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

Abstract Copper(II) complex with dl -piperidine-3-carboxylic acid ( dl -Hpipe-3):[Cu( dl -pipe-3) 2 (H 2 O)] and cobalt(II) and nickel(II) complexes with piperidine-4-carboxylic acid (Hpipe-4):[M(Hpipe-4) 2 (H 2 O) 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 (H 2 O)] 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 (H 2 O) 4 ]Cl 2 are monoclinic with space group P 2 1 / n . In these complexes the metal atom is in an octahedral geometry ligated by two carboxylato oxygen atoms and four water molecules.