HOCCO versus OCCO: Comparative spectroscopy of the radical and diradical reactive intermediates

Dixon, Andrew R.; Xue, Ting; Sanov, Andrei

doi:10.1063/1.4953774

Cited by 7 publications

(26 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…17,18 The methylglyoxal solution (40% by weight in water) was first partially dehydrated using 3 Å molecular sieves with a 1:1 volume ratio for at least 24 h, until the solution turned yellowish. Unlike our previous experience with glyoxal, 1,19,20 the methylglyoxal solution did not require any methanol solvent to be extracted from the sieve mixture-it was simply decanted.…”

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Electron affinity and excited states of methylglyoxal

Dauletyarov

Dixon

Wallace

et al. 2017

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Using photoelectron imaging spectroscopy, we characterized the anion of methylglyoxal (XA″ electronic state) and three lowest electronic states of the neutral methylglyoxal molecule: the closed-shell singlet ground state (XA'), the lowest triplet state (aA″), and the open-shell singlet state (AA″). The adiabatic electron affinity (EA) of the ground state, EA(XA') = 0.87(1) eV, spectroscopically determined for the first time, compares to 1.10(2) eV for unsubstituted glyoxal. The EAs (adiabatic attachment energies) of two excited states of methylglyoxal were also determined: EA(aA″) = 3.27(2) eV and EA(AA″) = 3.614(9) eV. The photodetachment of the anion to each of these two states produces the neutral species near the respective structural equilibria; hence, the aA″ ← XA″ and AA″ ← XA″ photodetachment transitions are dominated by intense peaks at their respective origins. The lowest-energy photodetachment transition, on the other hand, involves significant geometry relaxation in the XA' state, which corresponds to a 60° internal rotation of the methyl group, compared to the anion structure. Accordingly, the XA' ← XA″ transition is characterized as a broad, congested band, whose vertical detachment energy, VDE = 1.20(4) eV, significantly exceeds the adiabatic EA. The experimental results are in excellent agreement with the ab initio predictions using several equation-of-motion methodologies, combined with coupled-cluster theory.

show abstract

Section: Experimental and Theoretical Methodsmentioning

confidence: 99%

Electron affinity and excited states of methylglyoxal

Dauletyarov

Dixon

Wallace

et al. 2017

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Sanov and co-workers also reported a comparison of the photoelectron spectra for the m/z = 56 and 57 anions, assigning the latter to ethynediolide (HOCCOˉ). [13] A comparison of the spectra from reference 13 recorded at E hν = 3.49 eV, Figure 3(a), and the spectra in Figure 1 show nearly identical features. The photoelectron spectrum for m/z 56 reported here is consistent with the spectra reported in ref.…”

mentioning

confidence: 76%

“…( 2 A''/A 2 A') [17] Ethynediolide [13] 13, both at E hν = 3.49 eV [13] (adapted from Fig. 1b in ref.…”

Section: Acetone Enolate Radicalmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopy of Ethylenedione and Ethynediolide: A Reinvestigation

et al. 2018

View full text Add to dashboard Cite

In an effort to characterize the electronic states of ethylenedione, OCCO, photoelectronphotofragment coincidence (PPC) spectroscopy was applied to measure anions at m/z 56 and 57 using a pulsed discharge of glyoxal vapor and N 2 O. PPC measurements at a photon energy of 3.20 eV yield photoelectron spectra in coincidence with either neutral photofragments or stable neutral products. The measurements showed that primarily stable neutral products were formed, with photoelectron spectra consistent with the oxyallyl diradical, C 3 H 4 O, and acetone enolate radical, C 3 H 5 O. The spectra were also found to have features nearly identical to those reported for OCCO and HOCCO by Sanov and co-workers. The stability of the neutral products, as well as an examination of spectra reported for the oxyallyl anion and acetone enolate show that the previous assignments of OCCO and HOCCO are in error, and are instead attributed here to the oxyallyl diradical, C 3 H 4 O, and the acetone enolate radical, C 3 H 5 O.

show abstract

“…15,16 The attempt to characterize OCCO from its ion precursors was accomplished very recently at the University of Arizona by Andrei Sanov group. 16,18 The OCCO molecule is created and observed as a short-lived species from its stable radical anion precursor through the photoelectron detachment experiment. The stable radical anion precursor of OCCO in this experiment is produced by the hydrogen abstraction from the glyoxal molecule,…”

mentioning

confidence: 99%

Communication: Low-energy free-electron driven molecular engineering: In situ preparation of intrinsically short-lived carbon-carbon covalent dimer of CO

Davis

Sajeev

2017

The Journal of Chemical Physics

View full text Add to dashboard Cite

Molecular modification induced through the resonant attachment of a low energy electron (LEE) is a novel approach for molecular engineering. In this communication, we explore the possibility to use the LEE as a quantum tool for the in situ preparation of short lived molecules. Using ab initio quantum chemical methods, this possibility is best illustrated for the in situ preparation of the intrinsically short-lived carbon-carbon covalent dimer of CO from a glyoxal molecule. The chemical conversion of glyoxal to the covalent dimer of CO is initiated and driven by the resonant capture of a near 11 eV electron by the glyoxal molecule. The resulting two-particle one-hole (2p-1h) negative ion resonant state (NIRS) of the glyoxal molecule undergoes a barrierless radical dehydrogenation reaction and produces the covalent dimer of CO. The autoionization electron spectra from the 2p-1h NIRS at the dissociation limit of the dehydrogenation reaction provides access to the electronic states of the CO dimer. The overall process is an example of a catalytic electron reaction channel.

show abstract

HOCCO versus OCCO: Comparative spectroscopy of the radical and diradical reactive intermediates

Cited by 7 publications

References 46 publications

Electron affinity and excited states of methylglyoxal

Electron affinity and excited states of methylglyoxal

Spectroscopy of Ethylenedione and Ethynediolide: A Reinvestigation

Communication: Low-energy free-electron driven molecular engineering: In situ preparation of intrinsically short-lived carbon-carbon covalent dimer of CO

Contact Info

Product

Resources

About