Electrochemical and EPR investigation on bis-toluene Cr(I) complexes. [Cr(n6-CH3C6H5)2][dbcp-NO2] ([dbcp NO2] = 1,2-dibenzoyl-4-nitrocyclopentadienyl anion): the first example of a [Cr(n6-CH3C6H5)2] cation containing a cis -eclipsed arrangement of toluene

The reaction of Cr(g6-CH3C6H5)2 with dbcpH-NO2 (dbcpH-NO2 = 1-benzoyl-3-nitro-6-hydroxy-6-phenyl fulvene) proceeds with the evolution of dihydrogen and formation of the ionic derivative [Cr(n6-CH3C6H5)2][dbcp-NO2] (dbcp-NO2 = 1,2-dibenzoyl-4-nitro-cyclopentadienyl anion) which was characterizedby X-ray diffraction, electrochemical and EPR techniques. The cation [Cr(n6-CH3C6H5)2]+, which in the solid state presents an unprecedented cis-eclipsed arrangement of the arene rings, undergoes a chemically reversible, one-electron reduction to the corresponding neutral derivative.