High magnetic field fourier transform ion cyclotron resonance spectroscopy

Allemann, M.; Kellerhals, Hp.; Wanczek, K.P.

doi:10.1016/0020-7381(83)80073-4

Cited by 121 publications

(38 citation statements)

References 5 publications

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“…1) and subsequent exhaustive chlorine using high resolution resonance ejection elimination from the resulting molecular techniques as described elsewhere [8]. ions in the external ion source [ 121 of a Special care was taken to cool the isolated Bruker CMS 47X FT-ICR spectrometer C,+ to ambient temperature by admitting [13] equipped with a 4.7 T superconducting a pressure pulse of argon to the FT-ICR magnet.…”

Section: Methodsmentioning

confidence: 99%

Gas-phase reactions of carbon cluster ions with isomeric chloropropenes

Sun

Grützmacher

Lifshitz

1994

International Journal of Mass Spectrometry and Ion Processes

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Gas-phase ion/molecule reactions of carbon cluster ions (CA', n = 10-20) with allylchloride (AC) and 2-chloropropene (CP) were investigated by Fourier transform ion cyclotron resonance spectrometry (FT-ICR). The carbon cluster ions CA+ were generated by electron impact ionization of perchloroarenes and subsequent elimination of all Cl substituents from the molecular ion giving rise to monocyclic CA'. Clear pseudo-first-order reactions were observed for the carbon cluster ions C;;' thus formed without any sign of isomeric clusters of different reactivity. An exception is Ci:, for which a small amount of unreactive ions was observed. The reactions of Ci' with AC and CP at low operating pressure (1.2 x 1O-8-8.O x IO-'mbar) yield product ions C n+3H: by loss of Cl from an intermediate adduct. Rate constants for the reactions with CP are always distinctly larger than with AC in spite of the smaller dissociation energy of the C-Cl bond in AC. Exceptionally large reaction efficiencies are found for Ci: and Ci:, corroborating the high reactivity of cyclic anti-aromatic CA+ with n = 4r + 1. The nature of the reaction products depends on the number of carbon atoms in CA+. Secondary reactions of primary product ions C n+3H: were observed only for reactions of odd numbered Cit and Ciq. Further, on collision induced dissociation (CID) the product ions from even CA' yield exclusively C3H$, while product ions from odd Cl: generate several fragment ions by loss of H and of Ct2_4jH2. A reaction model explaining these observations is proposed.

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Section: Methodsmentioning

confidence: 99%

Gas-phase reactions of carbon cluster ions with isomeric chloropropenes

Sun

Grützmacher

Lifshitz

1994

International Journal of Mass Spectrometry and Ion Processes

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“…FT-ICR measurements were performed with a Spectrospin CMS 47X FT-ICR spectrometer [8] equipped with a 4.7 T superconducting magnet, a 24 bit/128 k-word ASPECT 3000 computer, a cylindrical cell of 6 cm diameter and 6 cm length, and an external ion source [9]. The radical ions were generated in the external ion source by electron impact (16-20 eV) from the haloanisoles or amines, and were transferred into the ICR cell.…”

Section: Methodsmentioning

confidence: 99%

“…This method allows a correction of erroneous ion abundance measurements as described in detail elsewhere [8]. If more than one product ion is formed in considerable amounts, this method is not very exact, and the determination of the branching ratio in competitive substitutions of two substituents may be less accurate.…”

Section: Methodsmentioning

confidence: 99%

Gas-phase reactions of chloro- and bromoanisoles with methyl- and dimethylamine via radical cations

Thölmann

Hamann

Grützmacher

1994

International Journal of Mass Spectrometry and Ion Processes

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Ionic gas-phase reactions of chloro-and bromoanisoles with CH3NH2 and (CH3)2NH via radical cations were investigated by FT-ICR spectrometry using an external ion source. Protonated N-methylanisidines are formed quantitatively from bromoanisole radical cations with CH3NH2 by ipso substitution of the bromo atom. The analogous reaction of chloroanisole radical cations produce a mixture of protonated and radical cationic N-methylanisidines, the latter ions arising by loss of HCl from the addition complex and corresponding also to ipso substitution products. The branching ratio of product ions and the reaction efficiencies depend on the structure of the haloanisole radical cations, the efficiencies ranging from 1.3% to 24%. The observed dependence of the reactivity on the substitution pattern is in good agreement with earlier results of the reactions of dihalobenzene radical cations with NH3 and shows that all substitution reactions proceed by the same multistep mechanism in which the addition of the amine to the aromatic radical cation in the collision complex is rate determining. The reactions of (CH3)2NH'+ with neutral bromoanisoles in the ICR cell produce protonated N,N-dimethylanisidines besides bromoanisole radical cations by charge exchange. Chloroanisoles produce with (CH3)2NH'+ additionally N,N-dimethylanisidine radical cations by loss of HCl. Deuterium labelling experiments reveal that the H atom eliminated with HCl originates from the amino group. The kinetic behaviour of both substitution processes indicates that branching between loss of Cl and HCl occurs after the rate determining addition step in a chemically activated intermediate. Competition of loss of Cl and by elimination of HCl is observed only for reactions of low reaction efficiencies and is apparently controlled by the excess energy of the excited intermediate adduct.

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“…The experiments were performed on a modified Bruker Spectrospin CMS47X mass spectrometer [36][37][38]. In the new setup in Kiel it is equipped with a 4.7 T unshielded superconducting magnet, an APEX III data station, a Bruker infinity cell, TOPPS ion optics power supply, and an ICC2 Infinity Cell Controller with BCH preamplifier.…”

Section: Methodsmentioning

confidence: 99%

“…After storing the mass selected ion for 10 s at a pressure below 10 -10 mbar as read from the ion gauge, no fragment ions are observed. The peak at m/z = 99.7 is the third harmonics of 6 CoAr + , the peak at m/z = 295 is 36 40 5 Co Ar Ar + , its intensity matching the natural abundance of 36 Ar.…”

Section: Coarmentioning

confidence: 99%

Ion–molecule reactions of CoAr6+ with nitrogen oxides N2O, NO, and NO2: measuring absolute pressure by shock-freezing of the collision complex

Linde

Höckendorf

Balaj

et al. 2010

Low Temperature Physics

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A new method to determine the absolute pressure in an ultra-high vacuum apparatus is tested using ion molecule reactions with 6 CoAr + . In a collision with a neutral reactant, the complex between Co + and the collision partner is stabilized by evaporation of argon atoms. If 6 CoAr + reacts with collision rate, the absolute pressure can be determined by comparing the experimental collision rate with the collision rate calculated from average dipole orientation theory. The experimental results with N 2 O, NO and NO 2 indeed show that the collision complex is frozen out. Comparison of the rates of primary, secondary and tertiary reaction products, however, suggests that not all collisions of 6 CoAr + are reactive. PACS: 82.30.Fi Ion-molecule, ion-ion, and charge-transfer reactions.

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High magnetic field fourier transform ion cyclotron resonance spectroscopy

Cited by 121 publications

References 5 publications

Gas-phase reactions of carbon cluster ions with isomeric chloropropenes

Gas-phase reactions of carbon cluster ions with isomeric chloropropenes

Gas-phase reactions of chloro- and bromoanisoles with methyl- and dimethylamine via radical cations

Ion–molecule reactions of CoAr6+ with nitrogen oxides N2O, NO, and NO2: measuring absolute pressure by shock-freezing of the collision complex

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