Ruthenium Complexes Containing Two Ru−(η2-Si−H) Bonds: Synthesis, Spectroscopic Properties, Structural Data, Theoretical Calculations, and Reactivity Studies

Abstract

The bis(dihydrogen) complex RuH2(H2)2(PCy3)2 (1) reacts with the disilanes (R2SiH)2X to produce the dihydride complexes [RuH2{(η2-HSiR2)2X}(PCy3)2] (with R = Me and X = O (2a), C6H4 (3), (CH2)2 (4), (CH2)3 (5), OSiMe2O (6)) and R = Ph, X = O (2b)). In these complexes, the bis(silane) ligand is coordinated to ruthenium via two σ-Si−H bonds, as shown by NMR, IR, and X-ray data and by theoretical calculations. 3, 4, and 6 were characterized by X-ray diffraction. In the free disilanes the Si−H bond distances and the JSi-H values are around 1.49 A and 200 Hz, respectively, whereas in the new complexes the values are in the range 1.73−1.98 A and 22−82 Hz, respectively for the σ-Si−H bonds. The importance of nonbonding H···Si interactions, which control the observed cis geometry of the two bulky PCy3 ligands, is highlighted by X-ray data and theoretical calculations. The series of bis(silane) model complexes, RuH2{(η2-HSiR2)2X}(PR‘3)2, with X = (CH)2, C6H4, (CH2)n, O, and OSiH2O, and with R and R‘ = H or Me, was...