NEAR-INFRARED SPECTROSCOPIC INVESTIGATION OF INCLUSION COMPLEXES BETWEEN CYCLODEXTRINS AND AROMATIC-COMPOUNDS

Citation
Mj. Politi et al., NEAR-INFRARED SPECTROSCOPIC INVESTIGATION OF INCLUSION COMPLEXES BETWEEN CYCLODEXTRINS AND AROMATIC-COMPOUNDS, Journal of physical chemistry, 99(38), 1995, pp. 14137-14141
Citations number
62
Categorie Soggetti
Chemistry Physical
ISSN journal
00223654
Volume
99
Issue
38
Year of publication
1995
Pages
14137 - 14141
Database
ISI
SICI code
0022-3654(1995)99:38<14137:NSIOIC>2.0.ZU;2-B
Abstract
Near infrared (NIR) absorption in the 900-1800 nm region has been used to characterize and measure the association constants of the inclusio n complexes between aromatic compounds (e.g., phenol, 4-chlorophenol, sodium 2-naphthalenesulfonate, and sodium 2-pyrenesulfonate) and alpha -, beta-, and gamma-cyclodextrin. It was found that the NIR method is particularly suited for this type of study because upon forming comple xes, the oscillator strengths of the C-H stretching [Delta nu = 2 (at similar to 1650 nm) and 3 (at similar to 1120 nm)] overtone bands of t he aromatic guest compounds were increased by at least 2-5-fold. The o bserved increases are rationalized in terms of the enhancement in the anharmonicity and the libration motions of the guest molecule in the C D cavity. This enhancement effect facilitates the calculation of the a ssociation constants of the inclusion complexes. As expected, the calc ulated values are in relatively good agreement with previously determi ned values.