Intramolecular hydrogen-bonding effects on OH stretch overtone excitation for fluorinated hydroperoxides

• Novel spectral simulations of OH overtone excitation in fluorinated hydroperoxides.
• Intramolecular H-bonds prevent torsion about the O-O bond and simplify spectra.
• Fluorinated hydroperoxides unlikely for overtone-induced atmospheric chemistry.

Applying computational methods for predicting gas-phase OH stretch overtone spectra to the series of fluorinated hydroperoxides CF3OOH, CHF2OOH, and CH2FOOH reveals how intramolecular hydrogen bonding changes their overtone photochemistry, relative to their un-fluorinated analog CH3OOH. Intramolecular hydrogen bonding between fluorine and the hydroxyl hydrogen atom decreases OH stretch frequencies and raises the barrier for torsion about the OO bond. Whereas OO torsion accompanies OH stretch overtone excitation for CH3OOH, this is not the case for the fluorinated analogs that have intramolecular hydrogen bonding. The comparison highlights the molecular features that contribute to the feasibility of atmospheric overtone-induced OO bond dissociation for CH3OOH, but not for its fluorinated analogs.

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