Alvariza C, Usero R, Mendicuti F. Binding of dimethyl 2,3-naphthalenedicarboxylate with alpha-, beta- and gamma-cyclodextrins in aqueous solution.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007;
67:420-9. [PMID:
16965929 DOI:
10.1016/j.saa.2006.07.039]
[Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Accepted: 07/24/2006] [Indexed: 05/11/2023]
Abstract
Fluorescence has been used to investigate the complexes of 2,3-dimethyl naphthalenedicarboxylate with naturally occurring alpha-, beta- and gamma-cyclodextrins. Emission spectra upon excitation of the naphthoate group show two peaks whose ratio of intensities R is the sensitive to the medium polarity. The change of R with cyclodextrin concentration and temperature allows us to obtain the stoichiometry, the formation constants and the changes of enthalpy and entropy upon inclusion. Complexes show 1:1 stoichiometry. R extrapolated at [CD]-->infinity and the analysis of quenching and polarization measurements, as well as, molecular mechanics calculations in the presence of water, permit us to explain the geometry of the complexes, the possible location of the guest in conformity with thermodynamics parameters and the forces responsible for the complexation.
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