Mañana, JUEVES, 24 DE ABRIL, el sistema se apagará debido a tareas habituales de mantenimiento a partir de las 9 de la mañana. Lamentamos las molestias.
Cations brought together by hydrogen bonds: The protonated pyridine-boronic acid dimer explained
Entity
UAM. Departamento de QuímicaPublisher
The Royal Society of ChemistryDate
2019-02-18Citation
10.1039/c8cp07542e
Physical Chemistry Chemical Physics 21.10 (2019): 5796-5802
ISSN
1463-9076 (print); 1463-9084 (online)DOI
10.1039/c8cp07542eFunded by
This work was carried out with financial support from the Ministerio de Economía, Industria y Competitividad (Projects No. CTQ2015-63997-C2-2-P, CTQ2014-57393-C2-1-P and CTQ2017-85821-R FEDER funds) and Comunidad Autónoma de Madrid (S2013/MIT2841, Fotocarbon)Project
Gobierno de España. CTQ2015-63997-C2-2-P; Gobierno de España. CTQ2014-57393-C2-1-P; Gobierno de España. CTQ2017-85821-R; Comunidad de Madrid. S2013/MIT-2841/FOTOCARBONEditor's Version
https://doi.org/10.1039/C8CP07542ESubjects
Chemical bonds; Hydrogen bonding; Hydrogen bonds; QuímicaRights
© 2019 the Owner SocietiesAbstract
According to the Cambridge Structural Database, protonated pyridine-boronic acid dimers exist in the solid phase, apparently defying repulsive coulombic forces. In order to understand why these cation-cation systems are stable, we carried out M06-2X/6-311++G(3df,2pd) electronic structure calculations and used a set of computational tools (energy partitioning, topology of the electron density and electric field maps). The behavior of the charged dimers was compared with the corresponding neutral systems, and the effect of counterions (Br - and BF 4- ) and the solvent (PCM model) on the binding energies has been considered. In the gas-phase, the charged dimers present positive binding energies but are local minima, with a barrier (16-19 kJ mol -1 ) preventing dissociation. Once the environment is included via solvent effects or counterions, the binding energies become negative; remarkably, the strength of the interaction is very similar in both neutral and charged systems when a polar solvent is considered. Essentially, all methods used evidence that the intermolecular region where the HBs take place is very similar for both neutral and charged dimers. The energy partitioning explains that repulsion and electrostatic terms are compensated by the desolvation and exchange terms in polar solvents, thus giving stability to the charged dimer
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Google Scholar:Iribarren, Íñigo
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Montero-Campillo, M. Merced
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Alkorta, Ibon
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Elguero, José
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Quiñonero, David
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