Elucidating the Polymorphism of Xanthone: A Crystallization and Characterization Study

<p>Dataset related to the publication: "Elucidating the Polymorphism of Xanthone: A Crystallization and Characterization Study". Accepted in Crystal Growth and Design on February 9th, 2024.</p> <p>Abstract: The aim of this work is to shed light on the polymorphism of xanthones, a class of oxygenated molecules well known for their bioactivity, including antioxidant,&nbsp;anticancer, and anti-inflammatory effects. Understanding the polymorphism of xanthones can enable the design of novel solid products for pharmaceutical, nutraceutical, and&nbsp;agrochemical applications. Prior to this work, two entries accounting for different space&nbsp;groups were deposited for 9-xanthone in the Cambridge Structure Database (CSD): an&nbsp;orthorhombic P212121 and a monoclinic P21 structure solved at room and low&nbsp;temperatures, respectively. However, the very high similarity between these two structures&nbsp;and the lack of clear differences in the physical properties (e.g., thermal behavior)&nbsp;suggested the possibility of the existence of only one crystal structure. In fact, the&nbsp;differences shown in the literature data might be related to the chosen operating&nbsp;parameters, as well as the instrumental resolution of the single-crystal X-ray diffraction&nbsp;experiments. In the work presented here, the ambiguity in the polymorphism of xanthone&nbsp;is investigated using thermal analysis, powder and synchrotron single-crystal XRD, and optical microscopy. Additionally, a workflow&nbsp;for the correct identification of twinned crystal structures, which can be applied to other polymorphic systems, is presented. Such&nbsp;workflow combines the collection of a large data set of high-resolution diffraction patterns using synchrotron radiation with the use&nbsp;of principal component analysis, a dimensionality reduction technique, for a quick and effective identification of phase transitions&nbsp;happening during the data collection. Crystallization experiments were designed to promote the formation of different crystal&nbsp;structures of xanthone that were recrystallized based on past literature and beyond.</p>