- Application of Thermal Kinetics to Small Carbon Ion Clusters
-
Kinetic energy release distributions (KERDs) were obtained experimentally for unimolecular decomposition of small carbon ion clusters Cn+, n = 10-13 and 18, made by dissociative ionization from perchloro conjugated hydrocarbons.A model-free approach due to Klots, based on the application of thermal kinetics to small systems, allowed the extraction of binding energies for these clusters.The results were found to be in very good agreement with literature values for collisionally activated dissociation (CAD) threshold energies.The ion C11+ demonstrates a particularly high binding energy in agreement with its magic character in Cn+ mass spectra, while C13+ has a relatively low binding energy, reflected in its low abundance in such spectra.
- Lifshitz, Chava,Sandler, Pablo,Gruetzmacher, Hans-Friedrich,Sun, Jing,Weiske, Thomas,Schwarz, Helmut
-
-
Read Online
- Ion/molecule reactions of carbon cluster ions and acrylonitrile
-
Ion/molecule reactions of carbon cluster ions (Cn?+, n = 10-18 and 20) in the gas phase with acrylonitrile (ACN) as the neutral reagent were investigated by Fourier transform ion cyclotron resonance spectrometry (FT-ICR). The carbon cluster ions studied were generated by electron impact ionization of perchlorinated polyaromatic compounds (PPA) and subsequent exhaustive chlorine elimination in the external ion source of the FT-ICR spectrometer. The precursor PPA were prepared by chlorination of the appropriate polyaromatic hydrocarbons using the BMC reagent. The only reaction observed for Cn?+ was the formation of adduct ions stabilized by radiative association (for n = 10-18 and 20) with the exception of C16?+ which stabilized the adduct ion by loss of a neutral C3. The rate constants for the reaction of Cn?+ with ACN vary from kbi = -13 cm3 molecule-1 s-1 (C18?+, C20?+) to kbi = 7.1 × 10-10 cm3 molecule-1 s-1 (C13?+) and are distinctly larger than with HCN and C2H4 studied before. C13?+ and C17?+ exhibit extraordinary reactivity with ACN. For structural information about the product ions Cn+3H3N?+formed from Cn?+ and ACN, collision induced dissociation (CID) spectra were obtained by collision of the accelerated product ions of the ion/molecule reactions with argon gas in the FT-ICR cell for two product ions of sufficient large abundances. In addition, the deprotonation of Cn+3H3N+ (n = 10, 13) product ions by a series of reference bases was studied resulting in a proton affinity of c. 822 and 815 kJ/mol for the conjugate bases C13H2N and C16H2N, respectively.
- Sun, Jing,Grützmacher, Hans-Fr.,Lifshitz, Chava
-
p. 8382 - 8388
(2007/10/02)
-
- Extensive Chlorination of Methylnaphthalenes, Friedel-Crafts Alkylation of Pentachlorobenzene by Heptachloro(chloromethyl)naphthalenes, and Related Results
-
The chlorination of 2-methylnaphthalene (1) and 1-methylnaphthalene (12) by means of Silberrad's reagent (initial components: SO2Cl2, S2Cl2, and AlCl3) has been performed.From 1 or 12, the following compounds have been synthesized for first time: nonachlo
- Garcia, R.,Riera, J.,Carilla, J.,Julia, L.,Molins, E.,Miravitlles, C.
-
p. 5712 - 5719
(2007/10/02)
-
- Synthesis and Crystallography of 1,2,3,4,6,7-Hexachloronaphthalene and 1,2,3,5,6,7-Hexachloronaphthalene
-
1,2,3,4,6,7-Hexachloronaphthalene (5) and 1,2,3,5,6,7-hexachloronaphthalene (6) have been synthesized via reductive dehalogenation of octachloronaphthalene by lithium aluminium hydride.The reduction proceeds via the substitution of one of the chlorine atoms in an α-position and the formation of 1,2,3,4,5,6,7-heptachloronaphthalene (4).The two sterically more crowded α-positions (positions four and five) in the heptachloronaphthalene were found to be preferentially reduced as the reduction proceeds.Only trace amounts of other isomers were formed.Crystal and molecular structure of the two title isomers were determined by single crystal X-ray diffraction methods.The compounds crystallize in the space group P21/c with the following cell dimensions: 5, a = 14.71(2) Angstroem, b = 3.828(4) Angstroem, c = 20.45(3) Angstroem, and β = 87.8(1) deg; 6, a = 9.381(4) Angstroem, b = 3.807(2) Angstroem, c = 16.168(8) Angstroem and β = 102.40(4) deg.The structures were determined by direct methods and the obtained models containing total of 95 parameters for 5 and 48 parameters for 6 were refined by full-matrix least-squares calculations that gave a final R value of: 5, 0.0619 for 486 unique reflections with I/?(I) 3 and 6, 0.0592 for 382 unique reflections with I/?(I) 3.
- Jakobsson, Eva,Eriksson, Lars,Bergman, Ake
-
p. 527 - 532
(2007/10/02)
-