Formation and characterization of the sulfur-containing distonic radical anion, , in the gas phase, in the gas phase

Abstract

Formation and characterization of the sulfur-containing distonic radical anion,E.CH2-S-E-CHCN, in the gas phase Born, M.; Ingemann Jorgensen, S.; Nibbering, N.M.M. Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. The reactions of the atomic oxygen radical anion O-with CH3--S--CH2--CN m the gas phase have been examined with Fourier transform ion cyclotron resonance in combination with tandem mass spectrometric experiments performed with a double-focusmg quadrupole hybrid mstrument. Deuterium labelmg has revealed that the O-ion reacts with CH3--S--CH2--CN by proton abstraction from the methylene group as well as by competing 1,1-and 1,3-H~ abstractions to afford isomeric radical anions. High kinetic energy (8 keV) collision-induced charge reversal experiments mdicate that the 1,1-H~-'-abstraction leads to a CHB--S--C'--CN carbene ion, whereas the 1,3-H~ abstraction yields a novel sulfur-containing distomc radical anion, wt'uch is formulated as "CH2--S--CH--CN. (J Am Soc Mass Spectrom 1995, 6, 71-75)

Experimental Determination of the Enthalpies of Formation of Formyl Cyanide and Thioformyl Cyanide in the Gas Phase

“…A series of high kinetic energy (8 keV) collision-induced dissociation (CID) experiments were performed (see the Experimental Section) in order to determine the structure of the various ions. The ions formed by proton abstraction from methoxyacetonitrile eliminate only a methyl radical upon 8 keV collision-induced dissociation, as observed earlier in drift-cell ICR studies, , and a similar observation is reported for the related ions generated from thiomethoxyacetonitrile, as described in a previous report . The collision-induced charge-reversal (CR) spectrum of the carbanion of the methoxyacetonitrile is shown in Figure .…”

“…The generation of the ions given in eqs 4−7 upon charge reversal and also the other ionic species formed (see Figure ) are in line with the carbanion structure shown in eq 1. For the related ion from thiomethoxyacetonitrile, a similar conclusion has been reached previously also on the basis of CR experiments . The charge-reversal spectrum of the ions formed by methyl radical loss from the carbanion of methoxyacetonitrile is shown in Figure , while the spectrum for the related sulfur-containing species is shown in Figure .…”

“…In an earlier study from our group, it was observed that the carbanion, CH 3 OC hHCN, derived from methoxy acetonitrile expels readily upon excitation a methyl radical in the gas phase with the formation of the molecular radical anion of formyl cyanide, HC(O)CN •-. 16 A similar process is observed for the CH 3 SC h HCN carbanion generated from thiomethoxyacetonitrile, 17 thus providing an experimental entry to the formation of the radical anion of thioformyl cyanide, HC(S)CN •-. The relatively facile formation of the molecular radical anions of the formyl and thioformyl cyanides in the gas phase allows for experimental insight into the thermodynamic properties of these species to be gained.…”

Generation and Chemistry of Fluorinated Acetoxyl and Oxyallyl Biradical Anions (Distonic Radical Anions) in the Gas Phase

“…Biradical ions (distonic radical ions) are of great interest because they are key intermediates in some reactions, − they are biologically important, they can be used to study the reactivities of radicals in the gas phase using the charge as a detection tool in mass spectroscopy, , they have unique chemical properties ,− which are not seen in conventional radical ions, and they can be used to study the singlet−triplet energy gaps in the corresponding neutral biradicals. − Although numerous distonic radical anions have been generated using various methods, ,− there are relatively few published studies of their chemical reactivity in the gas phase. − , Most of the previously studied distonic radical anions were formed via oxygen radical anion (O •- ) abstraction of H 2 •+ from a neutral precursor. ,, The products from these reactions are often a mixture of isomersdistonic radical anions and conventional radical anionswith the same m/z that are not easily distinguishable by mass spectroscopy . Since the presence of isomeric ions makes chemical studies of distonic radical anions difficult, only a few have been studied successfully using this method (most notably, the distonic 1,4-radical anion of tetramethyleneethane 8 ).…”

New Approach to Carbene Chemistry via Distonic Carbene Ions. A Case of Spin-Forbidden Proton Transfer and Carbene−Biradical Tautomerism

“…In these species, the charged and radical or biradical moieties are formally separate, and when the charged site is chemically inert, reactions of the radical or biradical portion of the molecule can be observed. Free radical reactions of distonic radical cations − and anions − have been investigated by several groups. We reported the generation of distonic biradical anions in the gas phase and a characterization of their spin-state-dependent reactivity …”