Structure of a Cyclodextrin Functionalized Anionic Clay: XRD Analysis, Spectroscopy, and Computer Simulations

Mohanambe, L and Vasudevan, S (2005) Structure of a Cyclodextrin Functionalized Anionic Clay: XRD Analysis, Spectroscopy, and Computer Simulations. In: Langmuir, 21 (23). pp. 10735-10742.

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Abstract

Carboxy-methyl \beta -cyclodextrin (CMCD) cavities have been intercalated within the galleries of anionic clay, Mg-Al layered double hydroxide (LDH). The cyclodextrin functionalized LDH has been reported to adsorb neutral and nonpolar guest molecules. X-ray diffraction, IR, and Raman vibrational spectroscopy and $^1^3C$ CPMAS NMR have been used to characterize the confined CMCD molecules, whereas molecular dynamics simulations have been used to probe the interlayer arrangement and orientation of the intercalated species. Spectroscopic measurements as well as MD simulations show that there is no significant change in the geometry of the CMCD cavity on intercalation. Within the galleries of the anionic clay, the CMCD anions are arranged as bilayers with the carboxy methyl substituents, located at the narrower opening of the bucket-like cyclodextrin toroid, anchored to the LDH sheet. This arrangement leaves the wider opening of the CMCD anion facing away from the layers allowing the interior of the cyclodextrin cavity to be accessible to guest molecules. Finally, the hydrophobicity of the anchored cyclodextrin cavity has been characterized using fluorescence from pyrene included within it.

Item Type:	Journal Article
Publication:	Langmuir
Publisher:	American Chemical Society
Additional Information:	The Copyright belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	21 Feb 2006
Last Modified:	19 Sep 2010 04:23
URI:	http://eprints.iisc.ac.in/id/eprint/5522

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