Stibinyl and bismuthinyl radicals are recognized as representative intermediates of antimony and bismuth compounds, but still elusive in the condensed phase. We successfully synthesized persistent stibinyl and bismuthinyl radicals in solution by facile dissociation of the corresponding dimers with bulky substituents. We characterized the radicals by NMR and UV/Vis spectroscopy and estimated the thermodynamic parameters for the dissociation equilibria. The radicals show n→p (HOMO→SOMO) transition bands at 497 nm (stibinyl) and 543 nm (bismuthinyl) in 3-methylpentane and react with a stable nitroxyl radical to give the cross-radical coupling products in good yields. Persistent: The facile dissociation of distibines and dibismuthines with bulky bidentate alkyl groups leads to the corresponding persistent radicals in solution. The stibinyl and bismuthinyl radicals were spectroscopically characterized, and the thermodynamic parameters for their dissociation equilibria were estimated. The radicals reacted with a stable nitroxyl radical to give the cross-radical coupling products in good yields.
- persistent radicals
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