Organobismuth

Organobismuth compounds are organometallic species containing a carbon–bismuth bond. They include Bi(III) derivatives such as diaryl or dialkylbismuthanes and less common Bi(V) species. The carbon–bismuth bond is relatively weak compared with many other carbon–metal bonds, influencing their reactivity in synthesis.

Common classes are diaryl- and dialkylbismuthanes, and triarylbismuth derivatives such as triphenylbismuth. These species arise from substituting organometallic fragments onto a bismuth(III) center, typically starting from a bismuth(III) halide such as BiCl3 or BiBr3.

Synthesis and stability: Organobismuth reagents are typically prepared by transmetalation to a bismuth(III) source from other organometallic precursors. They vary in stability and may be sensitive to air or moisture depending on substituents; some species can decompose to elemental bismuth or bismuth oxides under harsh conditions.

Reactivity and applications: The C–Bi bond allows transfer of carbon groups in certain cross-coupling and radical processes, often under catalytic or photochemical conditions. Organobismuth reagents offer a lower-toxicity alternative to some organotin reagents and have been explored for selective arylation and alkylation steps in organic synthesis, as niche reagents for carbon–carbon bond formation.

Safety: Organobismuth compounds generally pose lower acute toxicity than many heavy-metal reagents, but they require standard laboratory handling, waste treatment, and personal protective equipment according to established safety practices.