Electronic structure of dicarbonyls. Ground state of glyoxal

Dykstra, Clifford E.; Schaefer, Henry F.

doi:10.1021/ja00858a002

Cited by 44 publications

(10 citation statements)

References 5 publications

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“…These results are summarized in the Supporting Information. The computational results find the known stable structures for the cis and trans isomers of the neutral glyoxal, with the trans structure more stable, consistent with previous work [5][6][7][8][9][10][11][12][13][14][15][16]. The energy difference between the two conformers is calculated to be 1625 cm -1 (including only the torsional zero point energy).…”

Section: Resultssupporting

confidence: 87%

“…Bulat et al showed that the greatest contribution to the isomerization barrier in the neutral is such a through-bond interaction [13]. Ionization of glyoxal removes one electron from the HOMO, which corresponds to the non-bonding lone pairs on oxygen, producing a 2 A g ground state, but theory has shown that this orbital is close in energy and mixed in character with the highest π orbital [8]. Ionization here apparently disrupts the π system and destabilizes the cis conformer.…”

Section: Resultsmentioning

confidence: 99%

“…Neutral glyoxal exhibits cis-trans isomerization, and both experimental and theoretical studies have investigated this molecule [5][6][7][8][9][10][11][12][13][14][15][16]. Most of the theoretical work focused on the potential energy surface along the torsional mode.…”

Section: Introductionmentioning

confidence: 99%

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Infrared spectroscopy of the glyoxal radical cation: The charge dependence of internal rotation

Leicht

Cheng

Duncan

2016

Chemical Physics Letters

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Glyoxal radical cations are produced in a pulsed discharge/supersonic molecular beam source. These ions are argon tagged and studied with mass-selected infrared laser photodissociation spectroscopy in the 1500−3500 cm-1 region. Five vibrational resonances are detected, three of which are assigned to two CH stretches and the asymmetric CO stretch fundamentals. Additional bands are assigned to vibrational combinations based on anharmonic frequency calculations. DFT calculations of the internal rotation coordinate, and the comparison of the predicted versus experimental IR spectra, show that the radical cation has only one stable structure, the trans conformer.

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Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

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Infrared spectroscopy of the glyoxal radical cation: The charge dependence of internal rotation

Leicht

Cheng

Duncan

2016

Chemical Physics Letters

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“…Experimental studies of glyoxal [l, 21, biacetyl [3], and various oxalyl halides [4-61 show a clear preference for the trans, planar configuration as the most stable configuration, with glyoxal and oxalyl fluoride possessing a less stable cis configuration, oxalyl chloride a less stable gauche conformation, and biacetyl showing no evidence of any other configuration. Ab initio calculations have also been carried out on glyoxal [7], the oxalyl halides [8], and biacetyl [9]; these are all at least qualitatively supportive of the experimental conclusions. These ab initio based internal rotation potentials have generally been analyzed irr terms of a two-or three-term Fourier expansion.…”

Section: Introductionsupporting

confidence: 53%

Bond–antibond analysis of internal rotation barriers in glyoxal and related molecules: Where INDO fails

Tyrrell

Weinstock

Weinhold

1981

Int J of Quantum Chemistry

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Ab initio and INDO LCBO-MO calculations are carried out on glyoxal, 1,3-butadiene, and acrolein in order to analyze the qualitative failure of INDO-like methods to describe conformation energies in these molecules. Following the method of Brunck and Weinhold for ethanelike systems we identify the principal bond-antibond interactions contributing to the glyoxal barrier, their dependence on dihedral angle and substituent, and their relative magnitudes as calculated by ab initio and INDO SCF-MO theory. We find a gross disparity in the INDO representation of n* interactions which leads to a grossly exaggerated estimate of the stability of gauche conformers in these molecules. These findings appear to have serious implications for the applicability of INDO-like theories to conformational problems in n-bonded molecules, including those of biological interest.

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“…Many theoretical works have also been performed to investigate the electronic spectra of these molecules. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] Ab initio methods such as the symmetry adapted cluster configuration interaction ͑SAC-CI͒, 16 complete active space perturbation theory to second order ͑CASPT2͒, 21,22 multireference Moller-Plesset ͑MRMP͒, 23 and multireference configuration interaction 24,25 ͑MRCI͒ were utilized to calculate the vertical excitation energies of these molecules. In the recent years, the low-lying excited states of trans-1,3-butadiene were intensively examined, in particular, the 2 1 A g and 1 1 B u excited states by MRCI with singles and doubles ͑MR-CISD͒ and multireference averaged quadratic coupled cluster ͑MR-AQCC͒ methods 30 and the 2 1 A g excited state by using a variety of ab initio methods, complete active space selfconsistent field ͑CASSCF͒, CASPT2, multireference singles and doubles configuration interaction ͑MRSDCI͒, and quasidegenerate variational perturbation theory ͑QDVPT͒.…”

Section: Introductionmentioning

confidence: 99%

Singly and doubly excited states of butadiene, acrolein, and glyoxal: Geometries and electronic spectra

Saha

Ehara²,

Nakatsuji³

2006

The Journal of Chemical Physics

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Excited-state geometries and electronic spectra of butadiene, acrolein, and glyoxal have been investigated by the symmetry adapted cluster configuration interaction (SAC-CI) method in their s-trans conformation. Valence and Rydberg states below the ionization threshold have been precisely calculated with sufficiently flexible basis sets. Vertical and adiabatic excitation energies were well reproduced and the detailed assignments were given taking account of the second moments. The deviations of the vertical excitation energies from the experiment were less than 0.3 eV for all cases. The SAC-CI geometry optimization has been applied to some valence and Rydberg excited states of these molecules in the planar structure. The optimized ground- and excited-state geometries agree well with the available experimental values; deviations lie within 0.03 A and 0.7 degrees for the bond lengths and angles, respectively. The force acting on the nuclei caused by the excitations has been discussed in detail by calculating the SAC-CI electron density difference between the ground and excited states; the geometry relaxation was well interpreted with the electrostatic force theory. In Rydberg excitations, geometry changes were also noticed. Doubly excited states (so-called 2 (1)A(g) states) were investigated by the SAC-CI general-R method considering up to quadruple excitations. The characteristic geometrical changes and large energetic relaxations were predicted for these states.

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Electronic structure of dicarbonyls. Ground state of glyoxal

Cited by 44 publications

References 5 publications

Infrared spectroscopy of the glyoxal radical cation: The charge dependence of internal rotation

Infrared spectroscopy of the glyoxal radical cation: The charge dependence of internal rotation

Bond–antibond analysis of internal rotation barriers in glyoxal and related molecules: Where INDO fails

Singly and doubly excited states of butadiene, acrolein, and glyoxal: Geometries and electronic spectra

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