Synthesis, spectroscopy, and magnetic characterization of copper(II) and cobalt(II) complexes with 2-amino-5-bromopyridine as ligand

The synthesis, spectroscopic, and magnetic characterization of two new copper(II) and cobalt(II) complexes are described. Both two compounds have the general formula [M(L)(2)(Cl)(2)] (M = Cu (I), Co (II); L = 2-amino-5-bromopyridine). These complexes were prepared in one-step synthesis and characterized by elemental analysis, FT-IR, UV-Vis, and EPR spectroscopy. Moreover, the single crystal structure of complex I was studied by the X-ray diffraction method. This compound consists of mononuclear units consisting of two ligands linked to metal via the nitrogen of pyridine ring. The UV-Vis spectra of copper(II) and cobalt(II) complexes show three and five absorption bands, respectively, attributed to the d-d transition of the metal ion, ligand -> metal charge transfer and pi -> pi* or n -> pi* transitions of the ligand. The FT-IR spectra show MN2Cl2 vibrations at 500-300 cm(-1). The complexes show room temperature magnetic moments of 1.78 and 4.12 mu(B) for Cu(II) and Co(II), respectively. The X-band electron spin resonance (ESR) spectra of Cu(II) complex in DMF or DMSO frozen at liquid nitrogen temperature show the typical Delta M-S = +/- 1 transition.