X-Ray structure and theoretical studies of RuH2(η2-H2)(η2-H-SiPh3)(PCy3)2, a complex with two different η2-coordinated σ bonds

Abstract

Weak interactions between the silicon and the hydrides are responsible for the stabilization of the title complex bearing two different coordinated s-bonds, (h 2 -H 2 ) and (h 2 -H-SiPh 3 ).

σ‐Silane Ruthenium Complexes: The Crucial Role of Secondary Interactions

“…However the overall geometry was not predictable by NMR spectroscopy, but was confirmed by DFT/B3LYP calculations on the model RuH 2 (η 2 -HSiH 3 )(η 2 -H 2 )(PH 3 ) 2 . [25] The ground state structure shows two SISHA interactions (2.071 and 2.116 Å) and an elongated σ-Si-H (1.946 Å) that is less than 0.2 Å shorter. This short difference is in agreement with the high fluxionality observed by NMR spectroscopy.…”

“…[21][22][23][24][25] Depending on the activation degree of the Si-H bond, they can be interpreted as σ-silane or silyl hydride complexes, namely RuH 2 (σ-HSiR 3 )L 2 LЈ or RuH 3 (SiR 3 )L 2 LЈ, respectively (L, LЈ = PR 3 , CO, σ-H 2 ). The NMR spectroscopic data are very similar for most of the complexes, as can be seen from In the case of symmetrical complexes (C 3 axis), the equivalency of the hydrides prevents any further interpretation regarding the bonding mode.…”

The σ‐CAM Mechanism: σ Complexes as the Basis of σ‐Bond Metathesis at Late‐Transition‐Metal Centers

“…[68] In the monosilane dihydrogen complex [Ru(H) 2 (h 2 -H 2 )(h 2 -H-SiPh 3 )(PR 3 ) 2 ], no decoalescence was observed even at very low temperature. [50] In contrast, the two hydride ligands in [Ru(H)(H-SiMe 2 Cl)[P(h 3 -C 6 H 9 )Cy 2 ]-(PCy 3 )] are inequivalent as a result of the presence of two different phosphine ligands, and display two different J Si,H coupling constants (37 and 24 Hz). [43] …”

Nonclassical Ruthenium Silyl Dihydride Complexes TpRu(PPh3)(η3‐HSiR3H) [Tp = Hydridotris(pyrazolyl)borate]: Catalytic Hydrolytic Oxidation of Organosilanes to Silanols with TpRu(PPh3)(η3‐HSiR3H)

“…[1] The complex RuH 2 (η 2 -H 2 )(η 2 -HSiPh 3 )-(PCy 3 ) 2 (Cy = cyclohexyl), originally formulated as a dihydrogen σ-silane complex, in fact contains the [H 2 SiPh 3 ] moiety where the Si atom is almost symmetrically bonded to two hydrogen atoms with the two Si-H bond lengths measuring 1.72 and 1.83 Å. [2] Nikonov and co-workers have recently provided evidence from X-ray and DFT studies for the existence of H···Si···H bonding in the complex resulting from silane activation on the CpFe(iPr 2 MeP)H moiety; the complex is most appropriately formulated as CpFe-(iPr 2 MeP)(η 3 -H 2 SiR 3 ) (Figure 1). [3] Figure 1.…”