A Free Silanide from Nucleophilic Substitution at Silicon(II)

A computationally guided synthetic route to a free silanide derived from tris(3‐methylindol‐2‐yl)methane ([(tmim)Si]−) through nucleophilic substitution on the SiII precursor (Idipp)SiCl2 is reported (Idipp=2,3‐dihydro‐1,3‐bis(2,6‐diisopropylphenyl)‐1H‐imidazol‐2‐ylidene). This approach circumvents the need for strained tetrahedral silanes as synthetic intermediates. Computational investigations show that the electron‐donating properties of [(tmim)Si]− are close to those of PMe3. Experimentally, the [(tmim)Si]− anion is shown to undergo clean complexation to the base metal salts CuCl and FeCl2, demonstrating the potential utility as a supporting ligand. Relaxed bicycle: A bicyclic silanide was synthesized by nucleophilic substitution of an indolide‐based trianionic fragment on a neutral SiII precursor, avoiding strained tetrahedral SiIV intermediates. The silanide forms coordination complexes with first‐row transition‐metal salts, such as CuCl and FeCl2, suggesting the utility as a supporting ligand.