title: Absolute Configuration Assignment of Chiral Resorcin[4]arenes from ECD Spectra.
abstract: Racemates of five chiral resorcin[4]arenes, four tetra-O-substituted and one hepta-O-substituted, have been resolved by enantioselective HPLC, and their ECD spectra have been recorded online by stopped-flow measurements. The absolute configuration has been assigned by comparison of the experimental ECD spectra with DFT and semiempirical calculations. For the four tetra-O-substituted resorcin[4]arenes, the ECD exciton couplet at longer wavelength depends on the chirality induced in the arene scaffold by the substituents rather than on the precise nature of the substituents themselves. Accordingly, the exciton chirality model with excitons localized on the arene scaffold, here generalized to Cnsymmetry, accurately describes the relationship between stereochemistry and chiroptical properties for this couplet, while its application at shorter wavelengths is unsafe. For the significantly larger hepta-O-substituted system the assignment particularly benefits from the use of the semiempirical ZINDO method.
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Gerardo
authors.initials: G
authors.lastname: Concilio
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Talotta
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Carmine
authors.initials: C
authors.lastname: Gaeta
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Placido
authors.initials: P
authors.lastname: Neri
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Guglielmo
authors.identifier: 0000-0001-5268-940X
authors.initials: G
authors.lastname: Monaco
authors.affiliation: Department of Chemistry and Biology "A. Zambelli", University of Salerno , Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Zanasi
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna , Via Belmeloro, 6, Bologna 40126, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Tedesco
authors.affiliation: Department of Pharmacy and Biotechnology, University of Bologna , Via Belmeloro, 6, Bologna 40126, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Bertucci