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 (H2dmg) in THF were investigated. The reaction of [Cr(CO)6] with H2dmg resulted in the formation of the square pyramidal complex [CrO(H2dmg)2] (1). The H2dmg coordinated the metal from the two nitrogen atoms. The corresponding reactions of molybdenum and tungsten carbonyls yielded the binuclear oxo complex [(H2dmg)O2M(μ-O)2MO2(H2dmg)] (2, 3). Unusual bonding of H2dmg was observed with the formation of six membered chelates. All complexes were characterized by elemental analysis, infrared, mass and 1H 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.