Protonated hydronium dication, H/sub 4/O/sup 2 +/. Hydrogen-deuterium exchange of D/sub 2/H/sup 17/O/sup +/ in HF:SbF/sub 5/ and DH/sub 2//sup 17/O/sup +/ in DF:SbF/sub 5/ and theoretical calculations

Journal Article · Wed Mar 05 00:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00265a031· OSTI ID:5682442

Olah, G A; Prakash, G K.S.; Barzaghi, M; Lammertsma, K; von R Schleyer, P; Pople, J A

Isotopic hydronium ions D/sub 2/H/sup 17/O/sup +/ and DH/sub 2//sup 17/O/sup +/ in 1:1 (molar) HF:SbF/sub 5//SO/sub 2/ and DF:SbF/sub 2/SO/sub 2/ solutions, respectively, at -15/sup 0/C undergo slow hydrogen-deuterium exchange as monitored by /sup 17/O NMR spectroscopy. The rate of such exchange increases with the increase in the acidity of the fluoroantimonic acid medium (1:2 molar composition). The previously observed lack of exchange of isotopic hydronium ions in the somewhat weaker Magic Acid, FSO/sub 3/H:SbF/sub 5/, medium (H/sub 0/ approx. -21.5) suggests that in the stronger HF:SbF/sub 5/ medium (H/sub 0/ approx. -25 to -28), the exchange occurs through the intermediacy of protonated hydronium dication. Consequently, the structure and stability of protonated hydronium dication has been probed by ab initio theory. The T/sub d/ symmetry structure was found to be the minimum energy structure at the HF/6.31G* level. At the HF/6.31G* level this structure is thermodynamically unstable (dissociation preferred by 59.2 kcal/mol), it seems to have significant kinetic stability (deprotonation barrier 39.4 kcal/mol). 20 references, 1 table.

• Research Organization: Univ. of Southern California, Los Angeles, CA (United States)
• OSTI ID: 5682442
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 108:5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANTIMONY FLUORIDES
ISOTOPIC EXCHANGE
HYDROFLUORIC ACID
OXONIUM IONS
DEUTERIUM COMPOUNDS
EXPERIMENTAL DATA
MATHEMATICAL MODELS
NUCLEAR MAGNETIC RESONANCE
OXYGEN 17
SYMMETRY
THERMODYNAMICS
ANTIMONY COMPOUNDS
CHARGED PARTICLES
DATA
EVEN-ODD NUCLEI
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INFORMATION
INORGANIC ACIDS
IONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MOLECULAR IONS
NUCLEI
NUMERICAL DATA
OXYGEN ISOTOPES
RESONANCE
STABLE ISOTOPES
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation