X-ray structure and density functional theory studies of an unexpected product: trans-bis{2-[(2-cyanoethyl)iminomethyl]phenolato}copper(II)

The title compound, [Cu(C10H9N2O)(2)] or [Cu-II(CYMB)(2)], (I), was obtained in an attempt to reduce trans-bis(2-{[3,5-bis-(trifluoromethyl) phenyl] iminomethyl} phenolato) copper(II), [Cu(TIMB)(2)], (II), with bis(pentamethylcyclopentadienyl)-cobalt(II) [decamethylcobaltocene, Cp*Co-2, (III)]. The molecular structure of (I) has the Cu-II centre located on an inversion centre of the C2/c space group. A density functional theory (DFT) analysis at the B3LYP/Lanl2dz(CuF); 6-31G**(CHNO) level performed in order to optimize the structures of the free ligands CYMB- and TIMB-, and the metal complexes [Cu-I/II(CYMB)(2)](-/0) and [Cu-I/II(TIMB)(2)](-/0), reproduced well the X-ray diffraction structure and allowed us to infer the insertion of the cyanomethide anion on the 3,5-bis(trifluoromethyl) phenyl system from an evaluation of the Mulliken atomic charges and the electronic energies.