title: Quantum mechanical calculations of conformationally relevant 1H and 13C NMR chemical shifts of N-, O-, and S-substituted calixarene systems.
abstract: QM GIAO calculations of (13)C and (1)H chemical shift values of the ArCH(2)Ar group in N-, O-, and S-substituted calixarene systems were performed with a hybrid DFT functional MPW1PW91 and 6-31G(d,p) basis set. A good reproduction of experimental data was obtained for some representative calixarenes and for a series of simplified calixarene models. This allowed the derivation of chemical shift surfaces versus phi and chi dihedral angles. The applicability of chemical shift surfaces in the study of calixarene conformational features is illustrated.
authors.affiliation: Dipartimento di Scienze Farmaceutiche, Università di Salerno, Via Ponte don Melillo, 84084 Fisciano SA, Italy. bifulco@unisa.it
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Bifulco
authors.forename: Raffaele
authors.initials: R
authors.lastname: Riccio
authors.forename: Carmine
authors.initials: C
authors.lastname: Gaeta
authors.forename: Placido
authors.initials: P
authors.lastname: Neri
mesh_terms: D001128:Argon / Q000737:chemistry; D047250:Calixarenes / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008968:Molecular Conformation; D015394:Molecular Structure; D014961:X-Ray Diffraction
chemical_list: D047250:Calixarenes; D001128:Argon