Cis-facial coordination of bis(pyrid-2-ylmethyl)amine (bpma). Synthesis, structure and spectral behaviour of [Ni(bpma)2]2+

Abstract

Nickel(II) bis-complexes of bis(pyrid-2-ylmethyl)amine (bpma) and bis(benzimidazol-2-ylmethyl)amine (bbma) have been isolated. The complexes have been characterised using IR, UV-VIS and 1H NMR spectral techniques. The pink complex [Ni(bpma)2](ClO4)2 crystallises in the orthorhombic space group Fdd2, with a=22.12(2), b=28.087(2), c=8.857(3) Å, α=β=γ=90° and Z=8. The nickel(II) atom has a slightly distorted octahedral structure in which the ligands are cis-facially coordinated. The M-Npy bond length in [M(bpma)2]2+ [M=Mn(II), Fe(II), Ni(II), Cu(II), Zn(II)] complexes decrease and then increase with increase in d-orbital population. The ligand field parameters of the new complexes are compared with those of other complexes with NiN6 chromophore. © 1998 Elsevier Science Ltd. All rights reserved.