Cobalt(II) and nickel(II) complexes of quinoline-2-carboxylate

The title complexes, trans-diaquabis(quinoline-2-carboxylato-kappa(2)N,O) cobalt(II)-water-methanol (1/2/2), [Co(C10H6NO2)(2)-(H2O)(2)].2CH(4)O.2H(2)O, and trans-diaquabis( quinoline-2-carboxylato-kappa(2)N,O) nickel(II)-water-methanol (1/2/2), [Ni(C10H6NO2)(2)(H2O)(2)].2CH(4)O.2H(2)O, are isomorphous and contain Co-II and Ni-II ions at centers of inversion. Both complexes have the same distorted octahedral coordination geometry, and each metal ion is coordinated by two quinoline N atoms, two carboxylate O atoms and two water O atoms. The quinoline-2-carboxylate ligands lie in trans positions with respect to one another, forming the equatorial plane, with the two water ligands occupying the axial positions. The complex molecules are linked together by hydrogen bonding involving a series of ring patterns which include the uncoordinated water and methanol molecules.