The crystal and molecular structure of bis(histidino)nickel(II) monohydrate

Abstract

The structure of bis(histidino)nickel(II) monohydrate has been determined from three-dimensional X-ray diffraction data. The crystals are orthorhombic with a= 15·18, b= 13·05, c= 7·72 Å, and space-group Aba2. Positional and anisotropic thermal parameters have been refined by least-squares methods; the final R factor is 0·082. The crystal contains molecules of bis-(D-histidino)nickel and bis-(L-histidino)nickel, related to each other by glide planes. The nickel atoms lie on two-fold axes and are octahedrally co-ordinated by the amino-nitrogen, the imidazole nitrogen, and a carboxyl oxygen of each histidine group, at 2·11, 2·09, 2·11 Å, respectively (e.s.d. ca. 0·01 Å).