A Monoanionic Arsenide Source: Decarbonylation of the 2‐Arsaethynolate Anion upon Reaction with Bulky Stannylenes

We report fundamental studies on the reactivity of the 2‐arsaethynolate anion (AsCO(−)), a species that has only recently become synthetically accessible. The reaction of AsCO(−) with the bulky stannylene Ter(2)Sn (Ter=2,6‐bis[2,4,6‐trimethylphenyl]phenyl) is described, which leads to the unexpected formation of a [Ter(3)Sn(2)As(2)](−) cluster compound. On the reaction pathway to this cluster, several intermediates were identified and characterized. After the initial association of AsCO(−) to Ter(2)Sn, decarbonylation occurs to give an anion featuring monocoordinate arsenic, [Ter(2)SnAs](−). Both species are not stable under ambient conditions, and [Ter(2)SnAs](−) rearranges to form [TerSnAsTer](−), an unprecedented anionic mixed Group 14/15 alkene analogue.