Activation of Ge−H and Sn−H Bonds with N‐Heterocyclic Carbenes and a Cyclic (Alkyl)(amino)carbene

A study of the reactivity of several N‐heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene 1‐(2,6‐di‐iso‐propylphenyl)‐3,3,5,5‐tetramethyl‐pyrrolidin‐2‐ylidene (cAAC(Me)) with the group 14 hydrides GeH(2)Mes(2) and SnH(2)Me(2) (Me=CH(3), Mes=1,3,5‐(CH(3))(3)C(6)H(2)) is presented. The reaction of GeH(2)Mes(2) with cAAC(Me) led to the insertion of cAAC(Me) into one Ge−H bond to give cAAC(Me)H−GeHMes(2) (1). If 1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene (Me(2)Im(Me)) was used as the carbene, NHC‐mediated dehydrogenative coupling occurred, which led to the NHC‐stabilized germylene Me(2)Im(Me)⋅GeMes(2) (2). The reaction of SnH(2)Me(2) with cAAC(Me) also afforded the insertion product cAAC(Me)H−SnHMe(2) (3), and reaction of two equivalents Me(2)Im(Me) with SnH(2)Me(2) gave the NHC‐stabilized stannylene Me(2)Im(Me)⋅SnMe(2) (4). If the sterically more demanding NHCs Me(2)Im(Me), 1,3‐di‐isopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene (iPr(2)Im(Me)) and 1,3‐bis‐(2,6‐di‐isopropylphenyl)‐imidazolin‐2‐ylidene (Dipp(2)Im) were employed, selective formation of cyclic oligomers (SnMe(2))( n ) (5; n=5–8) in high yield was observed. These cyclic oligomers were also obtained from the controlled decomposition of cAAC(Me)H−SnHMe(2) (3).