A Donor–Acceptor–Donor Structured Organic Conductor with S···S Chalcogen Bonding

A novel thiophene derivative 7,9-di(thiophen-2-yl)-8H-cyclopenta[a]acenaphthylen-8-one (DTCPA) is shown to exhibit high electrical conductivity (1.97 × 10–2 ± 0.0018 S/cm at RT) in the crystalline state. The material shows two orders of increase in conductivity from normal solid to single crystalline state. The crystal structure has S···S chalcogen bonding, C–H···O hydrogen bonding, and π···π stacking as the major intermolecular interactions. The nature and strength of the S···S interactions in this structure have been evaluated by theoretical charge density analysis, and its contribution to the crystal packing quantified by Hirshfeld surface analysis. Further, thermal and morphological characterizations have been carried out, and the second harmonic generation (SHG) efficiency has been measured using the Kurtz–Perry method.