Issue 13, 2019

Explaining crystallization preferences of two polyphenolic diastereoisomers by crystal structure prediction

Abstract

Despite their structural similarity, two naturally occuring polyphenols, epicatechin and catechin, display significantly distinct crystallization behaviour. Epicatechin crystallizes only as a pure compound, and appears to be monomorphic, whereas no pure crystalline form of catechin is known, but it can form a variety of solvates with polar solvents. This work aims to explain these experimentally observed differences using the results of crystal structure prediction calculations. The entire conformational space of both molecules has been included in the crystal structure prediction study, which also explored the crystal structure landscapes of the pure crystals, 1 : 1 solvates and 2 : 1 solvates. From the computational results, we were able to show that the experimental observations with regard to crystallization behavior are the result of a trade-off between intra- and intermolecular energy contributions to the total energy of a crystalline system. In the case of epicatechin, conformers with low gas phase energies are at the same time the ones able to form crystal structures with favourable intermolecular interactions. In contrast, only high energy gas phase conformers of catechin were found to be able to pack efficiently. Consequently, the unfavorable intramolecular energy contribution has to be compensated by stabilizing intermolecular interactions. The calculations for 2 : 1 and 1 : 1 methanol solvates of both molecules demonstrate that such compensation can be readily provided by solvent molecules able to form hydrogen bonds with catechin.

Graphical abstract: Explaining crystallization preferences of two polyphenolic diastereoisomers by crystal structure prediction

Supplementary files

Article information

Article type
Paper
Submitted
17 okt 2018
Accepted
27 noy 2018
First published
27 noy 2018

CrystEngComm, 2019,21, 2067-2079

Explaining crystallization preferences of two polyphenolic diastereoisomers by crystal structure prediction

M. K. Dudek and G. M. Day, CrystEngComm, 2019, 21, 2067 DOI: 10.1039/C8CE01783B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements