Hypervalent bond formation in halogeno(2-acylphenyl)bismuthanes

Article abstract of DOI:10.1021/om00008a036

Hypervalent bond formation has been found to occur at bismuth as the hypervalent center. The transformation of (2-acetylphenyl)bis(4-methylphenyl)bismuthane (2b) to (2-acetylphenyl)bromo(4-methylphenyl)bismuthane (3b) brings about a noticeable change in the electronic nature of the carbonyl function in the 2-acetylphenyl group, which is sensitively reflected in the IR, ¹H, and ¹³C NMR spectra of compound 3b. These spectral changes may be rationalized in terms of the formation of a hypervalent O-Bi-Br bond through intramolecular coordination of the carbonyl oxygen atom to the bismuth center. X-ray crystallography of 3b has confirmed this interpretation.