Cobalt(II), nickel(II) and copper(II) complexes of isoquinoline-3-carboxylate.

The crystal structures of the title complexes, namely trans-bis(isoquinoline-3-carboxylato-kappa2N,O)bis(methanol-kappaO)cobalt(II), [Co(C10H6NO2)2(CH3OH)2], and the corresponding nickel(II) and copper(II) complexes, [Ni(C10H6NO2)2(CH3OH)2] and [Cu(C10H6NO2)2(CH3OH)2], are isomorphous and contain metal ions at centres of inversion. The three compounds have the same distorted octahedral coordination geometry, and each metal ion is bonded by two quinoline N atoms, two carboxylate O atoms and two methanol O atoms. Two isoquinoline-3-carboxylate ligands lie in trans positions, forming the equatorial plane, and the two methanol ligands occupy the axial positions. The complex molecules are linked together by O-H...O hydrogen bonds between the methanol ligands and neighbouring carboxylate groups.