Related Experiment Video
Updated: Jun 19, 2026

Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
Published on: October 18, 2018
Photoelectron spectroscopy and thermochemistry of the peroxyformate anion
Stephanie M Villano1, Nicole Eyet, Scott W Wren
1JILA, University of Colorado and the National Institute of Standards and Technology and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, USA.
Abstract:
The 351.1 nm photoelectron spectrum of the peroxyformate anion has been measured. The photoelectron spectrum displays vibronic features in both the 2A'' ground and 2A' first excited states of the corresponding radical. Franck-Condon simulations of the spectrum show that the ion is formed exclusively in the trans-conformation. The electron affinity (EA) of the peroxyformyl radical was determined to be 2.493 +/- 0.006 eV, while the term energy splitting was found to be 0.783-0.020+0.060 eV. Extended progressions in the C-OO (973 +/- 20 cm-1) and O-O (1098 +/- 20 cm-1) stretching modes are observed in the ground state of the radical. The fundamental frequency of the in-plane OCO bend was found to be 574 +/- 35 cm-1. The gas-phase acidity of peroxyformic acid has been determined using an ion-molecule bracketing technique. On the basis of the size of the trans- to cis- isomerization barrier, the measured acidity was assigned to the higher energy trans-conformer of the acid. The gas-phase acidity of the lower energy cis-conformer of peroxyformic acid was found from the measured acidity for the trans-form and a calculated energy correction: DeltaaG298(cis-peroxyformic acid) = 346.8 +/- 3.3 kcal mol-1 and DeltaaH298(cis-peroxyformic acid) = 354.4 +/- 3.3 kcal mol-1. Using a negative ion EA/acidity thermochemical cycle, the O-H bond dissociation energy (D0) values of the trans- and cis-conformers of peroxyformic acid to form the trans-radical were determined to be 94.0 +/- 3.3 and 97.1 +/- 3.3 kcal mol-1, respectively. The heat of formation (DeltafH298) of the trans-peroxyformyl radical was found to be -22.8 +/- 3.5 kcal mol-1.
Related Concept Videos
Hydroboration-Oxidation of Alkenes
Regioselectivity of Electrophilic Additions-Peroxide Effect
Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Autoxidation of Ethers to Peroxides and Hydroperoxides
Radical Formation: Homolysis
Reactivity of Enolate Ions

