Conformational analysis of the tyrosine dipeptide analogue in the gas phase and in aqueous solution by a density functional/continuum solvent model

2002 ◽  
Vol 23 (6) ◽  
pp. 650-661 ◽  
Author(s):  
Emma Langella ◽  
Nadia Rega ◽  
Roberto Improta ◽  
Orlando Crescenzi ◽  
Vincenzo Barone
Keyword(s):  
Aqueous Solution ◽  
Conformational Analysis ◽  
Gas Phase ◽  
Density Functional ◽  
Continuum Solvent Model ◽  
Solvent Model

A Density Functional Study of the Addition of Water to SO3in the Gas Phase and in Aqueous Solution

1998 ◽  
Vol 102 (17) ◽  
pp. 2893-2898 ◽  
Author(s):  
Evert Jan Meijer ◽  
Michiel Sprik
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Density Functional ◽  
Functional Study ◽  
Density Functional Study

scholarly journals Computational Evidence Suggests That 1-chloroethanol May Be an Intermediate in the Thermal Decomposition of 2-chloroethanol into Acetaldehyde and HCl

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar Ventura ◽  
Vincenzo Barone
Keyword(s):  
Aqueous Solution ◽  
Water Molecule ◽  
Gas Phase ◽  
Density Functional ◽  
Water Molecules ◽  
Functional Theory ◽  
Direct Transformation ◽  
The Density Functional Theory ◽  
Successive Step ◽  
The One

<p>The dehalogenation of 2-chloroethanol (2ClEtOH) in gas phase with and without participation of catalytic water molecules has been investigated using methods rooted into the density functional theory. The well-known HCl elimination leading to vinyl alcohol (VA) was compared to the alternative elimination route towards oxirane and shown to be kinetically and thermodynamically more favorable. However, the isomerization of VA to acetaldehyde in the gas phase, in the absence of water, was shown to be kinetically and thermodynamically less favorable than the recombination of VA and HCl to form the isomeric 1-chloroethanol (1ClEtOH) species. This species is more stable than 2ClEtOH by about 6 kcal mol<sup>-1</sup>, and the reaction barrier is 22 kcal mol<sup>-1</sup> vs 55 kcal mol<sup>-1</sup> for the direct transformation of VA to acetaldehyde. In a successive step, 1ClEtOH can decompose directly to acetaldehyde and HCl with a lower barrier (29 kcal mol<sup>-1</sup>) than that of VA to the same products (55 kcal mol<sup>-1</sup>). The calculations were repeated using a single ancillary water molecule (W) in the complexes 2ClEtOH_W and 1ClEtOH_W. The latter adduct is now more stable than 2ClEtOH_W by about 8 kcal mol<sup>-1</sup>, implying that the water molecule increased the already higher stability of 1ClEtOH in the gas phase. However, this catalytic water molecule lowers dramatically the barrier for the interconversion of VA to acetaldehyde (from 55 to 6 kcal mol<sup>-1</sup>). This barrier is now smaller than the one for the conversion to 1ClEtOH (which also decreases, but not so much, from 22 to 12 kcal mol<sup>-1</sup>). Thus, it is concluded that while 1ClEtOH may be a plausible intermediate in the gas phase dehalogenation of 2ClEtOH, it is unlikely that it plays a major role in water complexes (or, by inference, aqueous solution). It is also shown that neither in the gas phase nor in the cluster with one water molecule, the oxirane path is competitive with the VA alcohol path.</p>

Theoretical Conformational Analysis for Neurotransmitters in the Gas Phase and in Aqueous Solution. Serotonin

2005 ◽  
Vol 1 (5) ◽  
pp. 801-816 ◽  
Author(s):  
Giuliano Alagona ◽  
Caterina Ghio ◽  
Peter I. Nagy
Keyword(s):  
Aqueous Solution ◽  
Conformational Analysis ◽  
Gas Phase ◽  
Theoretical Conformational Analysis

scholarly journals Kinetics and thermodynamics of the hydroxylation products in the photodegradation of the herbicide Metolachlor

2020 ◽  
Vol 92 (3) ◽  
pp. 473-484
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Oscar N. Ventura
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Density Functional ◽  
Electronic Structure Calculations ◽  
Kinetic Characteristics ◽  
Kinetics And Thermodynamics ◽  
Composite Methods ◽  
Herbicide Metolachlor ◽  
Kinetics Of ◽  
Structure Calculations

AbstractElectronic structure calculations have been performed to determine the thermochemistry and kinetics of the reaction between OH and the radicals of the S enantiomer of the herbicide Metolachlor, 2-chloro-N-(2-methyl-6-ethylphenyl)-N(2-methoxy-1-methylethyl) acetamide (MC), produced by photoinduced breaking of the C–Cl bond. Both density functional and ab initio composite methods were employed to calculate the structure of reactants, intermediates, transition states and products, in gas phase and in aqueous solution. The expected relative abundance of each product was calculated and compared to the experimentally observed concentrations. It is shown that a combination of thermodynamic and kinetic characteristics interplay to produce the expected theoretical abundances, which turn out to be in agreement with the experimentally observed distribution of products.

Pharmacophore modeling and conformational analysis in the gas phase and in aqueous solution of regioisomeric melatonin analogs. A theoretical and experimental study

2017 ◽  
Vol 1133 ◽  
pp. 534-545 ◽  
Author(s):  
Humberto Mendoza-Figueroa ◽  
Gelacio Martínez-Gudiño ◽  
Jorge E. Villanueva-Luna ◽  
Joel J. Trujillo-Serrato ◽  
Martha S. Morales-Ríos
Keyword(s):  
Aqueous Solution ◽  
Experimental Study ◽  
Conformational Analysis ◽  
Gas Phase ◽  
Pharmacophore Modeling

Density functional study of the Hoffmann elimination of (N-Cl),N-methylethanolamine in gas phase and in aqueous solution

2006 ◽  
Vol 429 (4-6) ◽  
pp. 425-429 ◽  
Author(s):  
D.R. Ramos ◽  
R. Castillo ◽  
M. Canle L. ◽  
M.V. García ◽  
J. Andrés ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Density Functional ◽  
Functional Study ◽  
Density Functional Study
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