Single crystal X-ray structures and photophysical properties of three anthracene derivatives

Abstract

Anthracene and its derivatives have attracted interest due to their planar, linearly fused three-ring systems, which play a key role in crystal engineering and supramolecular chemistry. The anthracene nucleus has a potential of forming π-π and Csingle bondH…π interactions as well as Csingle bondH…O, Csingle bondH…N, and Csingle bondH…S interactions when derivatized with a suitable functional group. Despite the potential for diverse non-covalent interactions, reports of anthracene derivatives exhibiting discrete Csingle bondH…O, Csingle bondH…N, and Csingle bondH…S interactions remain relatively limited in the literature. With this view, three different derivatives of anthracene bearing diethyl malonate (1), 1,3-propanediol (2), and thiocarbohydrazide (3) were synthesized and structurally characterized by single-crystal X-ray diffraction. Compounds 1 and 2 crystallize in a monoclinic system with P21/c space group, whereas 3 crystallizes in a monoclinic system with P21/n space group. The diethyl malonate derivative of anthracene exhibits a herringbone arrangement through π-π stacking. Compound 2 features slipped π-π stacking in addition to Csingle bondH…O and Csingle bondH…π interactions. The thiocarbohydrazone derivative of anthracene (3) shows offset π-π stacking along with Nsingle bondH…S, Csingle bondH…π, and Csingle bondH…S hydrogen bonds. Hirshfeld surface analysis and fingerprint plots reveal that H…H contacts dominate the intermolecular interactions across all three structures, with significant contributions from C…H, O…H, S…H, and N…H contacts, consistent with the observed packing motifs.