Addressing the Nature of Phosphinidene Sulfides via the Synthesis of P−S Heterocycles.

Abstract: The phosphorus–sulfur heterocycles 1,2‐thiaphosphetenes and phosphirene sulfides have been prepared, and represent the first structurally characterized derivatives for either class of compound. These strained P−S ring systems are formed by the reaction of a phosphinidene sulfide and alkyne. Using an internal alkyne, only the 3‐membered P^V, phosphirene sulfide was produced, whereas a terminal alkyne yielded a mixture of phosphirene sulfide and 1,2‐thiaphosphetene (P^III). Detailed computational analysis revealed that for numerous derivatives of alkynes, the corresponding 4‐membered rings are always more stable than the 3‐membered isomers. The electronic nature of “free” phosphinidene sulfides (R−P=S) is discussed based on computational results. [ABSTRACT FROM AUTHOR]