The effect of the fused-ring substituent on anthracene chalcones: crystal structural and DFT studies of 1-(anthracen-9-yl)-3-(naphthalen-2-yl)prop-2-en-1-one and 1-(anthracen-9-yl)-3-(pyren-1-yl)prop-2-en-1-one

The title chalcone compounds, C(27)H(18)O (I) and C(33)H(20)O (II), were synthesized using a Claisen–Schmidt condensation. Both compounds display an s-trans configuration of the enone moiety. The crystal structures feature inter­molecular C—H⋯O and C—H⋯π inter­actions. Quantum chemical analysis of density functional theory (DFT) with a B3LYP/6–311++G(d,p) basis set has been employed to study the structural properties of the compound. The effect of the inter­molecular inter­actions in the solid state are responsible for the differences between the experimental and theoretical optimized geometrical parameters. The small HOMO–LUMO energy gap in (I) (exp : 3.18 eV and DFT: 3.15 eV) and (II) (exp : 2.76 eV and DFT: 2.95 eV) indicates the suitability of these compounds for optoelectronic applications. The inter­molecular contacts and weak contributions to the supra­molecular stabilization are analysed using Hirshfeld surface analysis.