Tris(pentafluoroethyl)silane, which is conveniently accessible by the treatment of Si(C F ) X (X=Cl, Br) with Bu SnH, was successfully employed for hydrosilylation reactions. In the presence of a palladium catalyst, hydrosilylation of phenylacetylene with Si(C F ) H affords the product of an α-addition whereas the reaction of trimethylsilylacetylene with the silane leads to the β-trans product. Tris(pentafluoroethyl)silane can be deprotonated by sterically demanding bases such as lithium diisopropylamide at low temperatures to give the corresponding silanide ion. The addition of crown ethers or cryptands to this highly reactive species enabled the isolation and characterization of salt-like tris(pentafluoroethyl)silanide at room temperature.
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http://dx.doi.org/10.1002/anie.201609096 | DOI Listing |
Angew Chem Int Ed Engl
April 2022
Universität Bielefeld, Fakultät für Chemie, Centrum für Molekulare Materialien, Universitätsstraße 25, 33615, Bielefeld, Germany.
Compounds exhibiting main group elements in low oxidation states were found to mimic the reactivity of transition metal complexes. Like the latter, such main group species show a proclivity of changing their oxidation state as well as their coordination number by +2, therefore fulfilling the requirements for oxidative additions. Prominent examples of such main group compounds that undergo oxidative additions with organohalides R-X (R=alkyl, aryl, X=F, Cl, Br, I) are carbenes and their higher congeners.
View Article and Find Full Text PDFChemistry
August 2021
Universität Bielefeld, Fakultät für Chemie, Centrum für Molekulare Materialien, Universitätsstraße 25, 33615, Bielefeld, Germany.
While alkyl-substituted siloxanes are widely known, virtually nothing is known about perfluoroalkyl siloxanes and their congener species, the silanols and silanolates. We recently reported on the tris(pentafluoroethyl)silanide ion, [Si(C F ) ] , which features Lewis amphoteric character deriving from the pentafluoroethyl substituents and their strong electron-withdrawing properties. Transferring this knowledge, we investigated the Lewis amphoteric behavior of the tris(pentafluoroethyl)silanolate, [Si(C F ) O] .
View Article and Find Full Text PDFAngew Chem Int Ed Engl
May 2021
Universität Bielefeld, Fakultät für Chemie, Centrum für Molekulare Materialien, Universitätsstrasse 25, 33615, Bielefeld, Germany.
According to a first view on the geometrical and electronic structure of the tris(pentafluoroethyl)silanide, this anion appears as a Lewis base. Quantum chemical calculations on perfluoroalkylated silanides show significantly lower HOMO and LUMO energy levels in comparison to their non-fluorinated counterparts, which implies reduced Lewis basicity and increased Lewis acidity of the [Si(C F ) ] ion. With these findings and a HOMO-LUMO gap of 4.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2016
Universität Bielefeld, Fakultät für Chemie, Centrum für Molekulare Materialien, Universitätsstrasse 25, 33615, Bielefeld, Germany.
Tris(pentafluoroethyl)silane, which is conveniently accessible by the treatment of Si(C F ) X (X=Cl, Br) with Bu SnH, was successfully employed for hydrosilylation reactions. In the presence of a palladium catalyst, hydrosilylation of phenylacetylene with Si(C F ) H affords the product of an α-addition whereas the reaction of trimethylsilylacetylene with the silane leads to the β-trans product. Tris(pentafluoroethyl)silane can be deprotonated by sterically demanding bases such as lithium diisopropylamide at low temperatures to give the corresponding silanide ion.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2016
Universität Bielefeld, Fakultät für Chemie, Centrum für Molekulare Materialien, Universitätsstrasse 25, 33615, Bielefeld, Germany.
The tris(pentafluoroethyl)silanide anion is accessible by the deprotonation of Si(C F ) H at low temperatures. Subsequent quenching of the resulting salt-like compounds with suitable electrophiles, such as transition-metal complexes or Group 14 element halides, leads to a plethora of novel tris(pentafluoroethyl)silane derivatives. This underlines the versatility of Li[Si(C F ) ] as a powerful nucleophilic transfer reagent.
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