This work reports the outcome of thermal grafting of 2-ethynylaniline, 3-ethynylaniline, and 4-ethynylaniline on a hydrogenated Si(100) surface. Using high-resolution XPS and AFM, it was found that the grafting of these compounds could be attributed to resonating structures that arise from the position of an electron-donating NH group and an electron-withdrawing acetylene group. For the ortho- and para-positioned acetylene group, surface reactions were observed to proceed predominantly via the acetylene to form a Si-C bond, whereas the meta-positioned acetylene group was found to have undergone nucleophilic grafting through the NH group onto the silicon surface to form a Si-N bond. Furthermore, a tert-butoxycarbonyl-protected derivative for a meta-positioned ethynylaniline was synthesized to exclusively force the reaction to react with the acetylene group and subsequent analysis confirmed that unprotected 3-ethynylaniline had indeed reacted through the nucleophilic NH group as hypothesized. Thus, for the first time, the interplay between resonance structures and their effects on silicon surface modifications were systematically catalogued.
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http://dx.doi.org/10.1002/chem.201802003 | DOI Listing |
Nat Commun
January 2025
State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Frontiers Science Center for New Organic Matter, Haihe Laboratory of Sustainable Chemical Transformations, Nankai University 94 Weijin Road, Tianjin, China.
The diverse utility of acyclic vinylsilanes has driven the interest in the synthesis of enantioenriched vinylsilanes bearing a Si-stereogenic center. However, the predominant approaches for catalytic asymmetric generation of Si-stereogenic vinylsilanes have mainly relied on transition metal-catalyzed reactions of alkynes with different silicon sources. Here we successfully realize the enantioselective synthesis of linear silicon-stereogenic vinylsilanes with good yields and enantiomeric ratios from simple alkenes under rhodium catalysis.
View Article and Find Full Text PDFOrganometallics
January 2025
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K.
The group 1 alumanyls, [{SiN}AlM] (M = K, Rb, Cs; SiN = {CHSiMeNDipp}), display a variable kinetic facility (K < Rb < Cs) toward oxidative addition of the acidic C-H bond of terminal alkynes to provide the corresponding alkali metal hydrido(alkynyl)aluminate derivatives. Theoretical analysis of the formation of these compounds through density functional theory (DFT) calculations implies that the experimentally observed changes in reaction rate are a consequence of the variable stability of the [{SiN}AlM] dimers, the integrity of which reflects the ability of M to maintain the polyhapto group 1-arene interactions necessary for dimer propagation. These observations highlight that such "on-dimer" reactivity takes place sequentially and also that the ability of each constituent Al(I) center to effect the activation of the organic substrate is kinetically differentiated.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Engineering Research Center of Organosilicon Compounds & Materials (Ministry of Education), Hubei Key Lab on Organic and Polymeric OptoElectronic Materials, College of Chemistry and Molecular Sciences, and TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan 430072, China.
A modular platform technology for the synthesis of α-aryl carbonyl derivatives via Borono-Catellani-type secondary alkylation of arenes is presented. This practical method features a broad substrate scope regarding aryl boronic acid catechol esters, secondary alkyl bromides, and diversified terminating reagents (e.g.
View Article and Find Full Text PDFChemistry
January 2025
Université de Montréal, FRQNT Centre in Green Chemistry and Catalysis, Centre for Continuous Flow Synthesis, Department of Chemistry, 1375 av. Thérèse Lavoie-Roux, Montréal, QC, H2V 0B3, Canada.
The pentafluorosulfanyl (SF-) group has been the subject of a surge of interest in the past decade, but there is still little practicality associated with its synthesis and installation. Herein is reported the first continuous flow synthesis of pentafluorosulfanyl chloride (SFCl), the most common reagent for the synthesis of SF-substituted compounds. The synthesis is based on inexpensive and easy-to-handle reagents: sulfur powder (S), trichloroisocyanuric acid (TCCA) and potassium fluoride (KF).
View Article and Find Full Text PDFActa Neurobiol Exp (Wars)
January 2025
Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Piperine is an amide alkaloid isolated from the black pepper plant. This study examined the pain‑relieving activity of piperine against paclitaxel (PTX)‑induced neuropathy. Male mice were divided into 6 groups: Sham‑operated group (remained intact), PTX group (PTX‑treated mice receiving normal saline), PTX+ piperine 10, 25, and 50 mg/kg groups (PTX‑treated mice receiving piperine) and positive control group (PTX‑treated mice receiving imipramine 10 mg/kg).
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