clegg
标识
DOI:10.1002/chem.200700872
摘要
Abstract A small series of N , N ′‐dimethyl‐4,4′‐bipyridinium dication derivatives (commonly known as viologens) has been synthesized and fully characterized; a short dialkoxy tether attached at the 3,3′‐positions is used to alter the central dihedral angle. These angles were determined by both single‐crystal X‐ray diffraction and by computational studies made for the dication, radical cation, and neutral species in a solvent reservoir. The dihedral angle derived for the dication controls the first reduction potential, whereas the geometry of the resultant π‐radical cation determines the magnitude of the second reduction potential. The optical absorption spectra recorded for the various species, and especially those of the radical cations, and the EPR spectral parameters of the π‐radical cations also depend on the molecular geometry. In particular, the central dihedral angle influences the spin density distribution around the aromatic nucleus and, by way of comparison to the parent viologen, it has been possible to resolve the angle dependence from the inherent inductive effect of the strap. These results are considered in terms of the degree of electronic communication between the two aromatic rings, as controlled by the length of the tether.
科研通智能强力驱动
Strongly Powered by AbleSci AI