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Your search keyword '"de la Moya Cerero, Santiago"' showing total 92 results
Start Over Author "de la Moya Cerero, Santiago" Publication Type Academic Journals
92 results on '"de la Moya Cerero, Santiago"'

4. Evidence for different types of water participation in the solvolysis of 1-aamantyl, tert-butyl, and methyl chlorides from density functional theory computations

Author

Garcia Martinez, Antonio, Teso Vilar, Enrique, Osio Barcina, Jose, and de la Moya Cerero, Santiago

Subjects
Density functionals -- Usage, Hydrolysis -- Research, Chlorobutane -- Atomic properties, Chlorobutane -- Chemical properties, Chloromethane -- Atomic properties, Chloromethane -- Chemical properties, Biological sciences, Chemistry
Abstract

The activation energy in the gas phase and the free energy of activation in water solution for the hydrolysis of the monohydrates of methyl chloride (MeCl), tert-butyl chloride (t-BuCl), and 1-adamantyl chloride (AdCl) is computed with the B3LYP/631-G(d) method and the polarizable continuum (PCM) solvation model. There is a fair agreement between the free of activation values computed and the experimental data.

Published
2005

9. Solvent and stereoelectronic effects on the solvolysis rates of oxaspirocyclopropanated 1-norbornyl triflates and related bridgehead derivatives

Author

Martinez, Antonio Garcia, de la Moya Cerero, Santiago, Vilar, Enrique Teso, Fraile, Amelia Garcia, Maroto, Beatriz Lora, and Morillo, Cristina Diaz

Subjects
Stereochemistry -- Research, Carbon compounds -- Chemical properties, Biological sciences, Chemistry
Abstract

Experimental and computational studies were conducted to examine the stereochemical solvolytic behavior of oxaspirocyclopropanated 1-norbornyl triflates. The results provide insight into the linear correlation in the gas-phase calculations for rearrangement of the intermediate carbocations due to unspecific solvent effects on the solvolysis rates.

Published
2008

11. About the Existence of Organic Oxonium Ions as Mechanistic Intermediates in Water Solution.

Author

de la Moya Cerero, Santiago, Siehl, Hans-Ullrich, and Martínez, Antonio García

Subjects
*OXONIUM ions, *INTERMEDIATES (Chemistry), *WATER chemistry, *SOLUTION (Chemistry), *HYDRATION, *CARBOCATIONS
Abstract

This paper is aimed to show overwhelming experimental and theoretical evidence supporting the existence of organic oxonium ions (ROH2+) as mechanistic intermediates in water solution, which should be taken into account when describing important reactions, like hydrations of carbocations or C-O cleavages under acidic conditions. For the hydration reaction of tert-butyl (t-Bu+) cation, we have calculated the reaction rate between the intermediate hydrated cation t-BuOH2+ and water, showing that the concerted proton/electron transfer reaction (CPET) is very slow in comparison with experimental data. Much better accordance is achieved by assuming a sequential electron transfer/proton transfer reaction (ETPT). Thus, there is an excellent accordance between the calculated relaxation time (τ = 2.14 ps) for the ETPT process in water and experimentally determined τ values (1.0-1.5 ps) for related reactions. Moreover, there is also an excellent agreement between the potential energy of activation (ΔVTS≠ = 3.17 kcal/mol) for the proton transfer in gas-phase, computed with the B3LYP/6-31G(d) method following the variational transition state theory (VTST), with the analogous ΔV(QEQ)≠ value (3.09 kcal/mol), calculated using methods based on single electron transfer (SET) reactions. [ABSTRACT FROM AUTHOR]

Published
2016
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20. The Mechanism of Hydrolysis of Aryldiazonium Ions Revisited: Marcus Theory vs. Canonical Variational Transition State Theory.

Author

García Martínez, Antonio, de la Moya Cerero, Santiago, Osío Barcina, José, Moreno Jiménez, Florencio, and Lora Maroto, Beatriz

Subjects
*HYDROLYSIS, *PROPERTIES of matter, *SOLUTION (Chemistry), *ELECTROLYSIS, *ANALYTICAL chemistry
Abstract

Several models, theoretical levels and computational methods, all based on the canonical variational transition state approximation, have been used to predict both the experimental activation energies (Δ Eexp≠) and the experimental activation free energies (Δ Gexp≠) for the hydrolysis of aryldiazonium ions. It is demonstrated that the computation of activation energies (Δ E≠), instead of activation free energies (Δ G≠), agrees better with the corresponding experimental data, showing that the employed computational methods do not afford reliable entropic contributions to the free energy barriers in the case of the studied reaction. However, the most fitted computations of Δ E≠ were not able to clearly differentiate between the mechanisms proposed for this interesting reaction (SN1, SN2 and water cluster). In contrast, the use of the Marcus theory (hyperbolic-cosine equation) instead of the canonical variational transition state theory leads to excellent agreement between the in-water-computed activation energies (Δ EwM≠) and the corresponding Δ Eexp≠ values for the SN2 mechanism, but far beyond the limit of error for the SN1 process. The validity of the Marcus theory for the studied SN1 and SN2 reactions is ensured by the fact that both reactions can be described as SET processes. On the other hand, apparently compelling evidence against the SN2 mechanism, such as 13C KIEs and experimental observation of N2 scrambling, are also discussed and alternative explanations are proposed. [ABSTRACT FROM AUTHOR]

Published
2013
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22. Solvent and Stereoelectronic Effects on the Solvolysis Rates of Oxaspirocyclopropanated 1-Norbornyl Triflates and Related Bridgehead Derivatives.

Author

García MartInez, Antonio, de la Moya Cerero, Santiago, Teso Vilar, Enrique, García Fraile, Amelia, Lora Maroto, Beatriz, and Díaz Morillo, Cristina

Subjects
*SOLVENTS, *CYCLOPROPANE, *CYCLOALKANES, *STEREOCHEMISTRY, *SOLVOLYSIS
Abstract

The study of the stereochemical outcome of the solvolysis of oxaspirocyclopropanated 1-norbornyl triflates is highly interesting since these reactions do not lead to the usual retention or fragmentation products but only synthetically interesting rearranged products are enantiospecifically formed. There is no correlation between the experimental solvolysis rates (In k) and the B3LYP/6-31G(d)-computed ionization energies (ΔE) of the corresponding bridgehead hydrocarbons in gas phase. However, this work demonstrates the existence of a fair linear correlation between the experimental reaction rates and the PCM//B3LYP/6-31G(d)-computed free ionization energies in solution (ΔG). This theoretically relevant result reveals that the reason for the lack of linearity in gas phase is not the rearrangement of the intermediate carbocations but unspecific solvent effects on the solvolysis rates, accounted for by the PCM model. [ABSTRACT FROM AUTHOR]

Published
2008
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50. Different influence of polyoxygenation on the catalytic activity of amido- versus amino-isoborneols.

Author

Sánchez-Carnerero, Esther M., de las Casas Engel, Tomás, Maroto, Beatriz Lora, and de la Moya Cerero, Santiago

Subjects
*OXYGENATION (Chemistry), *CATALYTIC activity, *AMINO compounds, *BORNEOLS, *DIETHYLZINC, *BENZALDEHYDE, *CHELATES
Abstract

A new series of polyoxygenated amido-isoborneols has been synthesized and tested in the enantioselective addition of diethylzinc to benzaldehyde and the results compared to a series of related amino isoborneols. The observed different behavior is explained on the basis of catalytic chelates previously proposed by us. [ABSTRACT FROM AUTHOR]

Published
2011

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