Über die Struktur von Bis-(dihydroxoboroxalendiamiddioximato)-nickel(II)-tetrahydrat

The space group of the sparingly soluble brown coloured bis-(dihydroxobor-oxalene-diamide-dioximato)-nickel(II)-tetrahydrate (C₄H₁₂N₈O₈B₂Ni · 4 H₂O) is P21/c with a = 9.25, b = 13.27, c = 6.61 Å and β = 92.7°. The structure was solved on single crystals. There are two molecules in the unit cell. Within the square planar complex the nickel atom is bonded to the four nitrogen atoms of the plane system of the two dioximato ligands (Ni? N = 1.84 ± 0.02 Å). Each of the boron atoms is tetrahedrally surrounded by two oxygen atoms belonging to the oxime groups and two hydroxyl groups (B? O = 1.50 ± 0.06 Å). Thus the complex has the conformation of a chair form. The water molecules participate in intermolecular hydrogen bonds. There is no interaction between Ni atoms.