SYNTHESIS AND STRUCTURAL DETERMINATION OF AZIDOTETRAKIS-(3-ETHYL-4-METHYLPYRIDINE)COPPER(II) PERCHLORATE AND DOTETRAKIS(3-ETHYL-4-METHYLPYRIDINE)]DICOPPER(II), [CU(BETA-COLLIDINE)(4)(N-3)](CLO4) AND [CU(BETA-COLLIDINE)(2)(N-3)(2)](2)

The preparation and structural characterizations of two new copper(II) azido complexes of 3-ethyl-4-methylpyridine (beta-collidine), namely azido tetrakis(beta-collidine) copper(II) perchlorate (1) and ido-[dia zido-tetrakis(beta-collidine)]dicopper(II) (2) are described. The spec tral results suggest an ionic perchlorate and terminal azido group in complex I and different asymmetric azides in 2. The structure of 1 con sists of isolated [Cu(beta-collidine)(4)(N-3)](+) cations and ClO4- an ions. The copper atom in the cation is in a tetragonal pyramidal envir onment with four collidine ligands occupying the basal sites [Cu-N = 2 .033(4) Angstrom] and a terminal azido ligand at the apical position w ith a Cu-N distance of 2.141(6) Angstrom. The centrosymmetric binuclea r molecule 2 features monodentate collidine ligands, di-mu(1,1)-azido- bridged Cu2N2 rings, terminal azido ligands and distorted square pyram idal copper(II) coordination geometry.