18751-09-2Relevant academic research and scientific papers
Olefin isomerization and hydrosilylation catalysis by lewis acidic organofluorophosphonium salts
Perez, Manuel,Hounjet, Lindsay J.,Caputo, Christopher B.,Dobrovetsky, Roman,Stephan, Douglas W.
, p. 18308 - 18310 (2013)
Organofluorophosphonium salts of the formula [(C6F 5)3-xPhxPF][B(C6F5) 4] (x = 0, 1) exhibit Lewis acidity derived from a low-lying σ* orbital at P opposite F. This acidity is evidenced by the reactions of these salts with olefins, which catalyze the rapid isomerization of 1-hexene to 2-hexene, the cationic polymerization of isobutylene, and the Friedel-Crafts-type dimerization of 1,1-diphenylethylene. In the presence of hydrosilanes, olefins and alkynes undergo efficient hydrosilylation catalysis to the alkylsilanes. Experimental and computational considerations of the mechanism are consistent with the sequential activation and 1,2-addition of hydrosilane across the unsaturated C-C bonds.
Well-defined NHC-rhodium hydroxide complexes as alkene hydrosilylation and dehydrogenative silylation catalysts
Truscott, Byron J.,Slawin, Alexandra M. Z.,Nolan, Steven P.
, p. 270 - 276 (2013/02/25)
Alkene hydrosilylation and dehydrogenative silylation reactions, mediated by [Rh(cod)(NHC)(OH)] complexes (cod = 1,5-cyclooctadiene; NHC = N-heterocyclic carbene) are described. The study details a comparison of the catalytic activity and steric characteristics of four rhodium complexes bearing different NHC ligands. The novel [Rh(cod)(Ii-PrMe)(OH)] complex (Ii-PrMe = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidine) was designed to improve the reactivity of Rh(i)-hydroxides and proved to be a successful promoter of hydrosilylation and dehydrogenative silylation, displaying good stereo- and regiocontrol. The Royal Society of Chemistry 2013.
High oxidation state rhodium and iridium bis(silyl)dihydride complexes supported by a chelating pyridyl-pyrrolide ligand
McBee, Jennifer L.,Escalada, Jose,Tilley, T. Don
scheme or table, p. 12703 - 12713 (2010/01/30)
New rhodium and iridium complexes containing the bidentate ligand 3,5-diphenyl-2-(2-pyridyl)pyrrolide (PyPyr) were prepared. The bis(ethylene) complex (PyPyr)Rh(C2H4)2 (3) reacted with HSiEt 3, HSiPh3, and HSitBuPh2 to produce the 16-electron Rh(V) bis(silyl)dihydrides (PyPyr)Rh(H)2(SiEt 3)2 (8), (PyPyr)Rh-(H)2(SiPh3) 2 (9), and (PyPyr)Rh(H)2(SitBuPh 2)2 (10), respectively. The analogous Ir(V) bis(silyl)dihyride (PyPyr)Ir(H)2(SiPh3)2 (11) has also been synthesized. X-ray crystallography reveals that 9-11 adopt a coordination geometry best described as a bicapped tetrahedron. Silane elimination from 9 and 10 occurred in the presence of either HSiEt3 or PPh3. Mechanistic studies of the silane exchange process involving 10 and free HSiEt3 (to give 8) indicate that this process occurs by rate-limiting reductive elimination of HSitBuPh2 from 10 to generate a 14-electron Rh(III) intermediate of the type (PyPyr)Rh(H)(Si tBuPh2).
