Syntheses and calculation of(E)-4-chloro-4’-ethoxystilbeneand(E)-4, 4’-dichlorostilbene

(E)-4-chloro-4’-ethoxystilbene(2a)and(E)-4, 4’-dichlorostilbene(2b)were synthesized by the Witting-Horner reaction. The crystals of 2a and 2b were prepared through solvent evaporation and characterized by the single-crystal X-ray diffraction. Molecular structure analysis confirms the E-configuration of CC bond. The crystal of 2a reveals an orthorhombic and space group Pna21 structure while 2b shows a monoclinic and space group P21/c structure. The electronic structures of 2a and 2b were optimized at B3LYP/6-311++G(d, p)level. The Hirshfeld surface and fingerprint plot indicate close O—H and Cl—H contacts and π—π stacking in 2a and 2b. Molecular electrostatic potential shows that the O and Cl atoms of 2a and Cl atoms of 2b have the minimum energies and they are more likely to be attacked by electrophiles in reaction. Frontier molecular orbitals analysis demonstrates that the ΔELUMO-HOMO of 2a and 2b are 3.85 and 3.91 eV, respectively.