title: Solvent Effects on the Monomer/Hydrogen-Bonded Dimer Equilibrium in Carboxylic Acids: (+)-(S)-Ketopinic Acid as a Case Study.
abstract: The hydrogen-bond-assisted self-association process of a chiral semirigid carboxylic acid, namely, (+)-(S)-ketopinic acid, has been studied. The multiconformational monomer/dimer equilibrium has been evaluated by means of a concentration-dependent FTIR study that enabled the experimental equilibrium constants of the dimer formation reaction (Kdim ) to be determined in two solvents of different polarity. In CDCl3 , dimeric forms predominate, even in diluted solutions (KdimCF =5.074), whereas in CD3 CN the self-association process is hindered and monomers are always the main species, irrespective of solute concentration (KdimAN =0.194). The reliability of the dimerization constants and the derived mono- and dimeric experimental fractions have been proven by means of accurate matching between the experimental vibrational circular dichroism spectra of the species and the theoretical spectra generated by considering the simultaneous weighted contributions of the concomitant monomers and dimers.
authors.affiliation: Department of Physical and Analytical Chemistry, University of Jaén, 23071, Jaén, Spain.|Department of Chemistry, University of Antwerp, Groenenborgerlaan, 171, 2020, Antwerp, Belgium.
authors.forename: Pilar Gema
authors.identifier: http://orcid.org/0000-0002-9705-4528
authors.initials: PG
authors.lastname: Rodríguez Ortega
authors.affiliation: Department of Physical and Analytical Chemistry, University of Jaén, 23071, Jaén, Spain. mmontejo@ujaen.es.
authors.forename: Manuel
authors.identifier: http://orcid.org/0000-0002-8296-4078
authors.initials: M
authors.lastname: Montejo Gámez
authors.affiliation: Department of Physical and Analytical Chemistry, University of Jaén, 23071, Jaén, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Márquez López
authors.affiliation: Department of Physical and Analytical Chemistry, University of Jaén, 23071, Jaén, Spain.
authors.forename: Juan Jesús
authors.initials: JJ
authors.lastname: López González
keywords: carboxylic acids; crystal growth; density functional calculations; hydrogen bonding; self-association