Antimony pentachloride oxidation of arenetricarbonyl complexes of molybdenum and tungsten and a new route to substituted halogenocarbonyls

Abstract

The complexes M(CO)₃ arene (M = Cr, Mo, or W, arene = hexamethylbenzene (hmb); M = Mo or W, arene = mesitylene, durene, or p-cymene) react with antimony pentachloride in dichloromethane to give the orange-red ionic products [M(CO)₃ arene Cl]SbCl₆. For the complexes where M = Mo or W and arene = hmb, the products were fully characterised as the hexachloroantimonate and tetraphenylborate salts but in all other cases the products could not be obtained pure. [M(CO)₃(HMB)Cl]BPh₄ reacts with certain monodentate ligands to give the diamagnetic monomeric product M(CO)₃L₂Cl₂(L = PPh₃ or AsPh₃) together with some M(CO)₃ hmb, whereas with bidentate ligands the ionic derivatives [M(CO)₂(LL)₂Cl]BPh₄[LL = 2,2′-bipyridyl, 1,10-phenanthroline, or o-phenylenebisdimethylarsine] are obtained. With the terdentate bis-(o-dimethylarsinophenyl)methylarsine simple replacement of the hmb group occurs to give [M(CO)₃(o-triars)Cl]BPh₄.