(E)-1-(Benzo[d][1,3]dioxol-5-yl)-3-([2,2′-bithio-phen]-5-yl)prop-2-en-1-one: crystal structure, UV-Vis analysis and theoretical studies of a new π-conjugated chalcone

In the title compound, C18H12O3S2, synthesized by the Claisen-Schmidt condensation method, the essentially planar chalcone unit adopts an s-cis configuration with respect to the carbonyl group within the ethylenic bridge. In the crystal, weak C-H center dot center dot center dot pi interactions connect the molecules into zigzag chains along the b-axis direction. The molecular structure was optimized geometrically using Density Functional Theory (DFT) calculations at the B3LYP/6-311 G++(d,p) basis set level and compared with the experimental values. Molecular orbital calculations providing electron-density plots of HOMO and LUMO molecular orbitals and molecular electrostatic potentials (MEP) were also computed both with the DFT/B3LYP/6-311 G++(d, p) basis set. The experimental energy gap is 3.18 eV, whereas the theoretical HOMO-LUMO energy gap value is 2.73 eV. Hirshfeld surface analysis was used to further investigate the weak interactions present.