DINUCLEAR COMPLEXES OF COBALT(II) WITH N,N'-SUBSTITUTED DITHIOXAMIDESDERIVED FROM ALPHA-AMINO-ACIDS

The coordination behaviour of N,N'-bis(1-carboxy-methyl)dithioxamide ( GLYDTO), N,N'-bis(l-carboxy-ethyl)dithioxamide (ALADTO), N,N'-bis(1-ca rboxy-2-methylpropyl) dithioxamide (VALDTO) and N,N'-bis(1-carboxy-3-m ethylbutyl)dithioxamide (LEUDTO) has been investigated by isolating an d characterizing the dinuclear, neutral cobalt(II) complexes, [Co-2(L- 4H)(H2O)(2)] (L = GLYDTO, ALADTO, VALDTO or LEUDTO) and [Co-2(L-4H)(H2 O)(6)] (L = ALADTO or VALDTO). All ligands were characterized by mass, i.r., and H-1- and C-13-n.m.r. spectroscopy. The complexes possess di storted octahedral structures as revealed by the magnetic and electron ic (diffuse reflectance) spectral data. The i.r. data indicate that th e ligands are bis-tridentate, bis-dianions coordinated to each metal i on through the carboxylate oxygen, deprotonated thioamide nitrogen and thiocarbonyl sulphur atoms.