Characterization and crystal structures of copper(II), cobalt(II), and nickel(II) complexes with two kinds of piperidine carboxylic acids

Copper(II) complex with DL-piperidine-3-carboxylic acid (DL-Hpipe-3): [Cu(DL-pipe-3)(2)(H2O)] and cobalt(II) and nickel(II) complexes with piperidine-4-carboxylic acid (Hpipe-4):[M(Hpipe-4)(2)(H2O)(4)]Cl-2 (M: Co, Ni) have been prepared and characterized by means of IR and powder diffuse reflection spectra, thermal analysis, and magnetic susceptibility. The crystal structures of these complexes have been determined by X-ray diffraction. The crystal of [Cu(DL-pipe-3)(2)(H2O)] is orthorhombic with the space group Pbcn. The copper atom is in a square pyramidal geometry, ligated by two carboxylato oxygen atoms, two nitrogen atoms, and a water molecule. One molecule of this complex consists of either D-piperidine-3-carboxylic acid or L-piperidine-3-carboxylic acid. The crystals of [M(Hpipe-4)(2)(H2O)(4)]Cl-2 are monoclinic with space group P2(1)/n. In these complexes the metal atom is in an octahedral geometry ligated by two carboxylato oxygen atoms and four water molecules. (C) 2002 Elsevier Science B.V. All rights reserved.