A stable silylene in a reactive environment: Synthesis, reactivity, and silicon extrusion chemistry of a coordinatively unsaturated ruthenium silylene complex containing chloride and η3-P-C-P ligands
Abstract
Reaction of [(dcypb)ClRu(μ-Cl) Ru(dcypb)(N )] (1) with 4 equiv of the stable silylene 1,3-di-tert-butyl-l,3,2-diazasilol-2-ylidene (SiL ) yields coordinatively unsaturated RuCl(η -dcypb)(SiL ) (2). Complex 2 is a rare example of a trans-spanning diphosphine complex, this geometry resulting from an unprecedented attack of the metal on the tetramethylene ligand backbone. X-ray and solid-state P NMR and IR analysis reveal an agostic interaction between the metal and a silylene Bu group. In solution, this interaction is observed only at low temperature. Reaction of 2 with H containing trace H O yields siloxane dimer [L Si-(H)] O 3 and the ruthenium hydride-H adduct [(dcypb)(H)Ru(μ-Cl) (μ-H)Ru(dcypb)(H )] (4). Attempts to isolate 4 resulted in serendipitous crystallization of decomposition product 5, [(dcypb)(H)Ru(μ-Cl) Ru(dcypb)(N )]. X-ray analysis of 5 revealed a structure closely analogous to that of 4, in which bridging hydride is replaced by chloride, and η -H by η N . Displacement of silylene from 2 is facile: treatment with 1 atm of CO affords free SiL , accompanied by RuCl(η -dcypb)(CO) as a mixture of three isomers (6-8). 3 2 2 2 2 2 2 2 2 2 2 3 2 2 2 2 2 N 3 N 31 t N 2 2 N 3
