Cooperativity effects in a new pterostilbene/phenanthroline cocrystal

Abstract

The SCXRD structure of the natural dietary compound pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene) and phenanthroline (1,10-phenanthroline) cocrystal is reported herein. In the solid state the cocrystal forms several H-bonded and Csingle bondH···π supramolecular synthons that have been analyzed by DFT calculations, with a particular focus on the parallel face-to-face stacking of the phenanthroline rings, a relevant and quite unusual feature (antiparallel displaced mode is more common). Cooperativity effects between H-bonding and aromatic interactions have been studied to rationalize the formation of this unusual π-stacking mode and the supramolecular assemblies have been further analyzed using several computational techniques, i.e., molecular electrostatic potential (MEP) surfaces and the quantum theory of 'atom-in-molecules' (QTAIM) combined with reduced density gradient (RDG) plots.