20583-04-4Relevant articles and documents
Rapid and easy access to (E)-1,3-enynes, 1,3-diynes and allenes starting from propargylic acetals, exploiting the different reactivity of lithium and mixed lithium-potassium organometallic reagents
Blangetti, Marco,Deagostino, Annamaria,Rosso, Helena,Prandi, Cristina,Zavattaro, Chiara,Venturello, Paolo
, p. 5867 - 5874 (2007)
The treatment of propargylic acetals with various lithium and mixed lithium-potassium Schlosser reagents, has allowed a one-pot synthesis of (E)-1,3-enynes, 1,3-diynes and allenes, depending on the reaction conditions and the selected base. Various reacti
Mechanosynthesis of Odd-Numbered Tetraaryl[n]cumulenes
Ardila-Fierro, Karen J.,Bolm, Carsten,Hernández, José G.
, p. 12945 - 12949 (2019/08/01)
A mechanochemical synthesis of one-dimensional carbon allotrope carbyne model compounds, namely tetraaryl[n]cumulenes (n=3, 5) was realized. Central for the mechanosynthesis of the cumulenic carbon nanostructures were the development of a mechanochemical Favorskii alkynylation-type reaction and the implementation of a solvent-free, acid-free reductive elimination with tin(II) chloride by ball milling.
A Mechanistic Study of Halogen Addition and Photoelimination from π-Conjugated Tellurophenes
Carrera, Elisa I.,Lanterna, Anabel E.,Lough, Alan J.,Scaiano, Juan C.,Seferos, Dwight S.
supporting information, p. 2678 - 2689 (2016/03/12)
The ability to drive reactivity using visible light is of importance for many disciplines of chemistry and has significant implications for sustainable chemistry. Identifying photochemically active compounds and understanding photochemical mechanisms is important for the development of useful materials for synthesis and catalysis. Here we report a series of photoactive diphenyltellurophene compounds bearing electron-withdrawing and electron-donating substituents synthesized by alkyne coupling/ring closing or palladium-catalyzed ipso-arylation chemistry. The redox chemistry of these compounds was studied with respect to oxidative addition and photoelimination of bromine, which is of importance for energy storage reactions involving X2. The oxidative addition reaction mechanism was studied using density functional theory, the results of which support a three-step mechanism involving the formation of an initial η1 association complex, a monobrominated intermediate, and finally the dibrominated product. All of the tellurophene derivatives undergo photoreduction using 430, 447, or 617 nm light depending on the absorption properties of the compound. Compounds bearing electron-withdrawing substituents have the highest photochemical quantum efficiencies in the presence of an alkene trap, with efficiencies of up to 42.4% for a pentafluorophenyl-functionalized tellurophene. The photoelimination reaction was studied in detail through bromine trapping experiments and laser flash photolysis, and a mechanism is proposed. The photoreaction, which occurs by release of bromine radicals, is competitive with intersystem crossing to the triplet state of the brominated species, as evidenced by the formation of singlet oxygen. These findings should be useful for the design of new photochemically active compounds supported by main-group elements.
A new tetraarylcyclopentadienone based low molecular weight gelator: Synthesis, self-assembly properties and anion recognition
Boiani, Mattia,Baschieri, Andrea,Cesari, Cristiana,Mazzoni, Rita,Stagni, Stefano,Zacchini, Stefano,Sambri, Letizia
body text, p. 1469 - 1478 (2012/07/31)
A new class of tetraarylcyclopentadienones bearing 3-hydroxy-1-propynyl substituents has been synthesized. One of them, 3,4-bis (4-(3-hydroxy-3- methylbut-1-ynyl) phenyl)-2,5-diphenylcyclopenta-2,4-dienone, exhibits pronounced aggregation properties in various organic solvents responding to thermal and ultrasound stimuli and represents the first example of a tetraarylcyclopentadienone based low molecular weight organogelator. The hydroxydimethyl group on the ethynyl substituent proved to be essential to perform the gelation process. The 1H NMR analysis and FT-IR spectroscopy suggested that the intermolecular π-π and hydrogen bonding interactions of the gelator with the solvent are the main driving forces for the supramolecular assembly. The SEM images of xerogels show the characteristic gelation morphologies of 3D fibrous network structures. Fluorescence and UV/Vis absorption studies provided more information to define the molecular packing model in the gelation state. In addition the obtained gels show selective response to the fluoride anion. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2012.
