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 Ter2 Sn (Ter=2,6-bis[2,4,6-trimethylphenyl]phenyl) is described, which leads to the unexpected formation of a [Ter3 Sn2 As2 ](-) cluster compound. On the reaction pathway to this cluster, several intermediates were identified and characterized. After the initial association of AsCO(-) to Ter2 Sn, decarbonylation occurs to give an anion featuring monocoordinate arsenic, [Ter2 SnAs](-) . Both species are not stable under ambient conditions, and [Ter2 SnAs](-) rearranges to form [TerSnAsTer](-) , an unprecedented anionic mixed Group 14/15 alkene analogue.