Gas-Phase Reactions of Nitronium Ions with Acetylene and Ethylene: An Experimental and Theoretical Study

Abstract

A comparative study of the gas-phase reactions of NO 2 with acetylene and ethylene was performed by using FT-ICR, MIKE, CAD, and N f R/ CA mass spectrometric techniques, in conjunction with ab initio calculations at the MP2/6 ± 31 G* level of theory. Both reactions proceed according to the same mechanism, that is, 1,3-dipolar cycloaddition, but yield products of different stability. The C 2 H 2 NO 2 adduct from acetylene has an aromatic character and hence is highly stabilized with respect to the C 2 H 4 NO 2 adduct from ethylene. Both cycloadducts tend to isomerize into O-nitroso derivatives, that is, nitrosated ketene and nitrosated acetaldehyde, which represent the thermodynamically most stable products from the addition of NO 2 to acetylene and ethylene, respectively. As prototypal examples of the reactivity of free nitronium ions with most simple p systems, the reactions investigated are useful starting points to model the mechanism of aromatic nitration.

Isotope exchange in disulfur monoxide-water charged complexes: A mass spectrometric and computational study

“…The experiments were performed using a modified ZABSpec oa-TOF instrument (Waters/VG Micromass, Hertfordshire, UK) of EBE-TOF configuration, where E and B stand for electric and magnetic sectors, respectively, and TOF stands for orthogonal time-of-flight mass spectrometer [16]. The instrument was fitted with an EI/CI (electron ionization/chemical ionization) source, a gas cell located in the first field-free region, and two pairs of cells located after the magnet in the second field-free region and in the TOF sector, respectively.…”

Study of gas‐phase reactions of NO2+ with aromatic compounds using proton transfer reaction time‐of‐flight mass spectrometry

“…The reaction mechanism for NO 2 + reacting with benzene is shown in Figure . NO 2 + in its ground state is linear, with 2 orthogonal π systems . The NO 2 + electrophilic attack of ArXs will form a π‐complex, and the bond angle of ONO will change due to spin coupling .…”

“…It may play some roles in the heterogeneous chemistry of polar stratospheric clouds . While the study of ion chemistry involving the NO 2 + is currently the focus of considerable fundamental interest and is relevant in diverse fields ranging from mechanistic organic chemistry to atmospheric chemistry, clustering, and nucleation phenomena . Aromatic compounds (ArXs) comprise 20% to 50% of the nonmethane hydrocarbon mass in urban air and are regarded as some of the main precursors to secondary organic aerosols (SOA), which constitute up to 80% of the total organic aerosol in the atmosphere .…”

“…In the 1970s, gas‐phase reactions of NO 2 + with ArX were studied by ion cyclotron resonance mass spectrometry at a pressure of 10 −5 Torr, and the competing reaction mechanisms were found to be electron transfer to form ArX + and substitution to form ArXO + . Later, a few gas‐phase reactions between NO 2 + and organic compounds have been studied by ion cyclotron resonance mass spectrometry or triple quadrupole mass spectrometry and theoretical calculations with ab initio methods . However, these techniques are not sufficient for investigations of the gas‐phase ion chemistry for NO 2 + , especially gas‐phase reactions between NO 2 + and ArXs.…”

Linking Ion and Neutral Chemistry in CH Bond Electrophilic Activation: Generation and Detection of HO2. Reactive Radicals in the Gas Phase

“…[19] High-resolution CI spectra were recorded at 25 000 full width at half maximum (fwhm) at the first detector, to rule out isobaric contaminations and assign the elemental composition [C, H 2 , F 2 , 18 O 2 ]C + . [19] High-resolution CI spectra were recorded at 25 000 full width at half maximum (fwhm) at the first detector, to rule out isobaric contaminations and assign the elemental composition [C, H 2 , F 2 , 18 O 2 ]C + .…”