Cleavage of the C-Si bond in Trifluoro(phenyl)silane with Aliphatic Alcohols

Abstract

Trifluoro(phenyl)silane reacts with aliphatic alcohols under reflux. The reaction involves not only Si!F bond cleavage to form ethoxyfluoro(phenyl)silanes, but also C!Si bond cleavage to form benzene and alkoxyfluoro-and tetraalkoxysilanes. The formation of the latter products was proved by 19 F and 29 Si NMR spectroscopy and also by model disproportionation reactions of trifluoro(phenyl)silane with trimethoxy-(phenyl)-, tetramethoxy-, or tetraethoxysilanes.It has long been believed that alcoholysis of trifluoro(phenyl)silane involves no other processes than Si3F bond cleavage. Thus, as shown in [1], the reaction of trifluoro(phenyl)silane with ethanol results in exclusive formation of diethoxy(phenyl)silane, whereas the third fluorine atom remains completely intact.The potentiometric titration curve of trifluoro-(phenyl)silane in DMSO with 0.

Synthesis of Iron Hydrides by Selective C–F/C–H Bond Activation in Fluoroarylimines and Their Applications in Catalytic Reduction Reactions

“…To determine the destination of the fluorine atom in the three-component reaction, Fe(PMe 3 ) 4 , 4, HSi(OEt) 3 , and solvent were sealed in an NMR tube, and the reaction was monitored after 24 h. In the 19 F NMR spectrum of this reaction solution, a singlet at δ = -153.7 ppm could be identified as the signal of (CH 3 CH 2 O) 3 SiF. [17] The 19 F NMR signal of 9 appears at δ = -114.8 ppm. The relative integral ratio of these two signals is ca.…”

Synthesis of Methanol and Diols from CO2 via Cyclic Carbonates under Metal-Free, Ambient Pressure, and Solvent-Free Conditions

“…The corresponding 19 F NMR spectrum (see Figure S8) possesses a peak at approximately −140 ppm, which has previously been attributed to a SiF 2 -type compound. 47 Finally, a singlet peak is observed at −35 ppm in the 29 Si NMR spectrum which is close in value to PhSiH(OEt) 2 48 and a related species could possibly form following elimination of the F atom in structure (c). The GC-MS trace of the reaction mixture prior to hydrolysis shows the presence of tris(methoxy)phenylsilane, indicating that some MeOH is formed prior to hydrolysis due to the moisture content in the catalyst (see above) and that the MeOH can exchange with the substituents attached to the Si-center.…”

“…These peaks may be tentatively attributed to PhSi­(OMe) 2 F-type species related to intermediate ( d ) in Scheme . , A triplet was also observed at −109.16 ppm, with a J-coupling of 206 Hzthis value is typical of a SiF 2 species, indicating that a catalytic intermediate with two F atoms is also present. The corresponding 19 F NMR spectrum (see Figure S8) possesses a peak at approximately −140 ppm, which has previously been attributed to a SiF 2 -type compound . Finally, a singlet peak is observed at −35 ppm in the 29 Si NMR spectrum which is close in value to PhSiH­(OEt) 2 and a related species could possibly form following elimination of the F atom in structure ( c ).…”

“…These peaks may be tentatively attributed to PhSi(OMe) 2 Ftype species related to intermediate (d) in Scheme 3. 45,46 A triplet was also observed at −109.16 ppm, with a J-coupling of 206 Hzthis value is typical of a SiF 2 species, 47 indicating that a catalytic intermediate with two F atoms is also present. The corresponding 19 F NMR spectrum (see Figure S8) possesses a peak at approximately −140 ppm, which has previously been attributed to a SiF 2 -type compound.…”

Sol-Gel-Synthesis of Nanoscopic Complex Metal Fluorides

“…The small signals between −150 and −156 ppm are related to alkoxyfluorosilanes (RO) 4− x -SiF x (R = Me, Et). [40] The crystal structure of Ca 2 AlF 7 has five distinct fluorine sites. One fluorine site is connected to three calcium F-Ca(3) and four fluorine sites are connected to aluminum and calcium with varying numbers of calcium Al-F-Ca(n) [33].…”