SYNTHESIS AND CHARACTERIZATION OF A STABLE DIBISMUTHENE - EVIDENCE FOR A BI-BI DOUBLE-BOND

Treatment of an overcrowded triselenatribismane, yl)methyl)phenyl-1,3, 5-triselena-2,4,6-tribismane, with hexamethylphosphorous triamide in t oluene at 100 degrees C resulted in the quantitative formation of a st able dibismuthene [TbtBi = BiTbt, where Tbt is 2,4,6-tris(bis(trimethy lsilyl)methyl)phenyl], a compound containing a double bond formed betw een two bismuth atoms. The compound formed as deep purple crystals upo n cooling. Ultraviolet-visible and Raman spectra, x-ray crystallograph ic structural analysis, and theoretical calculations provided evidence for the double bond character of the Bi-Bi bond.