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Thermodynamics of the complexation of mono- and bis-cyclodextrin derivatives with a polarity sensitive probe: Fluorescence, Induced Circular Dichroism and molecular modelling

Paper ID Volume ID Publish Year Pages File Format Full-Text
28311 44069 2012 11 PDF Available
Title
Thermodynamics of the complexation of mono- and bis-cyclodextrin derivatives with a polarity sensitive probe: Fluorescence, Induced Circular Dichroism and molecular modelling
Abstract

Steady-state, time-resolved fluorescence, Induced Circular Dichroism (ICD), Molecular Mechanics and Molecular Dynamics techniques have been employed in the study of the complexation of dimethyl 2,6-naphthalenedicarboxylate (DMN), a fluorescent probe, with mono- and bisβCD derivatives whose appended group, or βCD spacer, contain the 1,3-diphenoxy moiety (OB), i.e., 6[4-((3-(prop-2-ynyloxy)phenoxy)methyl]-1H-1,2,3-triazol-1-yl]6-deoxy-βCD (mβCD) and 1,3-bis((1-(6′-βCD-6′-yl)-1H-1,2,3-triazol-4-yl)methoxy)benzene (bβCD). The study also considers complexation with the native βCD partner. The DMN emission spectrum shows two overlapping electronic bands whose ratio of intensities, R, is very sensitive to the polarity of the medium surrounding it. The stoichiometry, the formation constants of the complexes and the ΔH and ΔS parameters upon inclusion were obtained from the change in R and weighted average lifetime, 〈τ〉, with CD concentration and temperature. DMN forms 1:1 and 2:1 stoichiometry complexes with bβCD, but does not with mβCD. Molecular modelling was also used to emulate the complexation processes in the presence of water. The 1:1 and 2:1 DMN/bβCD complex structures agree with the signs of enthalpy and entropy changes. Quenching, R at infinite bβCD concentration, fluorescence depolarization measurements and ICD spectra also support the proposed structures. Inclusion is mostly dominated by van der Waals interactions.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Complexation of mono- and bisβCD with a polarity sensitive probe. ► Fluorescence and Induced Circular Dichroism experiments were carried out. ► Stoichiometry, stability constants and ΔH0 and ΔS0 were obtained. ► Molecular modelling simulations were performed to simulate the processes.

Keywords
Cyclodextrins; Fluorescence; Circular dichroism; Molecular Mechanics; Molecular Dynamics; 2,6-Methyl naphthalenecarboxylate
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Thermodynamics of the complexation of mono- and bis-cyclodextrin derivatives with a polarity sensitive probe: Fluorescence, Induced Circular Dichroism and molecular modelling
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 237, 1 June 2012, Pages 38–48
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us