title: The hydrogen bonding and conformations of p-tert-butylcalix[4]arene as studied by IR spectroscopy and by DFT calculations.
abstract: IR and far IR spectra of p-tert-butylcalix[4]arene were recorded at various temperatures between 16 and 180 degrees C and spectra of solutions and crystalline solids were obtained. Ab initio density functional calculations gave vibrational frequencies and infrared intensities for four conformers: cone, partial cone, 1,2- and 1,3-alternate. Complete assignments were made for experimental IR spectra of the cone conformer. The bands characteristic for each conformation were defined. It was revealed that O--H stretching low-frequency shift Deltanu in the cone conformation exceeds Deltanu shifts for other conformers. The effect was stipulated by a cooperative interaction of cyclic hydrogen bonds. The obtained spectra-structure correlation can be used for characteristic of calixarenes conformation.
authors.affiliation: Kazan State Architect and Civil Engineering Academy, Department of Physics, 1 Zelenaya, 420043 Kazan, Russia. furer@ksaba.ru
authors.forename: V L
authors.initials: VL
authors.lastname: Furer
authors.forename: E I
authors.initials: EI
authors.lastname: Borisoglebskaya
authors.forename: V V
authors.initials: VV
authors.lastname: Zverev
authors.forename: V I
authors.initials: VI
authors.lastname: Kovalenko
mesh_terms: D047250:Calixarenes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation; D015394:Molecular Structure; D013053:Spectrophotometry; D013055:Spectrophotometry, Infrared; D014633:Valine / Q000031:analogs & derivatives* / Q000737:chemistry; D014732:Vibration
chemical_list: C434726:4-tert-butylcalix(4)arene tetravaline benzyl ester; D047250:Calixarenes; D014633:Valine