54128-17-5Relevant academic research and scientific papers
Acidity, basicity, and the stability of hydrogen bonds: Complexes of RO- + HCF3
Chabinyc, Michael L.,Brauman, John I.
, p. 10863 - 10870 (2007/10/03)
Ion-molecule complexes of RO- (R = Me, Et, i-Pr) and HCF3 have been studied with Fourier transform ion cyclotron resonance spectrometry. The RO- complexation energies with HCF3 were measured relative to RO-·H2O. These complexes, [ROHCF3]-, have complexation energies on the order of -20 kcal/tool and have low deuterium fractionation factors and are, therefore, hydrogen bonded. The structure of the complexes was studied by isotopic equilibrium experiments and ab initio calculations. All of the complexes studied have the structure RO-·HCF3 even when HCF3 is a stronger acid than ROH. The structure of the complexes can be understood through electrostatic arguments rather than the difference in acidity between the ion and neutral.
Gas-phase ionic reactions of benzyl and methoxide anions
Gatev, Geo G.,Zhong, Meili,Brauman, John I.
, p. 531 - 536 (2007/10/03)
Gas-phase reactions of benzyl and methoxide anions with alkyl formate and other esters were compared using Fourier transform io cyclotron resonance spectroscopy. Although these anions have similar basicities, in many cases the reaction pathways differ.
Electron transfer as a possible initial step in nucleophilic addition elimination reactions between (radical) anions and carbonyl compounds in the gas phase
Staneke, Paul O.,Ingemann, Steen,Nibbering, Nico M. M.
, p. 179 - 184 (2007/10/03)
The reactions of the HO-, CH3S-, CH2S- and CH2=C(CH3)-CH2- ions with three ketones (CF3COR; R=CH3, CF3, C6H5) and three esters of trifluoroacetic acid (CF3CO2R; R=CH3, C2H5 and C6H5) have been studied with use of Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry. All four negative ions react exclusively by proton transfer with CF3COCH3. With the other substrates, the HO- ion reacts by various pathways, such as proton transfer, SN2 substitution, E2 elimination and attack on the carbonyl group. The CH3S- ion is unreactive towards CF3COC6H5 but is able to react by hydride transfer, SN2, E2 and/or carbonyl attack with the remaining neutral species. The CH2S- radical anion reacts by electron transfer to afford stable molecular radical anions of CF3COCF3 and CF3COC6H5, whereas the main reaction with the two esters, CF3CO2CH3 and CF3CO2C2H5, is dissociative electron transfer leading to CF3CO2- and CF3- ions. The CH2=C(CH3)-CH2- anion displays a more complex reactivity pattern involving electron transfer, SN2, E2 as well as attack on the carbonyl group. Direct evidence for the occurrence of electron transfer as the initial step in an overall BAC2 type process has not been obtained for the systems studied. The reaction of the CH2S- ion with CF3CO2C6H5 was observed, however, to yield exclusively a CF3COCHS-. radical anion. Based upon the absence of a BAC2 process in the reaction of CH2S- with the methyl and ethyl esters of trifluoroacetic acid in combination with the facile occurrence of electron transfer from this radical anion, it is suggested that the CF3COCHS-. ion is formed by an initial electron transfer followed by coupling between the CH2S molecule and the CF3CO2C6H5- radical anion and subsequent loss of C6H5OH from the collision complex.
Gas-phase reactions of oxide and superoxide anions with CF4, CF3Cl, CF3Br, CF3I, and C2F4 at 298 and 500 K
Morris, Robert A.
, p. 2372 - 2381 (2007/10/02)
Rate constants and product branching fractions have been measured for the gas-phase reactions of oxide (O-) and superoxide (O2-) anions with the halocarbons CF4, CF3Cl, CF3Br, CF3I, and C2F4 using a variable temperature-selected ion flow tube (VT-SIFT) instrument operated at 298 and 500 K.The reactions of O- with CF3X (X = Cl, Br, I) are fast and produce F-, XF-, and XO- for all X.For CF3Cl and CF3Br, X- is also formed.For CF3I, CF3- and IOF- are minor products.O- reacts rapidly with C2F4 producing F- as the major ionic product, along with contributions from reactive detachment and minor formation of FCO-, CF3-, and C2F3O-.The reaction of O2- with CF3Cl is slow, and both clustering and X- formation were observed.For CF3Br and CF3I, the reactions with O2- are fast, and nondissociative charge transfer was observed in addition to X- formation.O2- reacts rapidly with C2F4 by reactive detachment, in addition to producing F- as the major ionic product with smaller amounts of F2-, FCO-, FCO2-, CF3O-, and C2F4O-.O- and O2- were both found to be unreactive with CF4 at 298 and 500 K.The efficiencies of the reactions of both O- and O2- with CF3X are greater for the heavier halides at both 298 and 500 K.The rate constants for the reactions of O2- with CF3X appear to correlate both with the rates of thermal electron attachment to CF3X and with the electron affinities of CF3X, indicating that the O2- + CF3X reaction mechanism may involve initial electron transfer followed by dissociation.Thus the negative electron affinity of CF3Cl may explain the very slow rate for reaction with O2- despite the available exothermic pathways.
Product Branching in Infrared Multiple Photon Decomposition of Gas-Phase Ions. Mechanistic Implications for Proton-Transfer Reactions
Moylan, Christopher R.,Jasinski, Joseph M.,Brauman, John I.
, p. 1934 - 1940 (2007/10/02)
Negative ions that lie on potential surfaces for proton-transfer reactions have been photolyzed in the gas phase with an infrared laser.The relative photodissociation yields of reactants and products of the proton-transfer reactions as well as the kinetics of the reactions themselves have been measured.The results provide details about the potential surfaces, mechanisms. and theoretical theromochemistry of these reactions.
