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-NH2py) [Co(PhN2O2)2(2-NH2py)2] (1), [Ni(PhN2O2)2(2-NH2py)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 pseudo-hexagonal-grid sheets. In each crystal structure the two-dimensional supramolecular networks are controlled by both hydrogen bonds and π...π stacking interactions.