A NEW MODIFICATION OF POLYMERIC 1/2 COMPLEX OF COPPER(II) AZIDE WITH PYRIDINE CONTAINING SIMULTANEOUS MU(1,1) AND MU(1,3) BRIDGING AZIDO LIGANDS BETWEEN COPPER(II) CENTERS

A new modification of the polymeric [Cu(pyridine)(2)(N-3)(2)](n), complex has been synthesized and characterized by spectroscopic and X-ray crystallographic methods. The structure of the monoclinic crystals contains two copper(II) centres occupying special positions. Cu(1) and also N(1), C(3) of pyridine molecule 1, and N(2), C(6) of pyridine molecule 2 are located on a two-fold rotation axis at [1/2, y, 1/4]. Cu(2) is located at the inversion centre [3/4, 3/4, 1/2]. Both copper(II) centres are six-coordinated and the coordination polyhedra are distorted tetragonal bipyramids. Both copper(II) atoms are simultaneously bridged by mu(1,1) and mu(1,3) azido ligands [Cu-N from 2.001(5) to 2.660(4) Angstrom]. The mu(1,3) bridging azido ligand is symmetrical whereas the mu(1,1) group is asymmetric but both are almost linear [178.5(5) and 176.4(5)degrees, respectively]. The IR spectrum reveals two different azido ligands and the electronic spectrum is presented and discussed.