Preparation and Characterization of Cobalt(III) Complexes Containing 1,1′-Bis(diphenylphosphino)ferrocene (dppf) or 1,1′-Bis(dimethylphosphino)ferrocene (dmpf) as a Bidentate Ligand, and Molecular Structures of [Co(acac)2(dmpf)]B(C6H5)4 and [Co(dtc)2(dmpf)]B(C6H5)4 (acac = 2,4-pentanedionate ion, dtc = dimethyldithiocarbamate ion)

Four new complexes, [Co(acac or dtc)2(dppf or dmpf)]X (X = BF4, B(C6H5)4) have been prepared and characterized by absorption and 1H NMR spectra, and electrochemical measurements. The [Co(acac)2(dppf)]+ complex exhibits the first d-d band at much lower energy than that of [Co(acac)2(dppe)]+ (dppe = 1,2-bis(diphenylphosphino)ethane), while the other complexes give the bands at similar energies to those of the corresponding diphosphine complexes. The structures of two dmpf complexes have been determined by the X-ray diffraction method. Crystal data are: [Co(acac)2(dmpf)]B(C6H5)4 (1), monoclinic, P21/a, a = 20.366(4), b = 13.513(2), c = 16.860(2) A, β = 108.09(2)°, V = 4411(1) A3, Z = 4, R = 0.041 for 5774 reflections. [Co(dtc)2(dmpf)]B(C6H5)4 (2), monoclinic, C2/c, a = 33.573(7), b = 10.148(1), c = 31.039(6) A, β = 123.13(1)°, V = 8856(2) A3, Z = 8, R = 0.044 for 6323 reflections. In these complexes dmpf functions as a bidentate chelate ligand with the Co–P bond distances of 2.250(1)–2.257(2) A and the P–Co–...