(μ-2,2',2'',2'''-{[Pyrazine-2,3,5,6-tetra-yltetra-kis(methyl-ene)]tetra-kis(sulfanedi-yl)}tetra-acetato)bis-[aqua-nickel(II)] hepta-hydrate.

Abstract

Reaction of the ligand 2,2',2'',2'''-{[pyrazine-2,3,5,6-tetra-yltetra-kis-(methyl-ene)]tetra-kis-(sulfanedi-yl)}tetra-acetic acid (H4L1), with NiCl2 leads to the formation of a binuclear complex, (μ-2,2',2'',2'''-{[pyrazine-2,3,5,6-tetra-yltetra-kis-(methyl-ene)]tetra-kis-(sulfanedi-yl)}tetra-acetato-κ5 O,S,N 1,S',O':κ5 O'',S'',N 4,S''',O''')bis[aqua-nickel(II)] hepta-hydrate, {[Ni2(C16H16N2O8S4)(H2O)2]·7H2O} (I). It crystallizes with two half mol-ecules in the asymmetric unit. The complete mol-ecules are generated by inversion symmetry, with the center of the pyrazine rings being located at crystallographic centres of inversion. The ligand coordinates two NiII ions in a bis-penta-dentate manner and the sixfold coordination sphere of each nickel(II) atom (NiS2O3N) is completed by a water mol-ecule. The complex crystallized as a hepta-hydrate. The binuclear complexes are linked by Owater-H⋯Ocarbon-yl hydrogen bonds, forming layers parallel to the (101) plane. This layered structure is additionally stabilized by weak C-H⋯O hydrogen bonds. Further O-H⋯O hydrogen bonds involving binuclear complexes and solvent water mol-ecules, together with weak C-H⋯S hydrogen bonds, link the layers to form a supra-molecular framework.