Microwave Spectrum Of Triflic Acid Dihydrate And Trihydrate: Evidence For Complete Proton Transfer In A Microsolvated Superacid

Huff, Anna

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https://hdl.handle.net/2142/111607 Copy

Description

Title

Microwave Spectrum Of Triflic Acid Dihydrate And Trihydrate: Evidence For Complete Proton Transfer In A Microsolvated Superacid

Author(s)

Huff, Anna

Contributor(s)

• Leopold, Kenneth R.
• Love, Nathan

Issue Date

2021-06-23

Keyword(s)

Non-covalent interactions

Abstract

Microwave spectra have been observed for the dihydrate and trihydrate of triflic acid (CF$_{3}$SO$_{3}$H-(H$_{2}$O)$_{2}$ and CF$_{3}$SO$_{3}$H-(H$_{2}$O)$_{3}$). For the dihydrate, spectra for CF$_{3}$$^{34}$SO$_{3}$H-(H$_{2}$O)$_{2}$ and CF$_{3}$SO$_{3}$H-(D$_{2}$O)$_{2}$ were also identified. The fitted rotational constants for both the triflic acid dihydrate and trihydrate are in consistently good agreement with those derived from their respective global minimum structures calculated with various DFT methods. The two water molecules in the dihydrate bind to triflic acid in a cyclic arrangement to form an 8-membered ring, resembling an insertion of a second water molecule into the 6-membered ring of the triflic acid monohydrate. For the triflic acid trihydrate, however, rather than form a 10-membered ring via insertion of a third water molecule into the dihydrate geometry, the global minimum structure represents a hydronium triflate ion pair solvated by two water molecules ((CF$_{3}$SO$_{3}$$^{-}$H$_{3}$O$^{+}$)-(H$_{2}$O)$_{2}$). This work represents direct experimental evidence in support of the predicted transition from hydrogen bonding to ion pair formation when triflic acid is solvated with only three water molecules.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Permalink

http://hdl.handle.net/2142/111607

DOI

10.15278/isms.2021.WD01

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