A quantum-chemical study of the thermodynamic properties of the CNOH3 isomers

Туровцев, В. В.; Stepnikov, I. V.; Kizin, A. N.; Orlov, Yu. D.

doi:10.1134/s0036024407020318

Cited by 3 publications

(2 citation statements)

References 23 publications

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“…report

and

, both in units of J K −1 mol −1 , for HC(O)NH 2 at 298.15 K, compared to our values of

and

. Unusually they also report

and

J K −1 mol −1 for ( E,Z )‐methanimidic acid 74 …”

Section: Computational Resultssupporting

confidence: 67%

“…In a quantum-chemical study of the thermodynamic properties of the CNOH for (E,Z)-methanimidic acid. 74 At 300 and 1000 K Bauder and Günthard 75 report an enthalphy function (𝐻 − • 𝑇 − 𝐻 − • 0 ) of 10.84 and 63.85 kJ mol −1 , respectively, for HC(O)NH 2 which compare reasonably with our 12.53 and 68.67 kJ mol −1 which were computed via anharmonic vibrational modes including 1D-hindered rotors via Thermo. Their entropy values at 300 and 1000 K are 248.7 and 333.5 J K −1 mol −1 , compared to our 258.7 and 349.76 J K −1 mol −1 .…”

Section: Thermochemistrysupporting

confidence: 79%

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Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

Würmel

Simmie

2023

Int J of Chemical Kinetics

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A number of amides, RC(O)NH 2 , have been detected spectroscopically in the space between the stars. Naturally the study of how these are formed is an important question on the path of chemical evolution from the elements C, H, N, O, P, . . . to life because the so-called peptide-bond −C(O)−NH− is a key linkage in poly-amino acids or proteins. Both cyanides and water are abundant in the interstellar medium (ISM) and it has been suggested [J Phys Chem A. 2021;126:924-939] that these react on water-ice grains, catalyzed by acid H 3 O + , to form firstly imidic acids R−C≡N + H 2 O → RC(OH)NH and subsequently to amides. Here we explore the kinetics in the gas-phase of the intramolecular tautomerization reaction of the imidic acids for R = H, HO, NC, H 2 N, HC(O), H 3 C, HOCH 2 , H 2 CCH,H 3 C(O), H 2 NCH 2 , C 2 H 5 , and CN, particularly at low temperatures where quantum mechanical small curvature and quantized reactant states tunneling are dominant. The most reactive imidic acid is H 2 NC(OH)NH which goes on to form urea, one of three known amides in the interstellar medium (ISM), which can self-react to form cytosine and uracil two canonical nucleobases in RNA. The thermochemistry (Δ 𝑓 𝐻 − • , 𝑆 − • , 𝐶 − • 𝑝 , {𝐻 𝑇 − 𝐻 0 }) of the imidic acids and amides is also reported as well as the tautomerization of sulfur and phosphorus analogs HC(SH)NH and HC(OH)PH.

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“…report

and

, both in units of J K −1 mol −1 , for HC(O)NH 2 at 298.15 K, compared to our values of

and

. Unusually they also report

and

J K −1 mol −1 for ( E,Z )‐methanimidic acid 74 …”

Section: Computational Resultssupporting

confidence: 67%

Section: Thermochemistrysupporting

confidence: 79%

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

Würmel

Simmie

2023

Int J of Chemical Kinetics

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A Database of Formation Enthalpies of Nitrogen Species by Compound Methods (CBS-QB3, CBS-APNO, G3, G4)

Simmie

2015

J. Phys. Chem. A

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Accurate thermochemical data for compounds containing C/H/N/O are required to underpin kinetics simulation and modeling of the reactions of these species in different environments. There is a dearth of experimental data so computational quantum chemistry has stepped in to fill this breach and to verify whether particular experiments are in need of revision. A number of composite model chemistries (CBS-QB3, CBS-APNO, G3, and G4) are used to compute theoretical atomization energies and hence enthalpies of formation at 0 and 298.15 K, and these are benchmarked against the best available compendium of values, the Active Thermochemical Tables or ATcT. In general the agreement is very good for some 28 species with the only discrepancy being for hydrazine. It is shown that, although individually the methods do not perform that well, collectively the mean unsigned error is <1.7 kJ mol(-1); hence, this approach provides a useful tool to screen published values and validate new experimental results. Using multiple model chemistries does have some drawbacks but can produce good results even for challenging molecules like HOON and CN2O2. The results for these smaller validated molecules are then used as anchors for determining the formation enthalpies of larger species such as methylated hydrazines and diazenes, five- and six-membered heterocyclics via carefully chosen isodesmic working reactions with the aim of resolving some discrepancies in the literature and establishing a properly validated database. This expanded database could be useful in testing the performance of computationally less-demanding density function methods with newer functionals that have the capacity to treat much larger systems than those tested here.

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Gas phase identification of the elusive oxaziridine (cyclo-H₂CONH) – an optically active molecule

et al. 2020

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A quantum-chemical study of the thermodynamic properties of the CNOH3 isomers

Cited by 3 publications

References 23 publications

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

A Database of Formation Enthalpies of Nitrogen Species by Compound Methods (CBS-QB3, CBS-APNO, G3, G4)

Gas phase identification of the elusive oxaziridine (cyclo-H₂CONH) – an optically active molecule

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A quantum-chemical study of the thermodynamic properties of the CNOH3 isomers

Cited by 3 publications

References 23 publications

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH2: Kinetic implications for the formation of peptide bonds in the interstellar medium

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH2: Kinetic implications for the formation of peptide bonds in the interstellar medium

A Database of Formation Enthalpies of Nitrogen Species by Compound Methods (CBS-QB3, CBS-APNO, G3, G4)

Gas phase identification of the elusive oxaziridine (cyclo-H2CONH) – an optically active molecule

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Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

Substituent effects in the tautomerization of imidic acids R−C(OH)=NH → R−C(O)NH₂: Kinetic implications for the formation of peptide bonds in the interstellar medium

Gas phase identification of the elusive oxaziridine (cyclo-H₂CONH) – an optically active molecule