Electrochemical and Theoretical Investigation of Corannulene Reduction Processes

The voltammetric generation of corannulene anions was investigated over a large range of experimentalconditions comprising either “traditional” electrochemical solvents, such as dimethylformamide, acetonitrile,and tetrahydrofuran, or “unconventional” solvents, such as liquid ammonia, liquid methylamine, or liquiddimethylamine, and several different supporting electrolytes. Strong ion pairing effects were found to dominatethe electrochemical generation of corannulene higher anions, and through the suitable choice of the solvent/electrolyte system, we observed, for the first time, the reversible electrochemical generation of up to thetriply reduced corannulene. The standard potentials obtained experimentally compared rather well with thetheoretical values calculated by ab initio and density functional methods, in which solvation and ion pairingeffect were explicitly taken into account. In particular, the calculations considered the effect of the electrolytecation size on ion pairing in order to rationalize the occurrence of the third reduction within the experimentalpotential window.