The 2-Arsaethynolate Anion: Synthesis and Reactivity Towards Heteroallenes

The synthesis and isolation of the 2-arsaethynolate anion, AsCO-, and its subsequent reactivity towards heteroallenes is reported. Reactions with ketenes and carbodiimides afford four-membered anionic heterocycles in formal [2+2] cycloaddition reactions. By contrast, reaction with an isocyanate yielded a 1,4,2-diazaarsolidine-3,5-dionide anion and the unprecedented cluster anions As-10(2-) and As-12(4-). These preliminary reactivity studies hint at the enormous potential synthetic utility of this novel anion, which may be employed as an arsenide (As-) source.