Temperature effect on the vibrational dynamics of cyclodextrin inclusion complexes: investigation by FTIR-ATR
Vincenza Crupi1, Domenico Majolino, Valentina Venuti
1Dipartimento di Fisica, Università degli Studi di Messina, CNISM, UdR Messina, C. da Papardo, S. ta Sperone 31, P.O. Box 55, 98166 S. Agata, Messina, Italy.
Abstract:
The vibrational dynamics of solid inclusion complexes of the nonsteroidal anti-inflammatory drug Ibuprofen (IBP) with beta-cyclodextrin (beta-CD) and methyl-beta-cyclodextrin (Me-beta-CD) has been investigated by using attenuated total reflection-Fourier transform infrared FTIR-ATR spectroscopy, in order to monitor the changes induced, as a consequence of complexation, on the vibrational spectrum of IBP, in the wavenumber range 600-4000 cm(-1). Quantum chemical calculations were performed on monomeric and dimeric structures of IBP, derived from symmetric hydrogen bonding of the two carboxylic groups, in order to unambiguously assign some characteristic IR bands in the IBP spectrum. The evolution in temperature from 250 to 340 K of the C horizontal lineO stretching vibration, described by a best-fit procedure, allowed us to extract the thermodynamic parameter DeltaH associated to the binding of IBP with betaCDs in the solid phase. By comparing these results, Me-beta-CD has been shown to be the most effective carrier for IBP.
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
IR Spectroscopy: Molecular Vibration Overview
Stretching vibrations are vibrational motions that occur along the bond line, changing the bond length or distance between two bonded atoms. They are further distinguished as symmetric or asymmetric. In symmetric stretching, the...
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
According to Hooke's law, the vibrational frequency is directly proportional to the...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
IR and UV–Vis Spectroscopy of Aldehydes and Ketones
IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations


