A Silylene-Borane Lewis Pair as a Tool for Trapping a Water Molecule: Silanol Formation and Dehydrogenation.

The Lewis acid B(C6 F5 )3 and the cyclic silane (ArN 2 Si)3 (1) (ArN =o-(CH3 )2 NCH2 C6 H4 ) are useful precursors to access the silylene(II)-borane adduct ArN 2 Si-B(C6 F5 )3 (2). Treatment of 2 with water led to coordination and gave the Lewis pair (ArN 2 H2 O)Si-B(C6 F5 )3 (3) that exhibits a hydrogen-bond-stabilized silanol unit. It can be converted into the siloxane [(HArN )2 SiOB(C6 F5 )3 ]2 O (6) by dehydrogenation in the presence of a base. Heteronuclear NMR spectroscopic data to characterize the compounds were supported by quantum-chemical calculations.