Syntheses, X-ray structures, spectroscopic and magnetic studies of two newpolymeric copper(II)) azide complexes; [Cu(3-ethylpyridine)(2)(N-3)(2)](n)and [Cu(4-ethylpyridine)(2)(N-3)(2)](n)

Two new 1:2 polymeric complexes of copper(II) azide with 3-ethylpyridine (I ) and 4-ethylpyridine (2), have been synthesized and characterized by spect roscopic and crystallographic methods. The structure of complex (1) contain s a dimeric [Cu(3-Etpy)(2)(N-3)(2)](2) unit and a monomeric [Cu(3-Etpy)(2)( N-3)(2)] unit. Each copper atom in the dimeric unit attains a five coordina tion environment, whereas the copper atom in the second unit has an elongat ed octahedral geometry. In complex (2), each copper atom in the asymmetric unit is coordinated to the end nitrogens of two mu(2)-1,3 azido ligands, a pair of trans 4-Etpy molecules and a nitrogen atom of a terminal azide grou p. This same nitrogen atom further links a neighboring copper atom at a lon g Cu-N distance of 2.920(7) Angstrom, thus connecting the asymmetric units giving rise to a 2D structure. The IR and electronic spectra are reported. Strong absorption bands due to N-3 --> (CuMLCT)-M-II transitions are observ ed in spectra of solids and solutions of both complexes. Magnetic susceptib ility and EPR data of both complexes are presented and discussed. (C) 1998 Elsevier Science Ltd. All rights reserved.