Structural and bonding characteristics in transition metal–silane complexes

Abstract

Transition metal-silane complexes containing metal-eta 2-H-Si coordination display different structural and bonding characteristics in comparison to other sigma-complexes, such as dihydrogen and alkane (agostic) complexes. The different characteristics can be related to the strong sigma*-accepting properties of the eta 2-silane ligand(s) because of the weaker H-Si sigma bond. Various examples of metal-silane complexes have been reviewed and their structural stabilities have been systematically discussed. Silyl-hydride complexes having substantial silyl-hydrido interactions have also been emphasized.

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

“…Complexes with h 2 -SiÀH bonds have been reviewed by Corey and Braddock-Wilking, [28] by Lin, [29] and also by Nikonov; [30] another very recent review by Lachaize and Sabo-Etienne concentrates on ruthenium silane complexes. [31] Silane complexes formed the first class of s complexes to be discovered: Hoyano, Elder, and Graham reported the structure of [Re 2 (CO) 8 (m-h 2 ,h 2 -H 2 -SiPh 2 )] in 1969.…”

“…In monosilane chemistry, the chlorosilane complex [RuH(h 2 -HSiMe 2 Cl){(h 3 -C 6 H 8 )PCy 2 }(PCy 3 )] is the best representative example. [43] A 1D HMQC 29 Si-1 H{ 31 P} experiment shows two doublets in the high-field region with J Si,H values of 37.3 and 24.1 Hz assigned to the s-H À Si and the hydride ligands, respectively. The s-H À Si bond length is 1.91(2) by X-ray diffraction (1.891 by DFT/B3LYP calculations) whereas the secondary interaction between the hydride ligand and the silicon atom is characterized by a separation of 1.99(2) by X-ray diffraction (2.076 by DFT/B3LYP calculations).…”

Unique {H(SiR3)2}, (H2SiR3), H(HSiR3), and (H2)SiR3Ligand Sets Supported by the {Fe(Cp)(L)} Platform (L=CO, PR3)

“…[1] Among different X À Y bond rupture/formation reactions the activation of H À H, [2] H À C, [3] and H À Si [4,5] bonds have received most theoretical treatment due to their relevance to a range of important catalytic reactions, such as hydrogenation, alkane functionalization, hydrosilation, and so forth, [1] and due to the simplicity of hydride as a 1s electron ligand. [2] While earlier work has been focused primarily on theoretical rationalization of metal-ligand bonding in the starting and final compounds, current research shifts more towards the understanding of the reaction mechanisms, which to a great extent deals with elucidating the nature of interligand interactions in reactive intermediates and transition states.…”

Strength of Si–H ⋯ B charge-inverted hydrogen bonds in 1-silacyclopent-2-enes and 1-silacyclohex-2-enes

“…Bonding properties of the Si-H· · · Y bridge are well known [5][6][7][8][9]. For example, in case of Y being a transition metal, this interaction is called an agostic bond [10][11][12][13] or a σ interaction [12][13][14][15][16][17] depending on a specific situation, whereas if Y is an electron-deficient element (as, for example, boron), this type of interaction was called a "charge-inverted hydrogen bond" (CIHB) [11][12][13][18][19][20][21][22][23][24][25].…”