SYNTHESIS, STRUCTURAL AND SPECTRAL CHARACTERIZATION OF 2 POLYMERIC COMPLEXES OF 2-CHLOROPYRIDINE AND 3-BENZOYLPYRIDINE WITH COPPER(II) AZIDE - [CU(2-CHLOROPYRIDINE)(N-3)(2)](N) AND [CU(3-BENZOYLPYRIDINE)(2)(N-3)(2)](N)

Two new polymeric mixed ligand complexes of copper(II) azide with 2-ch loropyridine (1) and 3-benzoylpyridine (3) have been prepared and char acterized by crystallographic and spectroscopic methods. The 1:I compl ex of 2-chloropyridine features penta-coordinate copper centers and tw o mu(1, 1) bridging azido ligands forming Chains of polyhedra along th e a-axis of the unit cell. In the 1:2 complex, 2, two copper atoms are located at different inversion centers, The coordination geometries o f both copper atoms may be described as distorted tetragonal bipyramid s and both azides serve as mu(1, 3) bridging ligands giving rise to ch ains of polyhedra. The IR and Raman spectra are reported and vibration al bands of diagnostic values compared with those of parent ligands an d correlated with the structures of the complexes. The solid and solut ion 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.