Photochemical reactions of chromium, molybdenum and tungsten hexacarbonyls with dimethylglyoxime

Sunlight irradiation of the reactions of [M(CO)(6)], M = Cr, Mo and W with dimethylglyoxime (H(2)dmg) in THF were investigated. The reaction of [Cr(CO)(6)] with H(2)dmg resulted in the formation of the square pyramidal complex [CrO(H(2)dmg)(2)] (1). The H,dmg coordinated the metal from the two nitrogen atoms. The corresponding reactions of molybdenum and tungsten carbonyls yielded the binuclear oxo complex [(H(2)dmg)O2M(mu-O)(2)Mo-2(H(2)dmg)] (2, 3). Unusual bonding of H(2)dmg was observed with the formation of six membered chelates. All complexes were characterized by elemental analysis, infrared, mass and H-1 NMR spectroscopy. The UV-vis spectra of the complexes showed visible bands due to ligand-to-metal charge transfer. Thermal properties of the complexes were investigated by thermogravimetry (TG) technique. (c) 2005 Elsevier B.V. All rights reserved.