The rates of degenerate electron exchange (electron self-exchange) of various cyanobenzenes have been measured by EPR line broadening technique in nine different solvents at room temperature. The molecules studied comprise besides benzene-1,2-dicarbonitrile, benzene-1,4-dicarbonitrile and benzene-1,2,4,5-tetracarbonitrile, the two isomeric tricyanobenzenes, benzene-1,2,3-tricarbonitrile and benzene-1,2,4-tricarbonitrile, the anion radicals of which have not been characterized before.
The experimentally observed rates vary from 4.5 × 108 to 44.0 × 108 M−1 s−1 and show the pronounced dependence on the longitudinal relaxation times, τL, of the solvents. The solvent dynamical effect so manifested is confirmed with remarkable clarity using solvents spanning a wide range of τL-values, which comprise acetonitrile (0.2 ps) and
采用EPR线宽技术在九种不同溶剂中测量了各种氰基苯的退化电子交换率(电子自交换),温度为室温。所研究的分子除了苯-1,2-二羧腈、苯-1,4-二羧腈和苯-1,2,4,5-四羧腈之外,还包括两种同分异构体三氰基苯,苯-1,2,3-三羧腈和苯-1,2,4-三羧腈,其阴离子自由基以前未被表征。
实验观察到的速率从4.5×108到44.0×108 M−1 s−1 不等,并且显示出对溶剂的纵向弛豫时间τL的显著依赖性。所表现的溶剂动力学效应在使用跨越广泛的τL值的溶剂时得到了明显的确认,这些溶剂包括乙腈(0.2 ps)和