Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase

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Title:Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase
Creators:
Mazurek, Ulf
Schröder, Detlef
Schwarz, Helmut
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 63, 9, pp. 1498-1512
Uncontrolled Keywords:C-H bond activation, Gas-phase ion chemistry, Oxidation state, Electron transfer, Chromium fluorides

Abstract

Gaseous chromium fluoride monocations CrF<sub><i>n</i></sub><sup>+</sup> (<i>n</i> = 1-4) can be prepared by sequential fluorine-atom transfer from nitrogen trifluoride, NF<sub>3</sub>, to chromium cation. In addition, formal F<sup>-</sup> anion transfer to CrF<sub><i>n</i></sub><sup>+</sup> (<i>n</i> = 2-4) to yield the corresponding neutral chromium fluorides CrF<sub><i>n</i>+1</sub> is observed. In conjunction with a re-evaluation of previous data, the present results provide a consistent picture of the thermochemistry of neutral and cationic chromium fluorides. The reactivity of the CrF<sub><i>n</i></sub><sup>+</sup> ions towards alkanes is investigated in a Fourier-transform ion cyclotron resonance mass spectrometer. While "bare" Cr<sup>+</sup> does not react with alkanes, the chromium fluoride cations CrF<sub><i>n</i></sub><sup>+</sup> do; CrF<sub>3</sub><sup>+</sup> and CrF<sub>4</sub><sup>+</sup> are even capable of activating methane. With both increasing oxidation state of chromium and increasing chain lengths of the alkane, the branching ratio of the possible reaction pathways shifts from homolytic C-H and C-C bond activation to hydride- and methanide-ion transfer to yield carbocations, and finally electron transfer generating hydrocarbon radical cations.

Title:Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase
Creators:
Mazurek, Ulf
Schröder, Detlef
Schwarz, Helmut
Uncontrolled Keywords:C-H bond activation, Gas-phase ion chemistry, Oxidation state, Electron transfer, Chromium fluorides
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:63
Number:9
Page Range:pp. 1498-1512
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19981498UNSPECIFIED
ID Code:1396
Item Type:Article
Deposited On:06 Feb 2009 17:09
Last Modified:06 Feb 2009 16:09

Citation

Mazurek, Ulf; Schröder, Detlef; Schwarz, Helmut (1998) Generation and Reactivity of Chromium Fluoride Cations (CrF+n, n = 0-4) in the Gas Phase. Collection of Czechoslovak Chemical Communications, 63 (9). pp. 1498-1512. ISSN 0010-0765

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