title: Influence of Polarity and Activation Energy in Microwave-Assisted Organic Synthesis (MAOS).
abstract: The aim of this work was to determine the parameters that have decisive roles in microwave-assisted reactions and to develop a model, using computational chemistry, to predict a priori the type of reactions that can be improved under microwaves. For this purpose, a computational study was carried out on a variety of reactions, which have been reported to be improved under microwave irradiation. This comprises six types of reactions. The outcomes obtained in this study indicate that the most influential parameters are activation energy, enthalpy, and the polarity of all the species that participate. In addition to this, in most cases, slower reacting systems observe a much greater improvement under microwave irradiation. Furthermore, for these reactions, the presence of a polar component in the reaction (solvent, reagent, susceptor, etc.) is necessary for strong coupling with the electromagnetic radiation. We also quantified that an activation energy of 20-30 kcal mol(-1) and a polarity (μ) between 7-20 D of the species involved in the process is required to obtain significant improvements under microwave irradiation.
authors.affiliation: Departamento de Química Orgánica, Universidad de Castilla-La Mancha, Facultad de Ciencias y Tecnologías Químicas 13071, Ciudad Real, Spain.
authors.forename: Antonio M
authors.initials: AM
authors.lastname: Rodríguez
authors.affiliation: Departamento de Química Orgánica, Universidad de Castilla-La Mancha, Facultad de Ciencias y Tecnologías Químicas 13071, Ciudad Real, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Prieto
authors.affiliation: Departamento de Química Orgánica, Universidad de Castilla-La Mancha, Facultad de Ciencias y Tecnologías Químicas 13071, Ciudad Real, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: de la Hoz
authors.affiliation: Departamento de Química Orgánica, Universidad de Castilla-La Mancha, Facultad de Ciencias y Tecnologías Químicas 13071, Ciudad Real, Spain.
authors.forename: Ángel
authors.initials: Á
authors.lastname: Díaz-Ortiz
authors.affiliation: Departamento de Química Orgánica, Universidad de Castilla-La Mancha, Facultad de Ciencias y Tecnologías Químicas 13071, Ciudad Real, Spain.
authors.forename: D Raúl
authors.initials: DR
authors.lastname: Martín
authors.affiliation: Departamento de Química Orgánica, Instituto de Síntesis Química y Catálisis Homogénea, CSIC-Universidad de Zaragoza C/. Pedro Cerbuna, 12, 50009, Zaragoza, Spain.
authors.forename: José I
authors.initials: JI
authors.lastname: García
keywords: activation energy; computational chemistry; microwave irradiation; organic synthesis; polarity