Conformational stability, structural parameters and vibrational assignment from variable temperature infrared spectra of xenon and krypton solutions and ab initio calculations of ethylisocyanate

Durig, J. R.; Zhou, Sarah Xiaohua; Zheng, Chao; Durig, D. T.

doi:10.1016/j.molstruc.2010.02.066

Cited by 6 publications

(7 citation statements)

References 24 publications

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“…Apart from the ground vibrational state, three vibrational satellites could be observed in the spectrum. These satellites were assigned to three successive excitations ( υ t = 1, 2, 3) of C—N torsional mode ν t , which is expected to be the lowest frequency mode (Durig et al 2010; Sullivan et al 1987; Sakaizumi et al 1976). A torsional frequency of about 40 cm −1 can be roughly estimated from the relative intensity measurements.…”

Section: Rotational Spectra and Analysismentioning

confidence: 99%

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Kolesníková

Alonso

Tercero

et al. 2018

A&A

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Context. Relatively high abundances of methyl isocyanate (CH 3 NCO), a methyl derivative of isocyanic acid (HNCO), found in the Orion KL and Sgr B2 molecular clouds suggest that its ethyl derivative, ethyl isocyanate (CH 3 CH 2 NCO), may also be present. Aims. The aim of this work is to provide accurate experimental frequencies of ethyl isocyanate in its ground and excited vibrational states in the millimeter wave region to support searches for it in the interstellar medium. Methods. The rotational spectrum of ethyl isocyanate was recorded at room temperature from 80 to 340 GHz using the millimeter wave spectrometer in Valladolid. Assigned rotational transitions were analyzed using the S -reduced semirigid-rotor Hamiltonian. Results. More than 1100 distinct frequency lines were analyzed for the ground vibrational state of the cis conformer as well as for three vibrational satellites corresponding to successive excitation of the lowest-frequency C-N torsional mode. Newly determined rotational and centrifugal distortion constants were used for searches of spectral features of ethyl isocyanate in Orion KL and Sgr B2 clouds. Upper limits to CH 3 CH 2 NCO in these high-mass star-forming regions were obtained.

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Section: Rotational Spectra and Analysismentioning

confidence: 99%

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Kolesníková

Alonso

Tercero

et al. 2018

A&A

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“…An overview of the existing literature indicates a severe lack of chemical diversity in systems studied so far (Figure ). Most research thus far has been limited to first and second row elements in the periodic table ,,,− …”

Section: Introductionmentioning

confidence: 99%

Torsional Potentials of Glyoxal, Oxalyl Halides, and Their Thiocarbonyl Derivatives: Challenges for Popular Density Functional Approximations

Tahchieva

Bakowies

Ramakrishnan

et al. 2018

J. Chem. Theory Comput.

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The reliability of popular density functionals was studied for the description of torsional profiles of 36 molecules: glyoxal, oxalyl halides, and their thiocarbonyl derivatives. HF and 18 functionals of varying complexity, from local density to range-separated hybrid approximations and double-hybrid, have been considered and benchmarked against CCSD(T)-level rotational profiles. For molecules containing heavy halogens, most functionals fail to reproduce barrier heights accurately and a number of functionals introduce spurious minima. Dispersion corrections show no improvement. Calibrated torsion-corrected atom-centered potentials rectify the shortcomings of PBE and also improve on σ-hole based intermolecular binding in dimers and crystals.

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“…These studies have been followed with spectroscopic and theoretical studies of ethylisothiocyanate (CH 3 CH 2 NCS) 3 and ethylisocyanate (CH 3 CH 2 NCO). 4 For the thio-compound, it was concluded from the microwave spectra 5 that the most stable conformer was the trans form, whereas from ab initio calculations 6 at the MP2 level with various basis sets up to TZVP, it was concluded that the gauche form was the most stable form. However, from a more recent spectroscopic and theoretical study 7 using larger basis sets it was conclusively shown that the most stable form was the cis conformer.…”

Section: ' Introductionmentioning

confidence: 99%

“…We initiated these recent studies by investigations of methylisothiocyanate (CH 3 NCS) and methylisocyanate (CH 3 NCO), where free internal rotation was observed for the methyl rotors for both molecules and the r 0 structural parameters were determined. These studies have been followed with spectroscopic and theoretical studies of ethylisothiocyanate (CH 3 CH 2 NCS) and ethylisocyanate (CH 3 CH 2 NCO) . For the thio- compound, it was concluded from the microwave spectra that the most stable conformer was the trans form, whereas from ab initio calculations at the MP2 level with various basis sets up to TZVP, it was concluded that the gauche form was the most stable form.…”

Section: Introductionmentioning

confidence: 99%

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Conformational Stability from Variable Temperature Infrared Spectra of Xenon Solutions, r₀ Structural Parameters, and Ab Initio Calculations of Cyclopropylisocyanate

et al. 2011

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Infrared spectra (4000 to 400 cm(-1)) of the gas and variable temperature xenon solutions, and the Raman spectrum of the liquid have been recorded for cyclopropylisocyanate. The enthalpy difference has been determined to be 77 ± 8 cm(-1) (0.92 ± 0.10 kJ/mol) with the trans form more stable than the cis conformer with 59 ± 2% present at ambient temperature. By utilizing three rotational constants for each conformer, combined with structural parameters predicted from MP2(full)/6-311+G(d,p) calculations, the adjusted r(0) parameters have been obtained. Heavy atom structural parameters for the trans [cis] conformers are the following: distances (Å) (C-C(2,3)) = 1.509(3) [1.509(3)], (C(2)-C(3)) = 1.523(3) [1.521(3)], (C-N) = 1.412(3) [1.411(3)], (N═C) =1.214(3) [1.212(3)], (C═O) = 1.163(3) [1.164(3)]; angles (°) ∠CCN = 116.7(5) [120.1(5)], ∠CNC = 136.3(5) [137.6(5)]. The centrifugal distortion constants have been predicted from ab initio and DFT calculations and are compared to the experimentally determined values.

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Conformational stability, structural parameters and vibrational assignment from variable temperature infrared spectra of xenon and krypton solutions and ab initio calculations of ethylisocyanate

Cited by 6 publications

References 24 publications

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Torsional Potentials of Glyoxal, Oxalyl Halides, and Their Thiocarbonyl Derivatives: Challenges for Popular Density Functional Approximations

Conformational Stability from Variable Temperature Infrared Spectra of Xenon Solutions, r₀ Structural Parameters, and Ab Initio Calculations of Cyclopropylisocyanate

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Conformational stability, structural parameters and vibrational assignment from variable temperature infrared spectra of xenon and krypton solutions and ab initio calculations of ethylisocyanate

Cited by 6 publications

References 24 publications

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Millimeter wave spectra of ethyl isocyanate and searches for it in Orion KL and Sagittarius B2

Torsional Potentials of Glyoxal, Oxalyl Halides, and Their Thiocarbonyl Derivatives: Challenges for Popular Density Functional Approximations

Conformational Stability from Variable Temperature Infrared Spectra of Xenon Solutions, r0 Structural Parameters, and Ab Initio Calculations of Cyclopropylisocyanate

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Conformational Stability from Variable Temperature Infrared Spectra of Xenon Solutions, r₀ Structural Parameters, and Ab Initio Calculations of Cyclopropylisocyanate