Simple two-coordinate acyclic silylenes, SiR(2), have hitherto been identified only as transient intermediates or thermally labile species. By making use of the strong σ-donor properties and high steric loading of the B(NDippCH)(2) substituent (Dipp = 2,6-(i)Pr(2)C(6)H(3)), an isolable monomeric species, Si{B(NDippCH)(2)}{N(SiMe(3))Dipp}, can be synthesized which is stable in the solid state up to 130 °C. This silylene species undergoes facile oxidative addition reactions with dihydrogen (at sub-ambient temperatures) and with alkyl C-H bonds, consistent with a low singlet-triplet gap (103.9 kJ mol(-1)), thus demonstrating fundamental modes of reactivity more characteristic of transition metal systems.
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http://dx.doi.org/10.1021/ja301042u | DOI Listing |
Chemistry
June 2021
Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton, Alberta, T6G 2G2, Canada.
The synthesis of the new bulky vinyllithium reagent ( IPr=CH)Li, ( IPr=[(MeCNDipp) C]; Dipp=2,6-iPr C H ) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π-electron donor ligand [ IPr=CH] . Furthermore, a high-yielding route to the degradation-resistant Si precursor IPr⋅SiBr is presented.
View Article and Find Full Text PDFJ Am Chem Soc
January 2021
Institut für Anorganische Chemie, Universität Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany.
Isolation of two-coordinate compounds of heavier Group 15 elements in low oxidation state is challenging due to the preferential formation of dimers or oligomers. Herein, we report the first examples of donor-stabilized two-coordinate Sb(I) and Bi(I) ions. The reduction of antimony and bismuth trihalides with KC in the presence of cyclic alkyl(amino) carbene (cAAC) afforded Sb(I) and Bi(I) cations in the form of triflate salts [(cAAC)Sb][OTf] () and [(cAAC)Bi][OTf] ().
View Article and Find Full Text PDFIn recent decades, the chemistry of stable silylenes (RSi:) has evolved significantly. The first major development in this chemistry was the isolation of a silicocene which is stabilized by the Cp* (Cp* = η-CMe) ligand in 1986 and subsequently the isolation of a first -heterocyclic silylene (NHSi:) in 1994. Since the groundbreaking discoveries, a large number of isolable cyclic silylenes and higher coordinated silylenes, i.
View Article and Find Full Text PDFDalton Trans
June 2020
Department of Chemistry, WACKER-Institute of Silicon Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstraße 4, 85748 Garching bei München, Germany.
Due to their outstanding reactivity, acyclic silylenes have emerged as attractive organosilicon alternatives for transition metal complexes on the way to metal-free catalysis. However, exploration of their reactivity is still in its infancy, as only a few derivatives of this unique compound class have been isolated so far. Here, we present the results of an extensive reactivity investigation of the previously reported acyclic iminosiloxysilylene 1.
View Article and Find Full Text PDFChem Sci
July 2019
Department of Chemistry , University of Alberta, 11227 Saskatchewan Drive , Edmonton , Alberta , Canada T6G 2G2 . Email:
The facile synthesis of a rare two-coordinate acyclic silylene (RSi:) that is stabilized using a bulky vinylic -heterocyclic olefin ligand and the strongly σ-donating hypersilyl group [Si(SiMe)] is reported. This vinyl-substituted silylene exhibits an excellent combination of prolonged thermal stability along with high reactivity towards small molecules. Despite being stable for months in solution, the reactivity of this new silylene is manifest in its ambient temperature activation of strong B-H, Si-Cl, C-O, P-P and C-H bonds.
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