A new series of 1D polymeric nickel(II) complex cations of pyridine derivative ligands with a single μ-1,3 azide bridge and X-ray crystal structure and magnetic properties of polymeric {[Ni(4-ethylpyridine)4(N3)n](PF6)n}

A new series of polymeric nickel(II) complex cations of the formula [NiL4(N-3)](PF6), for L = pyridine, 4-methyl-, 4-ethyl-, 3-chloro-. 3-bromo- and 3-hydroxy-pyridine, have been prepared and characterized. Solid state electronic spectra suggest six-coordinate nickel(II) in all complexes. IR spectral results reveal the existence of symmetrical azido ligands and PF6- counter ions in these complexes. X-ray crystal structure determination has shown the complex for L = 4-ethylpyridine (1) to contain a polymeric [NiL4(N-3)](+) cation and PF6- anions. In the cation each nickel(II) atom is coordinated by four nitrogen atoms from the pyridine ligands and two nitrogen atoms each from a mu-1,3 bridging azide giving rise to ID polymeric chains of six-coordinate Ni(II) polyhedra. The azide ligand is symmetrical [N-1-N-2 = N-2-N-3 = 1.152 and N-1-N-2 = 1.164, N-2-N-3 = 1.162 Angstrom] and linear [NNN angles = 178degrees and 180degrees] within the experimental error. The magnetic susceptibilities of 1 in the range of 2-300 K, have been measured and discussed. (C) 2002 Published by Elsevier Science Ltd.