title: Regarding the torsional flexibility of the dihydrolipoic acid's pharmacophore: 1,3-propanedithiol.
abstract: The conformational space of antioxidant dihydrolipoic acid has been explored through the investigation of its pharmacophore, 1,3-propanedithiol. Five of the possible 25 non-equivalent isomers (namely: gGGg', gGGg, g'AGg, gAGg and g'AGg') were observed in the 59.6-74.4 GHz frequency region using free-jet absorption rotational spectroscopy. Furthermore, for three of them, the34S mono-substituted isotopologues were also detected in natural abundance. Theoretical simulations show that the balance of steric and electronic intramolecular interactions arises on a shallow conformational potential energy surface and suggest that in polar solvents the flexibility of the dithiol chain is greater than that in the isolated phase.
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy. assimo.maris@unibo.it.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Vigorito
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy. assimo.maris@unibo.it.
authors.forename: Camilla
authors.initials: C
authors.lastname: Calabrese
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy. assimo.maris@unibo.it.
authors.forename: Ettore
authors.initials: E
authors.lastname: Paltanin
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy. assimo.maris@unibo.it.
authors.forename: Sonia
authors.initials: S
authors.lastname: Melandri
authors.affiliation: Dipartimento di Chimica G. Ciamician, Università degli Studi di Bologna, Via Selmi 2, 40126 Bologna, Italy. assimo.maris@unibo.it.
authors.forename: Assimo
authors.identifier: http://orcid.org/0000-0003-2644-0023
authors.initials: A
authors.lastname: Maris