127808-36-0Relevant articles and documents
Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid
Driess, Matthias,Hermannsdorfer, André
supporting information, p. 13656 - 13660 (2021/05/03)
A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf)4, is reported, acting as the first neutral silicon-based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf)4 leads to [L2Si(OTf)4] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si?OTf bonds. In contrast, it can cleave C?X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf)4 allows a gentle oxydefluorination of mono- and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf)6] dianion.
Reactions of methyl(phenyl)silylene with CO and PH3-the formation of acid-base complexes
Bornemann, Holger,Sander, Wolfram
, p. 156 - 164 (2007/10/03)
The thermal reaction of methyl(phenyl)silylene 1a with CO and PH3, respectively, was investigated using matrix isolation spectroscopy in combination with DFT calculations. The silylene 1a was produced by UV irradiation (λ>400 nm followed by λ>3
Oxidation of methyl(phenyl)silylene - Synthesis of a dioxasilirane
Bornemann, Holger,Sander, Wolfram
, p. 6727 - 6734 (2007/10/03)
The oxidation of methyl(phenyl)silylene, 3f, with molecular oxygen is investigated using matrix isolation spectroscopy in combination with DFT calculations. The UV irradiation (λ > 305 nm) of phenylsilyldiazomethane, 8, matrix-isolated in argon at 10 K, p
Synthesis and characterization of sterically hindered diarylsilanes containing 2,4,6-trimethylphenyl and 2,4,6-tris( trifluoromethyl) phenyl substituents. X-ray crystal structure of bisfluorosilane
Braddock-Wilking, Janet,Schieser, Matt,Brammer, Lee,Huhmann, Jean,Shaltout, Raef
, p. 89 - 98 (2007/10/02)
Sterically hindered diarylsilanes have been prepared by two synthetic routes.Dimesitylsilane, Mes2SiH2 (1), (Mes = 2,4,6- trimethylphenyl) was synthesized by reaction of mesityl magnesium bromide with HSiCl3 followed by reduction with LiAlH4, or by reaction of mesityl magnesium bromide with (TfO)2SiH2.The mixed diaryl system, MesPhSiH2 (2), was prepared by reaction of (TfO)PhSiH2, with one equivalent of MesMgBr.Diarylsilanes containing the 2,4,6-tris(trifluoromethyl)phenyl substituent, RF, were prepared by reaction of HSiCl3 with 2 equivalents of RFLi to give (RF)2SiHF (3) through a Cl/F halogen exchange.Reduction of 3 with LiAlH4 afforded (RF)2SiH2 (4) which can also be prepared from RFLi and (TfO)2SiH2.All compounds have been characterized by multinuclear NMR, IR, mass spectrometry and chemical analyses.An X-ray crystallographic study of 3 shows that the immediate geometry about silicon is approximately tetrahedral with a C-Si-C angle of 115.8(1)deg.There are unusual intramolecular interactions in 3 with four short Si . . .F contacts with the ortho-CF3 substituents on the aromatic ring which results in an overall tetracapped tetrahedral geometry about silicon.Crystal data for 3 are as follows: monoclinic, P21/c, with a = 9.827(2) Angstroem, b =15.938(3) Angstroem, c =13.239(3) Angstroem, V = 2072.6(8) Angstroem3, Z = 4; and R = 0.0492 (Rw = 0.0535).The short intramolecular Si . . .F contacts are observed in solution for both 3 and 4 by 29Si NMR spectroscopy.Keywords: Silicon; Group 14; Aryl; Mesityl; Crystal structure; Hindered (bulky) ligands
Preparation of New Monomeric, Oligomeric, and Polymeric Silyl Triflates
Uhlig, Wolfram
, p. 47 - 54 (2007/10/02)
The highly reactive silyl triflates R3SiOSO2CF3 are valuable reagents in organosilicon chemistry.New triflate derivatives of mono- and oligosilanes have been prepared by substitution of phenyl groups or hydrogen atoms for the trifluoromethanesulfonyl group.The presence of the electron-withdrawing triflate group leads to a strong deactivation of the other substituents at the silicon atom, and the displacement of a second phenyl group at the same silicon atom is much slower than the first step.For this reason in the case of phenylated oligosilanes stepwisemonosubstitution of the silicon atoms has been found.Other new oligomeric silyl triflates are obtained by reaction of silanediyl(triyl) bis(tris)(trifluoromethanesulfonates) with lithium derivatives of organosilicon compounds.Finally, the cleavage of silicon - phenyl bonds of poly by CF3SO3H leads to triflate derivatives of polysilanes. Key Words: Silyl triflates / Organosilanes
Neuartige Silyltriflat-Derivate
Uhlig, Wolfram,Tzschach, Alfred
, p. C1 - C5 (2007/10/02)
The selective cleavage of phenylsilanes by triflic acid gives novel silyltriflates.Unique, substituted derivates have been synthesized by alkylation with organometallic reagents.Triflate derivatives of oligo- and cyclo-silanes are similarly formed.
