A Stable Two-Coordinate Acyclic Silylene

Simple two-coordinate acyclic silylenes, SiR2, have hitherto been identified only as transient intermediates or thermally labile species. By making use of the strong σ-donor properties and high steric loading of the B­(NDippCH)2 substituent (Dipp = 2,6-iPr2C6H3), an isolable monomeric species, Si­{B­(NDippCH)2}­{N­(SiMe3)­Dipp}, can be synthesized which is stable in the solid state up to 130 °C. This silylene species undergoes facile oxidative addition reactions with dihydrogen (at sub-ambient temperatures) and with alkyl C–H bonds, consistent with a low singlet–triplet gap (103.9 kJ mol–1), thus demonstrating fundamental modes of reactivity more characteristic of transition metal systems.