17032-46-1Relevant academic research and scientific papers
Channeling of products in the hot atom reaction H + (CN)2 → HCN/HNC + CN and in the reaction of CN with CH3SH
Decker, Brian K.,Macdonald, R. Glen
, p. 6817 - 6825 (2001)
Infrared transient absorption spectroscopy was used to determine the total product branching fractions for the gas-phase hot atom reaction H + (CN)2 → HCN/HNC + CN (a) and the reaction CN + CH3SH → HCN/HNC + CH3S/CH2SH (b) at 293 K. The reactive H atoms had an initial mean translational energy of 92 kJ mol-1, with a 38 kJ mol-1 fwhm Gaussian energy distribution. The branching fractions determined for the product channels forming HCN and HNC, respectively, are 0.88 and 0.12 (±0.05) for reaction (a) and 0.81 and 0.19 (±0.08) for reaction (b). The bimolecular rate constant for reaction (b) was measured to be (2.7 ± 0.3) × 10-10 cm3 molec-1 s-1 at 293 K. The observed product branching fractions for reaction (a) are consistent with the assumption that the average reactive cross sections for the two product channels are approximately equal above their respective energy thresholds. The results for reaction (a) are compared with the related H + XCN (X = Br, Cl) reactions. The large rate coefficient for reaction (b) suggests an interaction via a long-range intermolecular potential, which is facilitated by the small ionization energy of CH3SH and large electron affinity of CN. The results for reaction (b) are compared with the related reactions of Cl and OH with CH3SH.
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.
