KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY

ABSTRACT The isomerization reactions of the 4-amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione have been studied theoretically using density functional theory (DFT) along with various exchange-correlation functionals (B3LYP and M06-2x) as well as the benchmark CBS-QB3 quantum chemical approach....

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Autores principales:	Kazeminejad,Zahra, Shiroudi,Abolfazl, Pourshamsian,Khalil, Hatamjafari,Farhad, Oliaey,Ahmad Reza
Lenguaje:	English
Publicado:	Sociedad Chilena de Química 2019
Materias:	Isomerization Rate constant Reaction mechanism Chemical kinetics DFT NBO
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072019000104290
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spelling	oai:scielo:S0717-970720190001042902019-04-11KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORYKazeminejad,ZahraShiroudi,AbolfazlPourshamsian,KhalilHatamjafari,FarhadOliaey,Ahmad Reza Isomerization Rate constant Reaction mechanism Chemical kinetics DFT NBO ABSTRACT The isomerization reactions of the 4-amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione have been studied theoretically using density functional theory (DFT) along with various exchange-correlation functionals (B3LYP and M06-2x) as well as the benchmark CBS-QB3 quantum chemical approach. The calculated energy profile has been supplemented with calculations of kinetic rate constants by means of transition state theory (TST). Based on the optimized isomers geometries using the CBS-QB3 method, a natural bond orbital analysis reveals that the electronic delocalization from non-bonding lone-pair orbitals [LP(e)S7] to the neighboring σN2-C3 antibonding orbital increase from isomer 1 to isomer 2. Also, the LP(e)S7→σN2-C3 delocalizations could fairly explain the increase of occupancies of LP(e) non-bonding orbitals in the ring of isomers 1 and 2 (2 > 1). The electronic delocalization from LP(e)S7 non-bonding to σN2-C3 antibonding orbitals increase the ground state structure stability, Therefore, the increase of LP(e)S7→σN2-C3 delocalizations could fairly explain the kinetics of the isomerization reactions 1 and 2 (k2 > k1). NBO results also suggest that the kinetics of these processes are controlled by LP→σ* resonance energies.info:eu-repo/semantics/openAccessSociedad Chilena de QuímicaJournal of the Chilean Chemical Society v.64 n.1 20192019-03-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072019000104290en10.4067/s0717-97072019000104290
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	Isomerization Rate constant Reaction mechanism Chemical kinetics DFT NBO
spellingShingle	Isomerization Rate constant Reaction mechanism Chemical kinetics DFT NBO Kazeminejad,Zahra Shiroudi,Abolfazl Pourshamsian,Khalil Hatamjafari,Farhad Oliaey,Ahmad Reza KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
description	ABSTRACT The isomerization reactions of the 4-amino-5-methyl-2,4-dihydro-3H-1,2,4-triazole-3-thione have been studied theoretically using density functional theory (DFT) along with various exchange-correlation functionals (B3LYP and M06-2x) as well as the benchmark CBS-QB3 quantum chemical approach. The calculated energy profile has been supplemented with calculations of kinetic rate constants by means of transition state theory (TST). Based on the optimized isomers geometries using the CBS-QB3 method, a natural bond orbital analysis reveals that the electronic delocalization from non-bonding lone-pair orbitals [LP(e)S7] to the neighboring σN2-C3 antibonding orbital increase from isomer 1 to isomer 2. Also, the LP(e)S7→σN2-C3 delocalizations could fairly explain the increase of occupancies of LP(e) non-bonding orbitals in the ring of isomers 1 and 2 (2 > 1). The electronic delocalization from LP(e)S7 non-bonding to σN2-C3 antibonding orbitals increase the ground state structure stability, Therefore, the increase of LP(e)S7→σN2-C3 delocalizations could fairly explain the kinetics of the isomerization reactions 1 and 2 (k2 > k1). NBO results also suggest that the kinetics of these processes are controlled by LP→σ* resonance energies.
author	Kazeminejad,Zahra Shiroudi,Abolfazl Pourshamsian,Khalil Hatamjafari,Farhad Oliaey,Ahmad Reza
author_facet	Kazeminejad,Zahra Shiroudi,Abolfazl Pourshamsian,Khalil Hatamjafari,Farhad Oliaey,Ahmad Reza
author_sort	Kazeminejad,Zahra
title	KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
title_short	KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
title_full	KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
title_fullStr	KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
title_full_unstemmed	KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY
title_sort	kinetics studies on the tautomeric reaction of 4-amino-5-methyl-2,4-dihydro-3h-1,2,4-triazole-3-thione in the gas phase: dft and cbs-qb3 methods using transition state theory
publisher	Sociedad Chilena de Química
publishDate	2019
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072019000104290
work_keys_str_mv	AT kazeminejadzahra kineticsstudiesonthetautomericreactionof4amino5methyl24dihydro3h124triazole3thioneinthegasphasedftandcbsqb3methodsusingtransitionstatetheory AT shiroudiabolfazl kineticsstudiesonthetautomericreactionof4amino5methyl24dihydro3h124triazole3thioneinthegasphasedftandcbsqb3methodsusingtransitionstatetheory AT pourshamsiankhalil kineticsstudiesonthetautomericreactionof4amino5methyl24dihydro3h124triazole3thioneinthegasphasedftandcbsqb3methodsusingtransitionstatetheory AT hatamjafarifarhad kineticsstudiesonthetautomericreactionof4amino5methyl24dihydro3h124triazole3thioneinthegasphasedftandcbsqb3methodsusingtransitionstatetheory AT oliaeyahmadreza kineticsstudiesonthetautomericreactionof4amino5methyl24dihydro3h124triazole3thioneinthegasphasedftandcbsqb3methodsusingtransitionstatetheory
_version_	1714200933935611904

KINETICS STUDIES ON THE TAUTOMERIC REACTION OF 4-AMINO-5-METHYL-2,4-DIHYDRO-3H-1,2,4-TRIAZOLE-3-THIONE IN THE GAS PHASE: DFT AND CBS-QB3 METHODS USING TRANSITION STATE THEORY

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