Crystal structure of [Co(bipy)(maleato) (H₂O)₃]·H₂O (bipy = 2,2′-bipyridine)

Preparation of the mononuclear cobalt(II) complex, [Co(bipy)(maleato) (H₂O)₃]·H₂O (1) where bipy = 2,2′-bipyridine, were accomplished by reaction of an aqueous solution containing sodium maleate and an ethanolic solution of Co(NO₃)₂·6H₂O and bipy. The crystal structure of complex (1) was determined by X-ray crystallography. The complex crystallizes in the monoclinic space group P2¹/n with a = 9.477(3), b = 7.660(2), c =23.526 (3) Å, β = 97.64(2)°, V = 1692.6(6) ų, and Z = 4. The structure consists of discrete mononuclear cobalt molecules. The cobalt atom is six-coordinate and presents a slightly distorted octahedral geometry, which consists of the two imine N atoms of bipy, a terminal carboxylate O atom from maleato ligand, and a water O atom in the basal plane with Co-N bond distances of 2.116(2) and 2.124(3) Å and Co-O distances of 2.075(2) and 2.088(2) Å, respectively. The relatively shorter Co-O distances are due to the trans effect of the bipy ligand. The octahedral coordination is completed the other two water molecules. The coordinate and the lattice water molecules were identified by TG study.