Synthesis and characterization of a new series of 1D cobalt(II) complexes of pyridine derivative ligands with a single azido bridge and X-ray crystalstructure of catena-(mu-N-3)[Co(4-methylpyridine)(4)](PF6)

A new series of polymeric cobalt(II) azido complex cations of the formula [ CoL4(N-3)]PF6-nH(2)O (n = 0 or 1), for L = some pyridine derivative ligands , have been prepared and characterized. Solid state electronic spectra sugg est six-coordinated cobalt(II) in all complexes. IR spectral results reveal the existence of symmetrical azido ligand, except for complexes of L = 3-E tpy and 4-Etpy(red) which contain asymmetrical azides, as well as PF, count er ions in all complexes. X-ray crystal structure determination has shown t he complex for L = 4-methylpyridine to contain polymeric [CoL4(N-3)](+) cat ion and PF6- anions. In the cation, each cobalt(II) atom is coordinated by four nitrogen atoms from the pyridine ligands and two nitrogen atoms each f rom a mu-(1,3)-bridging azide giving rise to polymeric chains(1D) of six-co ordinate Co(II) polyhedra. The azide ligand is symmetrical [N-1-N-2 = N-2-N -3 = 1.170(3) Angstrom] and linear within experimental error. (C) 1999 Else vier Science Ltd. All rights reserved.