On the HNO→HON isomerization mechanism: high level ab initio and density functional theory study

Jalbout, Abraham F.; Darwish, Abdulla M.; Alkahby, Hadi Y.

doi:10.1016/s0166-1280(02)00053-2

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…In the singlet state, the recent ab initio calculations with more than 17,000 data points in the potential energy surface using the sophisticated multi-reference configuration interaction method at the state-averaged complete active space self-consistent field (CASSCF) level [21], show that there are two stable isomers connected via a transition state (TS). This supports previous quantum chemical studies using density functional theory (DFT) methods and ab initio method at the MP2 level [23,24]. Results indicate that the HNO form is the global minimum state in the potential energy surface of the ground state, with the HON isomer of ~40–42 kcal/mol higher in energy, from using various DFT methods, MP2, and other compound methods (G2 and CBS).…”

Section: Structural and Energetic Properties Of Hno Isomerssupporting

confidence: 86%

“…These results suggest that some computed properties of HNO are sensitive to the method of choice [21,24,26–29] and therefore, careful methodological studies need to be performed to find out reasonably good methods for specific property calculations for HNO systems. Our recent methodological investigation of >70 method/basis combinations on the structural and vibrational spectroscopic properties of HNO shows that [29], while the optimized NH and NO bond length errors are within 0.02–0.03 Å, the predicted frequency errors can still be as large as ~170 cm −1 , compared to experimental data [27,30].…”

Section: Structural and Energetic Properties Of Hno Isomersmentioning

confidence: 99%

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Computational investigations of HNO in biology

Zhang

2013

Journal of Inorganic Biochemistry

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HNO (nitroxyl) has been found to have many physiological effects in numerous biological processes. Computational investigations have been employed to help understand the structural properties of HNO complexes and HNO reactivities in some interesting biologically relevant systems. The following computational aspects were reviewed in this work: 1) structural and energetic properties of HNO isomers; 2) interactions between HNO and non-metal molecules; 3) structural and spectroscopic properties of HNO metal complexes; 4) HNO reactions with biologically important non-metal systems; 5) involvement of HNO in reactions of metal complexes and metalloproteins. Results indicate that computational investigations are very helpful to elucidate interesting experimental phenomena and provide new insights into unique structural, spectroscopic, and mechanistic properties of HNO involvement in biology.

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Section: Structural and Energetic Properties Of Hno Isomerssupporting

confidence: 86%

Section: Structural and Energetic Properties Of Hno Isomersmentioning

confidence: 99%

Computational investigations of HNO in biology

Zhang

2013

Journal of Inorganic Biochemistry

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“…Acetaldehyde(CH 3 CHO) is among the most abundant carbonyls in the atmosphere 30. HNO is very important in processes such as pollution formation, energy release in propellants and fuel combustion 31, 32. To the best of our knowledge, no investigations on the interesting red‐shifted and blue‐shifted H‐bonds in the CH 3 CHO…HNO complexes are performed up to now.…”

Section: Introductionmentioning

confidence: 99%

Blue‐shifted and red‐shifted hydrogen bonds: Theoretical study of the CH₃CHO· · ·HNO complexes

Yang

Zhang

Gao

2005

Int J of Quantum Chemistry

106

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The blue‐shifted and red‐shifted H‐bonds have been studied in complexes CH3CHO…HNO. At the MP2/6‐31G(d), MP2/6‐31+G(d,p) MP2/6‐311++G(d,p), B3LYP/6‐31G(d), B3LYP/6‐31+G(d,p) and B3LYP/6‐311++G(d,p) levels, the geometric structures and vibrational frequencies of complexes CH3CHO…HNO are calculated by both standard and CP‐corrected methods, respectively. Complex A exhibits simultaneously red‐shifted CH…O and blue‐shifted NH…O H‐bonds. Complex B possesses simultaneously two blue‐shifted H‐bonds: CH…O and NH…O. From NBO analysis, it becomes evident that the red‐shifted CH…O H‐bond can be explained on the basis of the two opposite effects: hyperconjugation and rehybridization. The blue‐shifted CH…O H‐bond is a result of conjunct CH bond strengthening effects of the hyperconjugation and the rehybridization due to existence of the significant electron density redistribution effect. For the blue‐shifted NH…O H‐bonds, the hyperconjugation is inhibited due to existence of the electron density redistribution effect. The large blue shift of the NH stretching frequency is observed because the rehybridization dominates the hyperconjugation. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006

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“…As far as we know, water is also an abundant species in the organism and the atmosphere. Many previous theoretical studies have concluded that water plays an important catalytic role during the hydrogen migration process of HCN/HNC or HNO/HON 19–24. Thus, it can be predicted that the considerable coupling interaction of either HNS or HSN with water molecules may significantly influence their stability and the isomerization mechanism.…”

Section: Introductionmentioning

confidence: 99%

Different catalysis role of in‐loop and out‐of‐loop waters in assisting HNS/HSN proton transfer isomerizations: Bridging vs. surrounding effect

Yin

Yan

Qin

et al. 2006

Int J of Quantum Chemistry

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ABSTRACT:In this work, a density function theory (DFT) study is presented for the HNS/HSN isomerization assisted by 1-4 water molecules on the singlet state potential energy surface (PES). Two modes are considered to model the catalytic effect of these water molecules: (i) water molecule(s) participate directly in forming a proton transfer loop with HNS/HSN species, and (ii) water molecules are out of loop (referred to as out-of-loop waters) to assist the proton transfer. In the first mode, for the monohydration mechanism, the heat of reaction is 21.55 kcal ⅐ mol Ϫ1 at the B3LYP/6-311ϩϩG** level. The corresponding forward/backward barrier lowerings are obtained as 24.41/24.32 kcal ⅐ mol Ϫ1 compared with the no-water-assisting isomerization barrier T (65.52/43.87 kcal ⅐ mol Ϫ1 ). But when adding one water molecule on the HNS, there is another special proton-transfer isomerization pathway with a transition state 10TЈ in which the water is out of the proton transfer loop. The corresponding forward/backward barriers are 65.89/65.89 kcal ⅐ mol Ϫ1 . Clearly, this process is more difficult to follow than the R-T-P process. For the two-water-assisting mechanism, the heat of reaction is 19.61 kcal ⅐ mol Ϫ1 , compared with T, respectively. But, when four water molecules are involved in the reactant loop, the corresponding energy aspects increase compared with those of the trihydration. The forward/backward barriers are increased by 5.38 and 4.66 kcal ⅐ mol Ϫ1 than the trihydration situation. In the second mode, the outersphere water effect from the other water molecules directly H-bonded to the loop is considered. When one to three water molecules attach to the looped water in one-water in-loop-assisting proton transfer isomerization, their effects on the three energies are small, and the deviations are not more than 3 kcal ⅐ mol Ϫ1 compared with the original monohydration-assisting case. When adding one or two water molecules on the dihydration-assisting mechanism, and increasing one water molecule on the trihydration, the corresponding energies also are not obviously changed. The results indicate that the forward/backward barriers for the three in-loop water-assisting case are the lowest, and the surrounding water molecules (out-of-loop) yield only a small effect.

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On the HNO→HON isomerization mechanism: high level ab initio and density functional theory study

Cited by 8 publications

References 11 publications

Computational investigations of HNO in biology

Computational investigations of HNO in biology

Blue‐shifted and red‐shifted hydrogen bonds: Theoretical study of the CH₃CHO· · ·HNO complexes

Different catalysis role of in‐loop and out‐of‐loop waters in assisting HNS/HSN proton transfer isomerizations: Bridging vs. surrounding effect

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On the HNO→HON isomerization mechanism: high level ab initio and density functional theory study

Cited by 8 publications

References 11 publications

Computational investigations of HNO in biology

Computational investigations of HNO in biology

Blue‐shifted and red‐shifted hydrogen bonds: Theoretical study of the CH3CHO· · ·HNO complexes

Different catalysis role of in‐loop and out‐of‐loop waters in assisting HNS/HSN proton transfer isomerizations: Bridging vs. surrounding effect

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Blue‐shifted and red‐shifted hydrogen bonds: Theoretical study of the CH₃CHO· · ·HNO complexes