Synthesis and reactivity of silicon transition metal complexes. Part 27. Metallotrihydridosilanes of molybdenum and tungsten: synthesis, characterization, and vibrational studies of (C5R5)(OC)2(Me3P)M-SiH3 (M = Mo, W; R = H, Me)

Abstract

with n-butyllithium, react with HSiCl3 (5) to give C5R5(OC)2(Me3P)M-Si(H)Cl2 (6a-c). Compound 6b is additionally obtained, starting with the tetramethylphosphonium metálate [MeiPlCWfCOMPMeslCsHs] (4), generated from lb with the ylide MesP=CH2 (3). On treatment with L1AIH4, 6a-c undergo smooth Cl/H exchange at the silicon to afford the metallotrihydridosilanes CsRslOCMMesPIM-SiHs (7a-c). The spectroscopic properties of all the compounds have been extensively studied by NMR and IR spectroscopy. In the case of 7a-c, detailed studies of the Raman spectra have been performed as well as force field calculations for the M-S1H3 units, yielding valuable information with respect to Si-H and -Si force constants.

The Pentamethylcyclopentadienylsilicon(II) Cation: Synthesis, Characterization, and Reactivity

“…The fluxional structure of the η 3 ‐Cp*Si unit in solution is documented by NMR spectroscopy. As expected, the FeSi bond in the silicon(II) compound 13 is longer (2.3677(6) Å) than that in the silicon(IV) compound H 3 SiFe(CO) 2 Cp* (2.287(2) Å) 85. According to theoretical calculations, the electron density of the FeSi bond in 13 is mainly located at iron (74.2 %) and less at silicon (25.8 %).…”

Ruthenium Silyl Complexes Containing the Cp(PMe3)2Ru Moiety: Preparation, Substituent Effects, and Silylene Character in the Ru−Si Bond

“…The substituent effects on the chemical shifts of the NMR active nuclei in complexes 1-10 can be grouped into three classes: silicon, nuclei attached to silicon, and nuclei two or more bonds from silicon. The resonances for the silyl group in the 29 Si NMR spectra of complexes 1-10 were observed over a 160 ppm range (Table 1). A plot of δ( 29 Si) as a function of ∑χ i for complexes 1-10 is shown in Figure 3.…”

“…The other set could be based on the number of methyl groups on silicon to give a dimethylsilyl class, a monomethylsilyl class, and a "non-methylsilyl" class. The ability to use different criteria to classify the silyl groups probably explains why 1 H and 13 C chemical shift changes are so well behaved compared to 29 Si chemical shift changes upon H/Cl, H/Me, and Cl/Me exchanges (see text). All substituent exchanges can be viewed as conversions within a silyl class just by changing the classification criteria.…”

“…Malisch and co-workers successfully prepared a wide variety of late transition metal silyl complexes of the type L n MSiX 3 (ML n = CpCr(CO) 3 , CpMo(CO) 3 , Cp*Mo(CO) 3 , CpMo(CO) 2 (PMe 3 ), Cp*Mo(CO) 2 (PMe 3 ), CpW(CO) 3 , Cp*W(CO) 3 , CpW(CO) 2 (PMe 3 ), Cp*W(CO) 2 (PMe 3 ), CpFe(CO) 2 , Cp*Fe(CO) 2 , CpRu(CO) 2 , Cp*Ru(CO) 2 ; SiX 3 = SiHCl 2 , SiHMeCl, SiHMe 2 , SiPhHCl, SiPh 2 H, etc.) by reacting metal anions with the corresponding chlorosilane in hydrocarbon solvent. − Controlled exchange reactions at silicon afforded a variety of metallohydrosilanes, − -fluorosilanes, -aminosilanes, , -silanols, ,− and -alkoxysilanes…”

“…by reacting metal anions with the corresponding chlorosilane in hydrocarbon solvent. [25][26][27][28][29][30] Controlled exchange reactions at silicon afforded a variety of metallohydrosilanes, [27][28][29][30] -fluorosilanes, 31 -aminosilanes, 32,33 -silanols, 28,34-37 and -alkoxysilanes. 13 Herein, we describe the formation of chlorosilyl ruthenium complexes Cp(PMe 3 ) 2 RuSiR 2 Cl employing a little-used HCl elimination reaction between an electronrich ruthenium hydride Cp(PMe 3 ) 2 RuH and the corresponding chlorosilanes; the formation of some of these chlorosilyl ruthenium complexes has been previously communicated.…”