New Low Bandgap Compounds Comprised of Pyromellitic Diimide and Imine Units

New bisimide derivatives, low molecular compounds with π-π* conjugated system consisting of a pyromellitic diimide core and imine linkages were synthesized by Schiff bases reactions, the studied compounds were prepared from N,N'-bis amino pyromellitic diimide which was condensed with different derivatives of aldehydes, the materials show a high melting point and some above ۳۰۰ ◦C depended intramolecular attractive and the Vander Waals attraction between various substituent groups. The optical properties of the prepared compounds were investigated by UV–vis measurement. The prepared compounds showed the highest intensity with maximum absorbance at ۲۴۳-۹۰۸ nm. In all studied molecules, the electrochemically estimated theoretical HOMO level is in the range of -۷.۵۱۵ to -۷۳۲۰ eV, whereas the LUMO level is close to ۷.۲۱۹ eV and -۵.۸۸۹ eV. The estimated compounds exhibited low electrochemical band gap (<۲ eV).

Keywords:

diimide , pyormellitic diimide , Electrochemistry energy gap