Formation of Singly Bonded PhCH2C60–C60CH2Ph Dimers from 1,2-(PhCH2)HC60 via Electroreductive C60–H Activation

Singly bonded PhCH2C60–C60CH2Ph dimers are generated via controlled-potential bulk electroreduction and electrooxidation of 1,2-(PhCH2)HC60. The reaction mixture was purified by HPLC, and the isolated fraction was characterized with single-crystal X-ray diffractions, 1H and 13NMR, MS, elemental analysis, and cyclic voltammetry. It was shown that the fraction consists of two HPLC-inseparable PhCH2C60–C60CH2Ph regioisomers, which are assigned as the meso and racemic regioisomers. The bulk electrolysis processes for the formation of the dimers were followed by in situ cyclic voltammetry and were further corroborated with an in situ voltammetric titration of 1,2-(PhCH2)HC60 with tetra-n-butylammonium hydroxide (TBAOH), on the basis of which a reaction mechanism is proposed.