THE USE OF ELECTROCHEMICAL METHODS IN THE PREPARATION OF NEW MANGANESE(II) COMPLEXES OF BIDENTATE SCHIFF-BASE LIGANDS AND 1,10-PHENANTHROLINE - THE X-RAY CRYSTAL-STRUCTURE OF 1,10-PHENANTHROLINE 4-METHYL)PHENYL]-SALICYLIDENEIMINATO)MANGANESE(II)

A series of manganese(II) complexes of bidentate NO donor set Schiff b ase ligands, together with corresponding mixed complexes containing 1, 10-phenanthroline (phen), have been prepared by the electrochemical ox idation of a manganese anode in acetonitrile solutions of the Schiff b ases (HL) and phen. The complexes formed are found to be of the form [ Mn(L)(2)]. nH(2)O and [Mn(L)(2)(phen)]. nH(2)O (n = 0-3). The single-c rystal X-ray structure of [Mn(L(6))(2)(phen)] (L(6) = {N-[2-(4-methyl) phenyl]-salicylideneiminato}) reveals it to be a distorted octahedral manganese(II) complex, with the distortion occurring in the equatorial plane. Cyclic voltammetry and room-temperature magnetic studies indic ate that the monomeric structure of [Mn(L(6))(2)(phen)] is representat ive of the whole series of mixed ligand compounds, whilst the magnetic behaviour of the complexes, formulated as [Mn(L)(2)]. nH(2)O, suggest s that they may exist as polymeric species with strong antiferromagnet ic coupling between the manganese centres.