NEUTRAL, CATIONIC AND DICATIONIC 7-COORDINATE COMPLEXES OF MOLYBDENUM(II) AND TUNGSTEN(II) CONTAINING MONODEUTATE AND BIDENTATE NITROGEN DONOR LIGANDS

The seven-coordinate complexes [MI2(CO)3(NCMe)2] (M=Mo or W) react with two equivalents of L(L=py, 4Me-py, 3Cl-py or 3Br-py) or one equivalent of NN {NN=2,2′-bipyridine(bipy), 1,10-phenanthroline(phen), 5,6-dimethyl-1, 10-phenanthroline (5,6-Me2-1, 10-phen), 5-Nitro-1, 10-phenanthroline (5-NO2-1, 10-phen) and C6H4(o-NH2)2 (o-diam) (for M=Mo only)} in CH2Cl2 at room temperature to give the substituted products [MI2(CO)3L2] or [MI2(CO)3(NN)] (1-17) in high yield. The compounds [MI2(CO)3(NCMe)2] react with two equivalents of NN (for M=W, NN=bipy; for M=Mo, NN=phen) to give the dicationic salts [M(CO)3(NN)2]2I (18-19). The compounds [MI2(CO)3(NCMe)2] (M=Mo or W) react with two equivalents of 5,6-Me2-1, 10-phen to yield the monocationic dicarbonyl compounds [MI(CO)2(5,6-Me2-phen)2]I (20 and 21). The dicationic mixed ligand complexes [M(CO)3(bipy)(5,6-Me2-phen)]2I (22 and 23) are prepared by reacting [MI2(CO)3(NCMe)2] with one equivalent of bipy, followed by an in situ reaction with 5,6-Me2-1, 10-phen to afford the products 22 and 23. The complexes (1-23) described in this paper have been characterised by elemental analysis (C, H and N), i.r. spectroscopy and, in selected cases,1Hn.m.r. spectroscopy. Magnetic susceptibility measurements show the compounds to be diamagnetic. © 1990 Chapman and Hall Ltd.