Ferromagnetic coupling between semiquinone type tridentate radical ligands mediated by metal ions

Reactions between 3,5-di-tert-butylcatechol, aqueous ammonia and titanium, vanadium, germanium, and tin salts yield neutral bis- complexes of the resulting tridentate Schiff base biquinone ligand. On the basis of their magnetic, electrochemical, and spectral properties all the isolated compounds can be formulated as metal(IV) derivatives of the dinegative radical ligand Cat-N-SQ, M(Cat-N-SQ) 2 . This suggestion is supported by the structural characterization of the titanium and vanadium derivatives