Facile Access to NaOC≡As and Its Use as an Arsenic Source To Form Germylidenylarsinidene Complexes

A facile, one‐pot synthesis of [Na(OC≡As)(dioxane)_x ] (x =2.3–3.3) in 78 % yield is reported through the reaction of arsine gas with dimethylcarbonate in the presence of NaO^t Bu and 1,4‐dioxane. It has been employed for the synthesis of the first arsaketenyl‐functionalized germylene [LGeAsCO] ( 2 , L=CH[CMeN(Dipp)]₂; Dipp=2,6‐ⁱ Pr₂C₆H₃) from the reaction with LGeCl ( 1 ). Upon exposure to ambient light, 2 undergoes CO elimination to form the 1,3‐digerma‐2,4‐diarsacyclobutadiene [L₂Ge₂As₂] ( 3 ), which contains a symmetric Ge₂As₂ ring with ylide‐like Ge=As bonds. Remarkably, the CO ligand located at the arsenic center of 2 can be exchanged with PPh₃ or an N‐heterocyclic carbene ^{i Pr}NHC donor (^{i Pr}NHC=1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene) to afford the novel germylidenylarsinidene complexes [LGe‐AsPPh₃] ( 4 ) and [LGe‐As(^{i Pr}NHC)] ( 5 ), respectively, demonstrating transition‐metal‐like ligand substitution at the arsinidene‐like As atom. The formation of 2 – 5 and their electronic structures have been studied by DFT calculations.