Sulphur dioxide complexes of molybdenum and tungsten

Abstract

The first well authenticated complexes of molybdenum and tungsten containing co-ordinated sulphur dioxide are described. Reaction of the compounds M(CO)₃B py, M(CO)₃BPPh₃, or M(CO)₃py₃[M = Mo or W; B = 2,2′-bipyridyl (bipy) or 1,10-phenanthroline (phen); py = pyridine] with gaseous sulphur dioxide in dichloromethane leads to derivatives of the type M(CO)₃B(SO₂) and M(CO)₃ py₂(SO₂). The compounds Mo(CO)₃ bipy py, [Mo(CO)₂bipy pyπ-allyl]BF₄, or Mo(CO)₂ bipy(PPh₃)₂ react in liquid sulphur dioxide to yield the product, Mo(CO)₂ bipy(SO₂)₂. By reaction of the bis(triphenylphosphine) derivatives with gaseous sulphur dioxide, the mixed complexes Mo(CO)₂ bipyPPh₃(SO₂) and Mo(CO)₂ phenPPh₃(SO₂) are formed.