Metal complexes of tridentate hybrid ligands. V. Nickel complexes of ligands containing the donor sequence As-N-N(heterocyclic)

Abstract

The compounds obtained by the interaction of four new hybrid tridentate ligands, each containing the donor sequence As-N-N, with nickel(II) salts are described. The four ligands were obtained by the Schiff base condensation of a o-dialkylarsinoaniline and either pyridine-2-aldehyde or 6-methylpyridine-2-aldehyde. The main types of complex obtained were: 1. bis-ligand complexes of the type Ni(ligand) 2Y 2 (where Y = ClO 4 or BPh 4 and for some ligands NO 3). 2. mono-ligand complexes of the type Ni ligand X 2 (where X = Cl, Br, I or NCS and for some ligands NO 3). All the physical measurements undertaken indicate that the bis-complexes are high-spin octahedral in structure. The mono-complexes appear to possess a high-spin five-coordinate stereochemistry in the case of the chloro and bromo-complexes. The iodides all appear to possess the same structure, except for one case in which a diamagnetic four-coordinate stereochemistry obtains. The thiocyanate complexes all appear to be polymeric octahedral compounds.