Theoretical Investigation of Superelectrophilic Fluorooxonium Dications FOH₃²⁺ and F₂OH₂²⁺: Comparison with Parent H₄O²⁺ Dication

Abstract

Structures of the superelectrophilic fluorooxonium dications FOH 3 2+ and F 2OH 2 2+ were calculated at the QCISD(T)/6-311G** level. Proton affinities of their precursor monocationic species were estimated by using G2 theory. For comparison, the parent oxonium dication H 4O 2+ was also calculated at the same level. The O,O- and O,F-diprotonated HFO structures 2c and 2d, respectively, were found to be energy minima. However, the oxonium dication 2c is less stable than the oxonium-fluoronium dication 2d by 14.9 kcal/mol. On the other hand, O,O-diprotonated F 2O 3c was found to be the only minimum for the analogous system. All of these superelectrophilic, dicationic species have substantial kinetic barriers for deprotonations. The possible existence of these dicationic species in either superacidic media or the gas phase is implicated from these studies. The 17O and 19F NMR chemical shifts of the mono- and dictions were also computed by the GIAO-MP2 method.

Department(s)

Chemistry

Sponsor(s)

National Science Foundation (U.S.)
Petroleum Research Fund

Keywords and Phrases

Electronegativity; Oxonium dication; Proton affinity; Superacidic condition; Superelectrophilicity; Chemical bonds; Cyclotron resonance; Fluorine; Fluorine compounds; Nuclear magnetic resonance spectroscopy; Optimization; Polarization; Protons; Reaction kinetics; Positive ions

International Standard Serial Number (ISSN)

1089-5639

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2004 American Chemical Society (ACS), All rights reserved.

Publication Date

01 May 2004

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