Investigation of the inclusion of the herbicide metobromuron in native cyclodextrins by powder X-ray diffraction and isothermal titration calorimetry

Vincent J Smith; Natalia M Rougier; Rita H de Rossi; Mino R Caira; Elba I Buján; Mariana A Fernández; Susan A Bourne

doi:10.1016/j.carres.2009.08.036

Investigation of the inclusion of the herbicide metobromuron in native cyclodextrins by powder X-ray diffraction and isothermal titration calorimetry

Carbohydr Res. 2009 Nov 23;344(17):2388-93. doi: 10.1016/j.carres.2009.08.036. Epub 2009 Sep 2.

Authors

Vincent J Smith¹, Natalia M Rougier, Rita H de Rossi, Mino R Caira, Elba I Buján, Mariana A Fernández, Susan A Bourne

Affiliation

¹ Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.

PMID: 19800052
DOI: 10.1016/j.carres.2009.08.036

Abstract

We report the formation of inclusion complexes between the phenylurea herbicide metobromuron [3-(p-bromophenyl)-1-methoxy-1-methylurea] and beta- and gamma-cyclodextrin in the solid state. Formation of crystalline inclusion complexes by the kneading method was confirmed by powder X-ray diffraction and further structural characterization using the principles of isostructurality followed. In addition, DeltaH degrees , DeltaS degrees , DeltaG degrees and the association constants (K) at 298K were determined for complex formation in solution using isothermal titration calorimetry. The magnitudes of K for the formation of 1:1 complexes between metobromuron and alpha-, beta- and gamma-CD were estimated as 598, 310 and 114, respectively.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Calorimetry
Herbicides / chemistry*
Phenylurea Compounds / chemistry*
Thermodynamics
X-Ray Diffraction
beta-Cyclodextrins / chemistry*
gamma-Cyclodextrins / chemistry*

Substances

Herbicides
Phenylurea Compounds
beta-Cyclodextrins
gamma-Cyclodextrins
metobromuron