Unexpected formation of triarylbismuth diformates in the oxidation of triarylbismuthines with ozone at low temperatures

Abstract

Oxidation of triphenylbismuthine 1 with ozone in toluene at –78°C gave, unexpectedly, a high yield of triphenylbismuth diformate 3, which was also obtainable as a minor product by a similar oxidation in ethyl acetate and acetone. An X-ray crystallographic study revealed that compound 3 has C2 symmetry, the geometry around the bismuth atom being best described as a distorted trigonal bipyramid as a result of strong intramolecular interaction between the bismuth and carbonyl oxygen atoms. Treatment of compound 3 with aqueous sodium acetate or halides readily converted it into the corresponding triphenylbismuth diacetate 5 or dihalides 7–9.