Template synthesis and structure of Co(II), Ni(II), and Cu(II) complexes with pyridoxilydenetaurinate Schiff base ligand

Abstract

Abstract Co(II), Ni(II), and Cu(II) complexes with a Schiff base ligand pyridoxylidenetaurinate (L − ) were prepared by a template reaction of pyridoxal (3-hydroxy-5-(hydroxymethyl)-2-methylpyridine-4-carbaldehyde), taurine (2-aminoethane-1-sulfonic acid), and the corresponding metal acetate in water–ethanol solution. Composition of the product was [ML 2 (H 2 O) 2 ] for all three central metals. Coordination geometry varied from weakly distorted octahedral (Co, Ni) to strongly distorted octahedral (Cu) with trans arrangement of both water molecules and imine N atoms. Each bidentate ligand formed one chelate ring via iminic N and phenolic O donor atoms. The complexes were characterised by elemental analysis, FTIR spectroscopy, and XRD crystal and powder analyses. All complexes crystallize in monoclinic system with space group P 2 1 / c . IR spectra of the complexes showed changes typical for Schiff base coordination, comparing with IR spectrum of the ligand.