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Advances in Physical Chemistry
Volume 2014 (2014), Article ID 710487, 12 pages
http://dx.doi.org/10.1155/2014/710487
Research Article

Controlled Release Kinetics in Hydroxy Double Salts: Effect of Host Anion Structure

1Department of Chemistry, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881, USA
2Applied Chemistry Department, National University of Science and Technology, P.O. Box AC 939, Ascot, Bulawayo, Zimbabwe

Received 10 September 2013; Revised 15 December 2013; Accepted 19 December 2013; Published 15 January 2014

Academic Editor: Jan Skov Pedersen

Copyright © 2014 Stephen Majoni and Jeanne M. Hossenlopp. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Nanodimensional layered metal hydroxides such as layered double hydroxides (LDHs) and hydroxy double salts (HDSs) can undergo anion exchange reactions releasing intercalated anions. Because of this, these metal hydroxides have found applications in controlled release delivery of bioactive species such as drugs and pesticides. In this work, isomers of hydroxycinnamate were used as model compounds to systematically explore the effects of anion structure on the rate and extent of anion release in HDSs. Following intercalation and subsequent release of the isomers, it has been demonstrated that the nature and position of substituent groups on intercalated anions have profound effects on the rate and extent of release. The extent of release was correlated with the magnitude of dipole moments while the rate of reaction showed strong dependence on the extent of hydrogen bonding within the layers. The orthoisomer showed a more sustained and complete release as compared to the other isomers.