Mechanochemical Dissociation of Singlet Carbene–CS ₂ Adducts

Abstract Owing to the extensive application of singlet carbenes, their generation through the release of small molecules from stable adducts is attracting increasing research interest. This study explores the mechanochemical release of CS 2 from Carbene – CS 2 adducts formed by three distinct singlet carbenes: cyclic (alkyl)(amino)carbene ( CAAC ); N‐heterocyclic carbene ( NHC ); and N,N’‐diamidocarbene ( DAC ). Under ball‐milling conditions, these adducts exhibit notably different reactivities; DAC – CS 2 releases CS 2 completely within 20 min, NHC – CS 2 has a slower release rate, while CAAC – CS 2 decomposes into a complex mixture. DFT calculations reveal that the release of CS 2 from CAAC – CS 2 requires the highest activation energy (32 kcal/mol), suggesting that it is inaccessible under the reaction conditions. This is likely because of the higher HOMO energy of CAAC , which correlates with a stronger bond with CS 2 , thereby limiting its dissociation. This study highlights how the electronic structures of carbenes influence their interactions with small molecules, paving the way for controlling the reactivity of carbene–small‐molecule adducts.