Assembly structures of 1:2 nickel(II) complex of 5-methylimidazol-4-yl-methylidene-l-phenylalanine and 1:2 nickel(II) complex of its racemic ligand

1:2 Nickel(II) complexes of 5-methylimidazol-4-yl-methylidene-l-phenylalanine (H2Ll-phe) and its racemic ligand (H2Ldl-phe) were synthesized and the crystal structures of the resultant [Ni(HLl-phe)2]·MeOH·3H2O (1) and [Ni(HLdl-phe)2]·6H2O (2) complexes were determined. Complex 1 crystallized in an acentrosymmetric monoclinic space group, P21 (No. 4). The nickel(II) ion is coordinated by (N2O)2 donor atoms from two tridentate H2Ll-phe ligands and has an octahedral coordination environment. In the crystal, 1 contains only the l-isomer and forms a homochiral 2D structure through hydrogen bonding between the adjacent complex molecules. In contrast, Complex 2 crystallized into a centrosymmetric monoclinic space group, P21/c (No. 14). The nickel(II) ion is coordinated by (N2O)2 donor atoms from two H2Ll-phe tridentate ligands. The coordination geometry around the nickel(II) ion is described as octahedral. In the crystal, 2 consists of [Ni(HLD-phe)2] and [Ni(HLl-phe)2] molecule that are related and forms a heterochiral 3D structure via hydrogen bonding through the crystal solvents.