Direct evidence of polyamorphism in paracetamol. Issue 47 (21st October 2015)

• Record Type: Journal Article
• Authors: Nguyen Thi, Yen; Rademann, Klaus; Emmerling, Franziska
• Is Part Of: CrystEngComm. Volume 17:Issue 47(2015)
• Page Start: 9029
• Page End: 9036
• Publication Date: 2015-10-21
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/c5ce01583a
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : Two different amorphous states were identified as structure defining precursors during the crystallization of paracetamol. Abstract : While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided.