QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds

Although parametrized Semiempirical Molecular Orbital Methods were especially designed to obtain enthalpies of formation and other related thermodynamical parameters, in some situations the predictions cannot be compared to the experimental results simply because they present serious drawbacks.There...

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Autores principales: Duchowicz, Pablo Román, Castro, Eduardo Alberto, Fernández, Francisco Marcelo, Pankratov, A. N.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2006
Materias:
Química
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/164784
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-164784
record_format dspace
spelling I19-R120-10915-1647842024-04-13T04:38:31Z http://sedici.unlp.edu.ar/handle/10915/164784 QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds Duchowicz, Pablo Román Castro, Eduardo Alberto Fernández, Francisco Marcelo Pankratov, A. N. 2006 2024-04-12T17:10:29Z en Química Although parametrized Semiempirical Molecular Orbital Methods were especially designed to obtain enthalpies of formation and other related thermodynamical parameters, in some situations the predictions cannot be compared to the experimental results simply because they present serious drawbacks.Therefore, there is room to apply a wide variety of predictive methods for estimating thermodynamical properties, such as the well-known Group Contribution Methods and the Quantitative Structure-Property Relationships. A QSPR study of 163 enthalpies of formation, 37 Gibbs free energy changes, and 40 standard entropies of elements is established for a representative set of acyclic and aromatic compounds, on the basis of fundamental concepts on molecular structure such as the count of atoms and types of chemical bonds. A recent method discovered in our group called the Replacement Method is employed here to find the best models in a pool containing 33 descriptors. An 8 parameters-model was able to correlate the heats of formation with atoms and bond types (R=0.9553, Rl-25%-o=0.8200) but with great dispersion (S=19.173 Kcal/ mol). For the case of standard entropies (R=0.9813, R l-20%-o=0.8659) and for free energies (R=0.9869, R l-20%-o=0.9000) the models obtained perform poorer than those calculated with Semiempirical Methods. A pesar de que los métodos parametrizados de Orbitales Moleculares Semiempíricos se diseñaron especialmente para obtener entalpías de formación u otros parámetros termodinámicos, en algunas situaciones las predicciones no pueden compararse con los resultados experimentales simplemente porque presentan serias anomalías. Por tanto, hay lugar para aplicar una amplia variedad de métodos predictivos para estimar propiedades termodinámicas, tales como los bien conocidos Métodos de Contribución de Grupos y las Relaciones Cuantitativas Estructura-Propiedad. Se establece un estudio QSPR para 163 entalpías de formación, 37 cambios de energía libre de Gibbs, y 40 entropías estándar a partir de elementos para un conjunto representativo de compuestos acíclicos y aromáticos, sobre la base de conceptos fundamentales de estructura molecular como lo son la cuenta de átomos y tipos de enlace químico. Se emplea un método reciente descubierto en nuestro grupo llamado Método de Reemplazo para encontrar los mejores modelos a partir de un conjunto total de 33 descriptores. Un modelo de 8 parámetros fue capaz de correlacionar los calores de formación con los átomos y tipo de enlaces (R=0,9553, Rl-25%-o=0,8200) pero con gran dispersión (S=19,173 Kcal/mol). Para el caso de entropías estándar (R=0,9813, R l-20%-o=0,8659) y para energías libres (R=0,9869, R l-20%-o=0,9000) los resultados que se obtienen resultan más pobres a los alcanzados con los Métodos Semiempíricos. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas Articulo Articulo http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf 31-45
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Química
spellingShingle Química
Duchowicz, Pablo Román
Castro, Eduardo Alberto
Fernández, Francisco Marcelo
Pankratov, A. N.
QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
topic_facet Química
description Although parametrized Semiempirical Molecular Orbital Methods were especially designed to obtain enthalpies of formation and other related thermodynamical parameters, in some situations the predictions cannot be compared to the experimental results simply because they present serious drawbacks.Therefore, there is room to apply a wide variety of predictive methods for estimating thermodynamical properties, such as the well-known Group Contribution Methods and the Quantitative Structure-Property Relationships. A QSPR study of 163 enthalpies of formation, 37 Gibbs free energy changes, and 40 standard entropies of elements is established for a representative set of acyclic and aromatic compounds, on the basis of fundamental concepts on molecular structure such as the count of atoms and types of chemical bonds. A recent method discovered in our group called the Replacement Method is employed here to find the best models in a pool containing 33 descriptors. An 8 parameters-model was able to correlate the heats of formation with atoms and bond types (R=0.9553, Rl-25%-o=0.8200) but with great dispersion (S=19.173 Kcal/ mol). For the case of standard entropies (R=0.9813, R l-20%-o=0.8659) and for free energies (R=0.9869, R l-20%-o=0.9000) the models obtained perform poorer than those calculated with Semiempirical Methods.
format Articulo
Articulo
author Duchowicz, Pablo Román
Castro, Eduardo Alberto
Fernández, Francisco Marcelo
Pankratov, A. N.
author_facet Duchowicz, Pablo Román
Castro, Eduardo Alberto
Fernández, Francisco Marcelo
Pankratov, A. N.
author_sort Duchowicz, Pablo Román
title QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
title_short QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
title_full QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
title_fullStr QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
title_full_unstemmed QSPR evaluation of thermodynamic properties of acyclic and aromatic compounds
title_sort qspr evaluation of thermodynamic properties of acyclic and aromatic compounds
publishDate 2006
url http://sedici.unlp.edu.ar/handle/10915/164784
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AT castroeduardoalberto qsprevaluationofthermodynamicpropertiesofacyclicandaromaticcompounds
AT fernandezfranciscomarcelo qsprevaluationofthermodynamicpropertiesofacyclicandaromaticcompounds
AT pankratovan qsprevaluationofthermodynamicpropertiesofacyclicandaromaticcompounds
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