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(N 3) n](PF 6) n}

Abstract

A new series of polymeric nickel(II) complex cations of the formula [NiL 4(N 3)](PF 6), 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 PF 6 − counter ions in these complexes. X-ray crystal structure determination has shown the complex for L=4-ethylpyridine ( 1) to contain a polymeric [NiL 4(N 3)] + cation and PF 6 − 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 μ-1,3 bridging azide giving rise to 1D 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 Å] and linear [NNN angles=178° and 180°] within the experimental error. The magnetic susceptibilities of 1 in the range of 2–300 K, have been measured and discussed.