Osmium thiophene, reactions with

Although C-S bond cleavage reactions between thiophenes and osmium clusters have not been observed, selenophene and tellurophene undergo ring opening reactions with [Os3(CO)io(NCMe)2] to give complexes 28a and 28b (Scheme T). " It is likely that the sulfur-extrusion reactions of iron and ruthenium carbonyl clusters with thiophenes proceed via ring-opened intermediates of this type. 

The high cost associated with the use of stoichiometric quantities of osmium has limited the general use of this strategy. It is interesting that a new molybdenum 7] -thiophene complex has now been developed <2003JA2024>. Its usefulness for further reactions has not yet been demonstrated. 

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