Electrochemical and EPR investigation on bis-toluene Cr(I) complexes. [Cr(ƒØ6-CH3C6H5)2][dbcp-NO2] ([dbcp-NO2]ƒ{ = 1,2-dibenzoyl-4-nitrocyclopentadienyl anion): the first example of a [Cr(ƒØ6-CH3C6H5)2]ƒy cation containing a cis-eclipsed arrangement of toluene rings

The reaction of Cr(ƒØ6-CH3C6H5)2 with dbcpH−NO2 (dbcpH−NO2 = 1-benzoyl-3-nitro-6-hydroxy-6-phenyl fulvene) proceeds with evolution of dihydrogen and formation of the ionic derivative [Cr(ƒØ6-CH3C6H5)2][dbcp−NO2] (dbcp−NO2 = 1,2-dibenzoyl-4-nitro-cyclopentadienyl anion) which has been characterized by X-ray diffraction, electrochemical and EPR techniques. The cation [Cr(ƒØ6-CH3C6H5)2]+, which presents a unprecedented cis-eclipsed arrangement of the arene rings, undergoes a chemically reversible, one-electron reduction to the corresponding neutral derivative.