Phenyl-capped cyclopenta[c]chalcogenophenes: Synthesis, crystal structures, electrochemistry and theoretical insights

Two new phenyl capped cyclopenta[c]chalcogenophenes (PhCPTPh and PhCPSPh) were synthesized by zirconocene mediated coupling and characterized by single crystal X-ray diffraction (SCXRD). Replacement of sulfur by selenium destabilized the HOMO level and increased the structural rigidity. The crystal structures of both the compounds were found to be nearly planar. PhCPSPh, though isostructural with PhCPTPh, packed in a very-ordered and specific pattern by Se⋯π interactions between two neighboring molecules. Hirshfeld surface analysis supported the crystal structure study. Theoretical calculations exhibited very close reorganization energies of 0.23 and 0.22 eV for PhCPTPh and PhCPSPh, respectively.