Co-ordination complexes containing multidentate ligands. Part II. Five-co-ordinate nickel(II) and cobalt(II) complexes containing tridentate ligands with Group VB donors

Abstract

The ligands L, bis(o-diphenylarsinophenyl)phenylarsine (ptas) and bis(o-diphenylarsinophenyl)phenylphosphine (pdap) form low-spin five-co-ordinate complexes of formulae [Ni₂L₃(H₂O)](ClO₄)₄, [NiLX₂](X = Br or I), and [CoLX₂](X = Br or NCS). I.r. and visible spectra have been used in assigning square-pyramidal structures to the complexes. The complexing ability of these ligands is compared with that of similar ligands with aliphatic substituents on the arsenic atoms.