S. Ingemann Jorgensen

Formation and characterization of the sulfur-containing distonic radical anion,E.CH2-S-E-CHCN, in the gas phase

AbstractThe 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-focusing quadrupole hybrid instrument. Deuterium labeling 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-H2+ abstractions to afford isomeric radical anions. High kinetic energy (8 keV) collision-induced charge reversal experiments indicate that the 1,1-H2+.-abstraction leads to a % MathType!MTEF!2!1!+-% feaagaart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaacbaGaa83qai% aa-HeadaWgaaWcbaGaa83maaqabaGccqGHsislcaWFtbGaeyOeI0Ia% b83qayaaraGaeyOeI0Iaa83qaiaa-5eaaaa!3E77!

Experimental determination of the enthalpies of formation of formyl cyanide and thioformyl cyanide in the gas phase.

CH_3 - S - \bar C - CN

Unimolecular and bimolecular chemistry of gas phase ions.

carbene ion, whereas the 1,3-H2+ abstraction yields a novel sulfur-containing distonic radical anion, which is formulated as % MathType!MTEF!2!1!+-% feaagaart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaacbaGaa83qai% aa-HeadaWgaaWcbaGaa8NmaaqabaGccqGHsislcaWFtbGaeyOeI0Ia% b83qayaaraGaa8hsaiabgkHiTiaa-neacaWFobaaaa!3F3F!

Low Pressure Gas-phase Reactions of the Atomic Oxygen Radical Anion with Halomethanes Studied Using Fourier Transform Ion Cyclotron Resonance

CH_2 - S - \bar CH - CN

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

.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-focusing quadrupole hybrid instrument. Deuterium labeling 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 2 (+) abstractions to afford isomeric radical anions. High kinetic energy (8 keV) collision-induced charge reversal experiments indicate that the 1,1-H 2 (+.) -abstraction leads to a [Formula: see text] carbene ion, whereas the 1,3-H 2 (+) abstraction yields a novel sulfur-containing distonic radical anion, which is formulated as [Formula: see text].

Electron transfer as a possible initial step in nucleophilic addition elimination raections between (radical) anions and carbonyl compounds in the gas phase

The loss of ammonia from the metastable molecular ions of cyclic cyano compounds has been examined with the use of deuterium labeling and tandem mass spectrometry. Loss of ammonia is significant for ionized cyanocyclohexane, 1-methyl-, 4-methyl-, 4-cyano-and 4-phenyl-cyanocyclohexanes, 4-cyanopiperidine, cyanocycloheptane and 2-cyanonorbornane. By contrast, loss of ammonia is of minor importance (or absent) for the molecular ions of cyanocyclopentane, 2-methyl-cyanocyclohexane, 1-phenyl-cyanocyclohexane, 1-cyanocyclohexene, 4-cyanotetrahydrothiopyran, 2-cyano-5-norbornene and isocyanocyclohexane. Deuterium labeling of cyanocyclohexane reveals the occurrence of an H-shift from the 4-position to the cyano function, followed by a 1,2-H shift from the 1-position to the C-atom of the newly-formed–CNH group. Subsequently, a series of H-shifts leads to a distonic ion that is formulated as an N-protonated methylamine attached to a cyclohexadienyl radical. Loss of ammonia ensues and leads to ionized toluene as indicated by collision-induced dissociation experiments. For 4-phenyl-cyanocyclohexane, the metastable ions of the cis- and trans-isomers display, essentially, the same unimolecular chemistry. Briefly, the labeling of 4-phenyl-cyanocyclohexane indicates the following: (i) the H atom at the 4-position of the cyclohexane ring is incorporated, to a minor extent, in the ammonia molecule, (ii) loss of NHD2 predominates in the reactions of the molecular ions of 2,2,6,6-d4-4-phenyl-cyanocyclohexane and (iii) the ionized 3,3,5-d3-labeled species expels mainly NH2D. In addition, the metastable molecular ions of the 4-[d5-phenyl]-cyanocyclohexane expel NH3 and NH2D in a ratio of 35:65. A mechanistic scheme is proposed that is consistent with the labeling results for 4-phenyl-cyanocyclohexane as well as the indicated formation of ionized 4-methylbiphenyl as the product ion of ammonia loss.