Use of 6-methylpyridine-2-carbaldehydeoxime in nickel(ii) carboxylate chemistry: synthetic, structural and magnetic properties of penta and hexanuclear complexes

Abstract

The use of 6-methylpyridine-2-carbaldehydeoxime ligand (6-mepaoH), in nickel(II) chemistry has been investigated and three new clusters isolated in mild conditions. Depending on the nature of the metal starting salts and the reaction conditions, the Ni^II/6-mepaoH system has provided access to the complexes [Ni₆(O₂CPh)₆(6-mepao)₆] (1), [Ni₆(O₂CMe)₆(6-mepao)₆] (2) and [Ni₅(3-Cl-BzO)₄(6-mepao)₄(6-mepaoH)₂(N₃)₂] (3), where 3-Cl-BzO⁻ is the 3-chlorobenzoate anion. Compounds 1 and 2 are two new members of the [Ni₆(O₂C-R)(oximato)₆] family of hexanuclear complexes whereas 3 exhibits an unusual irregular bowtie topology including end-on azido bridges. The structures of the three compounds have been determined by single-crystal X-ray crystallography. Variable-temperature dc magnetic susceptibility studies were carried out for 1–3. The data indicate antiferromagnetic exchange for complexes 1 and 2 and ferrimagnetic interaction for complex 3.