Recently, α-oligofurans have emerged as interesting and promising organic electronic materials that have certain advantages over α-oligothiophenes. In this work, α-oligofurans were studied computationally, and their properties were compared systematically with those of the corresponding oligothiophenes. Although the two materials share similar electronic structures, overall, this study revealed important differences between α-oligofurans and α-oligothiophenes. Twisting studies on oligofurans revealed them to be significantly more rigid than oligothiophenes in the ground state and first excited state. Neutral α-oligofurans have more quinoid character, higher frontier orbital energies, and higher HOMO-LUMO gaps than their α-oligothiophene counterparts. The theoretical results suggest that oligofurans (and subsequently polyfuran) have lower ionization potentials than the corresponding oligothiophenes (and polythiophene), which in turn predicts that oligofurans can be lightly doped more easily than oligothiophenes. Oligofuran dications (8 F2+-14 F2+) of medium-sized and longer chain lengths show a polaron-pair character, and the polycations of α-oligofurans cannot accommodate high positive charges as easily as their thiophene analogues. Organic electronic materials: Calculations reveal that, in comparison with α-oligothiophenes, α-oligofurans have a more rigid structure in the ground and excited states (see figure), a more quinoid character, higher HOMO-LUMO gaps, and undergo initial (light) doping more easily. These calculations contribute to the understanding of α-oligofurans, which were synthesized only recently, and which are now emerging as promising organic electronic materials.
- density functional calculations
- pi-conjugated materials
ASJC Scopus subject areas
- Organic Chemistry