Theoretical and experimental study of model oligothiophenes containing 1-methylene-2-(perfluorophenyl)hydrazine terminal unit

• The B3LYP study of oligothiophenes terminated by 1-methylene-2-(perfluorophenyl)hydrazine.
• The synthetic scheme for the preparation of this molecular series is suggested.
• Three novel molecules were prepared and characterized.
• The π-stacking dimer structures were investigated experimentally.

The electronic structure, molecular orbital energy diagrams, spectroscopic properties, vertical and adiabatic ionisation potentials of model oligothiophenes (FThn) terminated by the 1-methylene-2-(perfluorophenyl)hydrazine unit are theoretically evaluated. In this respect, three novel molecules containing thiophene and bithiophene fragments were synthesized and characterized by optical measurements. The counterpoise corrected B3LYP-D calculations of π-stacking dimers and the experimental X-ray structure analysis showed that the 1-methylene-2-(perfluorophenyl)hydrazine terminal unit supports the presence of intermolecular hydrogen bonds and the closest intermolecular interactions. For the investigated model series, the obtained results indicate the hyperchromic shift in UV–vis absorption, lower HOMO-LUMO gaps and ionisation energies comparing to the non-substituted oligothiophenes representing the typical electrical p-type semiconducting organic materials.

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