Polymorphism and migratory chiral resulotion of the free base of venlafaxine. A remarkable topotactical solid state transition from a racemate to a racemic conglomerate

Autor:	W. W. J. Elffrink, P. Bennema, Elias Vlieg, Rolf Keltjens, E.R.H. van Eck, Arno P. M. Kentgens, R. de Gelder, M. A. Deij, Jan M. M. Smits, J. Th. H. van Eupen, H. Meekes
Rok vydání:	2008
Předmět:	Phase transition Chemistry Stereochemistry Molecular Materials Stacking Free base General Chemistry Crystal structure Solid State Chemistry Condensed Matter Physics Solid State NMR Chiral resolution Crystallography Polymorphism (materials science) Melting point General Materials Science Enantiomer
Zdroj:	Crystal Growth & Design, 8, 71-79 Crystal Growth & Design, 8, 1, pp. 71-79
ISSN:	1528-7483
Popis:	The unique behavior of the active pharmaceutical ingredient Venlafaxine free base, used as an antidepressant, with respect to polymorphism and chiral resolution is reported. Using several complementary techniques, three crystal structures of Venlafaxine were identified and isolated. All three structures are composed of virtually identical enantiomeric pure layers with different stacking modes. In the crystal structure with the highest melting point, the enantiomeric separation is complete, leading to a racemic conglomerate. The conglomerate can be grown from solution or via a solid–solid phase transition of the lowest melting racemic compound. Remarkably, the crystal shape is conserved during the transition. The corresponding chiral resolution is achieved via a local melting process, allowing for a long-range migration of the molecules between layers.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::dc527abcd37ffe0c10dc0aedf67003a4 http://hdl.handle.net/2066/72059 Zobrazit plný text záznamu