Substituted phenols as ligands. Part 7. X-Ray crystal-structure analysis of bis(2-methoxy-4-nitrophenolato)bis(pyridine)nickel(II) and the electronic and magnetic properties of the isomorphous bis(2-methoxy-4-nitrophenolato)bis(pyridine)cobalt(II)

Abstract

Crystals of the title nickel(II) complex are triclinic with a= 9.642(1), b= 10.793(1), c= 12.622(1)Å, α= 85.28(1), β= 69.22(1), γ= 87.76(1)°, Z= 2. and space group P. The structure has been determined by direct methods, with Cu-K_α diffractometer data, and refined by full-matrix least squares to R 0.039 for 3 475 reflections. Both methoxy- and phenolic oxygen atoms co-ordinate to the metal and, together with the nitrogen atoms from the pyridine molecules, give the nickel atoms six-co-ordination. The d–d electronic spectrum is that expected for a six-co-ordinate complex with m3m(O_h) symmetry, in spite of the long Ni–O(CH₃) bonds, but for the isomorphous cobalt(II) complex the effect of the low symmetry is observed. Similarly, the effective magnetic moments indicate deviations from regular stereochemistry for the cobalt(II) complex but not for the nickel(II) analogue.