Behavior of the Heterogeneous Electron-Transfer Rate Constants of Arenes and Substituted Anthracenes in Room-Temperature Ionic Liquids

Abstract

We report the anodic oxidation of several arenes and anthracenes within room-temperature ionic liquids (RTILs). In particular, the heterogeneous electron-transfer rates (k 0 ) for substituted anthracenes and arenes are also investigated in l-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 2 mim][NTf 2 ]) and found not to obey the outer-sphere Marcus-type behavior of these compounds in contrast to the behavior in traditional organic solvents, in particular the predictions for k 0 with molecular size and solvent static dielectric constant. To obtain the electron-transfer rate for 9-phenylanthracene, the dimerization and heterogeneous electron-transfer kinetics of its electrogenerated radical cations is studied in [C 2 mim][NTf 2 ] and eight other RTILs and are both found to be largely independent of the solution viscosity.