Cobalt(III) alkyl complexes of 1,2-bis(2-pyridinecarboxamido)benzene (H2bpb) and 4,5-dichloro-1,2-bis(2-pyridinecarboxamido)benzene (H2bpc) and X-ray crystal structures of [Co(bpc)(CH2CH2CMe=CH2)(H2O)] and [Co(bpb)Et(H2O)]

Abstract

A series of organo and non-organo cobalt complexes of bpb and bpc ligands [H2bpb = 1,2-bis(2-pyridinecarboxamido)benzene, H2bpc = 4,5-dichloro-1,2-bis(2-pyridinecarboxamido)benzene] have been synthesised. Complexes prepared include Na[CoL(CN)2], Na[CoL(N3)2], [CoL(py)2]ClO4 and [CoL(R)(H2O)] (L = bpb or bpc; py = pyridine; R = Me, Et, Pri or CH2CH2CMe=CH2). The complex [CoL(CH2CH2CMe=CH2)(H2O)] was formed as a rearrangement product from the reaction of 3,3-dimethylallyl bromide and [CoL]·H2O in the presence of NaBH4 and NaOH in methanol. The complexes [Co(bpc)(CH2CH2CMe=CH2)(H2O)] 1 and [Co(bpb)Et(H2O)] 2 have been characterized by X-ray crystallography: 1, space group Pnma, a = 13.934(2), b = 12.204(2), c = 13.173(2) Å, Z = 4, and R = 0.046 for 1129 observed reflections; 2, space group Pnma, a = 15.072(1), b = 12.119(2), c = 9.884(3) Å, Z = 4, and R = 0.034 for 1387 observed reflections. Electrochemical studies on the one-electron oxidation of these complexes suggest the involvement of the equatorial ligand in these processes.