Hydrogen-bonded hexagonal and pseudo-hexagonal grid motifs in supramolecular cobalt(II) and nickel(II) cupferronato complexes incorporating neutral N-donors with intermolecular NH2 connectors and solvent molecules

The cobalt(II) and nickel(II) cupferronato (N-nitroso-N-phenylhydroxylaminato) mixed-ligand complexes of 2-aminopyridine (2-NH(2)py) [Co(PhN2O2)(2)((2)-NH(2)py)(2)] (1), [Ni(PhN2O2)(2)(2-NH(2)py)(2)] (2) and 2,6-diamino-4-phenyl-1,3,5-triazine (dpt) [Co(PhN2O2)(2) (dpt)(2)]. [Co(PhN2O2)(2) (EtOH)(2)] (3) have been synthesized and characterized by X-ray diffraction analysis. The cobalt (1) and nickel (2) complexes are isostructural. The crystal lattice of (3) contains different neutral cobalt(II) complexes [Co(PhN2O2)(2) (dpt)2] (3a) and [Co(PhN2O2)(2)(EtOH)(2)] (3b). Molecules of (1)-(3) contain octahedral metal centres with all-cis-(1) and -(2) and all-trans-(3) disposal of the ligands. Intramolecular N-H . . .O hydrogen bonding between the NH2 groups and the O atom of the cupferronato anion can be observed in (1)-(3). Intermolecular N-H . . .O and N-H . . .N interactions between symmetry-related molecules of (1) and (2) led to hexameric aggregates which connect through common edges into a two-dimensional supramolecular network of hexagonal-grid type. In complex (3) the self-complementary dpt units of the (3a) molecules are maintained by intermolecular N-H . . .N hydrogen bonds, generating infinite chains. These (3a) chains are crosslinked by the (3b) subunits via N-H . . .O and O-H . . .N hydrogen bonds, thus completing the parallel two-dimensional supramolecular network consisting of pseudohexagonal-grid sheets. In each crystal structure the two-dimensional supramolecular networks are controlled by both hydrogen bonds and pi . . . pi stacking interactions.