Crystal structure and optical properties of fused-ring chalcone (E)-3-(anthracen-9-yl)-1-(4-nitro-phen-yl)prop-2-en-1-one

The title compound, C23H15NO3, adopts an s-cis conformation with respect to the ethyl-ene C=C and carbonyl C=O double bonds in the enone unit. The mol-ecule is significantly twisted with a dihedral angle of 48.63 (14)° between the anthracene ring system and the benzene ring. In the crystal, mol-ecules are linked into inversion dimers with an R 2 2(10) graph-set motif via pairs of C-H⋯O hydrogen bonds. The inter-molecular inter-actions were analysed and qu-anti-fied by Hirshfeld surface analysis. The mol-ecular structure was optimized and a small HOMO-LUMO energy gap of 2.55 eV was obtained using the DFT method at the B3LYP/6-311 G++(d,p) level of theory. This value is in close agreement with the experimental value of 2.52 eV obtained from the UV-vis analysis. The crystal used was a two-component merohedral twin with a refined ratio of 0.1996 (16):0.8004 (16).