Isolable T‐Shaped Planar Silyl Anion

Abstract Silyl anions have garnered significant attention due to their synthetic abilities. However, previously reported silyl anions have been limited to either trigonal‐pyramidal or trigonal‐planar geometries, which confine them primarily as nucleophiles in substitution reactions. Herein, we report the isolation of the unprecedented T‐shaped planar silyl anion salt 2 by employment of a geometrically constrained triamido pincer ligand. Theoretical calculations disclosed that the silicon centre in 2 possesses both a lone pair of electrons and an empty 3p z orbital. In addition to nucleophilic substitution reactions with Ph 3 PAuCl and W(CO) 6 , 2 readily undergoes oxidative additions with CO 2 and 2,6‐dimethylphenylisonitrile at room temperature. Furthermore, under mild conditions, compound 2 cleaves C sp2 −H, C sp2 −H, and H−H bonds in 1,2,4,5‐tetrafluorobenzene, an intramolecular i Pr group, and dihydrogen, representing the first examples of C−H and H−H activations mediated by a silyl anion, respectively. This work unveils new reactivity of silyl anions owing to the non‐classical geometry and electronic structure.