Structural, electrochemical and theoretical study of a new chalcone derivative containing 3-thiophene rings

The title chalcone, 1,3-di(thiophene-3-yl)prop-2-en-1-one (C11H8OS2) is an essentially planar molecular with its terminal thiophene rings subtending an angle of 8.9°. The crystal structure consists in the π··π stacking of molecules defining columns along [010], further linked along c by non conventional C H⋯O bonds, thus determining broad planar arrays parallel to (100). In addition, there are weak S⋯S contacts connecting these weakly interacting 2D substructures. The experimental results obtained from single crystal X-ray diffraction data and the theoretical geometry calculated by molecular mechanics are in good agreement. Electrochemical records reveal an anodic profile with an unsymmetrical irreversible peak at 1.77 V and a shoulder at 1.62 V vs SCE, a behavior interpretable as due to the oxidation of reactive sites present in the molecule. On the other hand, the electrochemical reduction shows a narrow peak at −1.58 V vs SCE, a fact attributable to the carbonyl group. Finally, the values for the energy involved in the departure/arrival of electrons from border orbitals, as calculated using DFT, is compared with experimental data from cyclic voltammetry.