Diverse Structures and Remarkable Oxidizing Ability of Triarylbismuthane Oxides. Comparative Study on the Structure and Reactivity of a Series of Triarylpnictogen Oxides

A systematic series of triarylbismuthane oxides was prepared in order to disclose their
structure and reactivity, which have been compared with those of lighter pnictogen
counterparts. X-ray crystallographic analysis of tris(2-methoxyphenyl)bismuthane oxide and
tris(2-methoxyphenyl)stibane oxide revealed that they exist as dimers with a flat bis(μ-oxo)
ring, implying that the polarized Bi+−O- and Sb+−O- bonds aggregate to attain electrostatic
stabilization. In sharp contrast to their phosphorus, arsenic, and antimony counterparts,
triarylbismuthane oxides are thermally unstable and possess a high oxidizing ability. In
particular, the bismuthane oxides bearing ortho-substituted aryl ligands oxidized primary
and secondary alcohols to aldehydes and ketones, respectively, with high efficiency under
mild conditions.