Prev. Article Next Article Table of Contents

Article

Crystal Structure of Aspartame Anhydrate from Powder Diffraction Data. Structural Aspects of the Dehydration Process of Aspartame

Supporting Info

C. Guguta, H. Meekes, and R. de Gelder*

Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands

Crystal Growth & Design, 2006, 6 (12), pp 2686–2692

DOI: 10.1021/cg060300d

Publication Date (Web): October 25, 2006

To whom correspondence should be addressed. Mailing address: Molecular Materials, Institute for Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands. Tel: +31 (0) 24 3652842. Fax: +31 (0) 24 3553450. E-mail: R.deGelder @science.ru.nl. Web: http://www.crystallography.nl.

Abstract

Aspartame has three pseudo-polymorphic forms, two hydrates and a hemi-hydrate, for which crystal structures were determined from single-crystal diffraction data. This paper presents the crystal structure of the anhydrate, which was obtained by dehydrating the hemi-hydrate. The crystal structure of aspartame anhydrate, l-aspartyl-l-phenylalanine methyl ester, was determined from X-ray powder diffraction data. Aspartame anhydrate crystallizes in the monoclinic system with space group P2₁ and cell parameters: a = 19.4078(10) Å, b = 4.9605(2) Å, c = 15.6547(9) Å, β = 94.876(2)°, V = 1501.65(14) Å³. Final Rietveld refinement resulted in R_wp = 2.26 and a GOOF of 2.30. Comparing the hydrates of aspartame and using molecular modeling provide a complete and clear picture of the dehydration behavior of aspartame at the molecular level.