Proximity enforced oxidative addition of a strong unpolar σ-Si–Si bond at rhodium(i)

Abstract

After the oxidative addition, the two Si atoms are still engaged in weak, non-covalent, London dispersion type interactions.

Different Reactivities of (5-Ph2P-Ace-6-)2MeSiH toward the Rhodium(I) Chlorides [(C2H4)2RhCl]2 and [(CO)2RhCl]2. Hirshfeld Atom Refinement of a Rh–H···Si Interaction

“…Furthermore, the Rh–Si bond reported for 1 is slightly longer than the Rh­(III)–Si distances of the silyl hydrides ( i Pr NNN)­Rh­(H)­SiHRPh (2.2301(8) Å, R = Ph; 2.2466(7) Å, R = H) and the phosphinodisilane [RhCl­{κ 3 ( P , Si , Si )-PhP­( o -C 6 H 4 CH 2 Si i Pr 2 ) 2 }] (2.293(2) Å) . The Rh­(I) complex 2 consists of a longer Rh–Si bond (2.3887(5) [2.3759(5)] Å), which is still in the range for a covalent bond ( vide infra ) …”

“…102 The Rh(I) complex 2 consists of a longer Rh−Si bond (2.3887(5) [2.3759(5)] Å), which is still in the range for a covalent bond (vide infra). 107 The results discussed for 1 are based on Hirshfeld atom refinement (HAR), and we present the first comparison of a standard HAR 86 for a transition-metal hydride to a novel NoSpherA2 HAR. 92 The standard HAR model (Figure 2, top left, HAR_standard) and the NoSpherA2 HAR model (Figure 2, top right, HAR_NoSpherA2) both include an anisotropic refinement of the hydrogen atom displacement parameters.…”

“…The electron density, ρ(r) bcp , at the Rh−Si bond critical points (bcp) of 0.65 e Å −3 (1) and 0.57 e Å −3 (2), the respective Laplacians of ∇ 2 ρ(r) = −1.9 e Å −5 (1) and −1.8 e Å −5 (2), and the total energy densities over ρ(r) bcp of −0.70 (1) and −0.48 (2) are indicative of predominantly covalent Rh−Si interactions and compare well to the Si−Rh−Si interactions observed in the Rh(III) complex (5-Ph 2 P-Ace-6-SiMe 2 ) 2 RhCl (Table S3). 107 The electron density at the Rh−H bcp of ρ(r) bcp = 1.04 e Å −3 along with the respective Laplacian ∇ 2 ρ(r) = 0.9 e Å −5 are indicative of a strong Rh−H polar-covalent interaction. A pure silyl hydride, the final step in an oxidative addition, can be ruled out by the observed acute Si−Rh−H angle.…”

Practical method for hydroxyl-group protection using strontium metal and readily available silyl chlorides

“…It is widely known that when chlorosilane is mixed with alkali metals, such as Li 18 or Na, 19 these metals act as reducing agents, thus producing disilane. Disilane can be also synthesized using metallic Sm, 20 a low-valent Ti reagent prepared from TiCl 4 with metallic Zn, 21 and metallic Mg. 22 Furthermore, an example of a metal exchange reaction between chlorosilane and Grignard reagent to generate silyl magnesium species has been reported.…”