Synthesis and spectral and structural characterization of a bridging chloropicolinatocopper(II) complex, Cu(C5H4NCOO)Cl

Abstract

The title complex of copper(II) chloride with picolinic acid was prepared and characterized by spectroscopic and X-ray crystallographic methods. The complex, Cu(C5H4NCOO)Cl, crystallizes tetragonal, space group P42/n (No. 86),a=976.4(1),c=1499.6(4) pm,N=8;Rw=0.048 for 543 observed MoKα diffractometer data. In the structure of the complex two μ-chloro bridges form only slightly bent Cu2Cl2 rings [Cu-Cl=224.2(4) and 275.6(4) pm] with Cu...Cu separation of 359.4(2) pm and Cl...Cl separation of 348.7(5) pm. These edge-sharing copper coordination polyhedra are further linked via the N and O donor atoms of the picolinato anions at Cu-N distances of 199.6(12) pm and Cu-O bond lengths of 195.7(8) and 200.6(10) pm, to form a two-dimensional layer structure in which these layers are arranged along theab plane. Each picolinate anion functions as a tetra-dentate ligand: N(1) and O(2) are coordinated to the same Cu(II) center whereas O(1) is bonded to a neighbouring Cu(II) center. O(2) is further bonded to the latter Cu(II) center at a long Cu-O distance of 256.5(8) pm. The electronic, infrared and Raman spectra of the solid complex are reported and discussed.