Electrosynthesis and structural characterization of two (C6H5CH2)4C60 isomers

The structural, spectral, and electrochemical properties of two (C6H5CH2)(4)C-60 isomers are reported. One is designated as the 1,4;1,4-(C6H5CH2)(4)C-60 isomer and the other as the 1,4;1,2-isomer of (C6H5CH2)(4)C-60. The two isomers were isolated by HPLC from the products obtained by a reaction between [(C6H5CH2)(2)C-60](2-) and C6H5CH2Br. X-ray data show that the two (C6H5CH2)(4)C-60 isomers differ from one another by the position of only one benzyl group and that, in each compound, the four benzyl addends are in close proximity. Both (C6H5CH2)(4)C-60 isomers undergo three one-electron reductions in PhCN containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) and have E-1/2 values which are more negative than values for either C-60 or 1,4-(C6H5CH2)(2)C-60 The monoanions of 1,4;1,4- and 1,4;1,2-(C6H5CH2)(4)C-60 were electrogenerated by bulk controlled-potential electrolysis in PhCN containing 0.2 M TBAP and characterized as to their spectral properties in both the visible and near-infrared regions.