Synthesis, structural and spectral characterization of two polymeric complexes of 2-chloropyridine and 3-benzoylpyridine with copper(II) azide;: [Cu(2-chloropyridine)(N3)2]n and [Cu(3-benzoylpyridine)2(N3)2]n

Two new polymeric mixed ligand complexes of copper(II) azide with 2-chloropyridine (1) and 3-benzoylpyridine (3) have been prepared and characterized by crystallographic and spectroscopic methods. The 1:I complex of 2-chloropyridine features penta-coordinate copper centers and two mu(1, 1) bridging azido ligands forming Chains of polyhedra along the a-axis of the unit cell. In the 1:2 complex, 2, two copper atoms are located at different inversion centers, The coordination geometries of both copper atoms may be described as distorted tetragonal bipyramids and both azides serve as mu(1, 3) bridging ligands giving rise to chains of polyhedra. The IR and Raman spectra are reported and vibrational bands of diagnostic values compared with those of parent ligands and correlated with the structures of the complexes. The solid and solution electronic spectra of 1 and 2 display strong absorptions due to N-3(-) --> Cu-II charge transfer transitions. The EPR spectra of powder samples and DMF solutions are recorded at both room temperature and 77 K. (C) 1998 Elsevier Science Ltd. All rights reserved.