Control of the coordination mode of NO 2 − by the nature of the amine ligand: the importance of H-bond. Crystal structures of the [ mer-Ni(dpt)(NO 2) 2] ( I) and [ trans-Ni(333-tet)(NO 2) 2] ( II)

Abstract

Two new nickel(II) amine nitrite compounds were obtained and crystal structures were determined. The compound [ mer-Ni(dpt)(NO 2) 2] ( I), which crystallizes in the monoclinic system space group P2 1/ a, is a polymer and there is only one nickel moiety within an asymmetric unit. Each nickel atom is in an octahedral coordination environment and coordinated by three nitrogens of the amine ligand, one nitrogen of nitro(N) group, one nitrogen of a μ-nitro(N,O), and one oxygen of a μ-nitro(N,O) group. The mononuclear compound [Ni(333-tet)NO 2) 2] ( II) crystallizes in space group P 1 ̄ . Compound II is neutral, mononuclear, with two nitrite ligands bonded to the central nickel atom through their nitrogens, and located in positions trans to each other. The factors affecting the nitrite coordination mode are discussed. Intra- and/or inter-molecular hydrogen bonds are proposed to be one of the important factors in determining bonding modes and selection of crystallization pathways.