Increased Coplanarity and Conjugation and Lowered HOMO-LUMO Energy Differences in Benzochalogens Connected to Aromatic Substituents via Ethynyl Spacers: A DFT Study
Abstract
The simple insertion of an ethynyl spacer between aromatic substituents and benzochalogen cores significantly increases coplanarity and decreases HOMO-LUMO energy differences by up to 30% when compared to the corresponding compounds without the ethynyl spacer as determined by DFT analysis. This concept also applies for oligomers. DFT calculations on the B3LYP/6-31G* level were performed for organic semiconductors based on benzochalcogens (bibenzodithiophenes, naphthodithiophenes, bibenzodiselenophenes) bearing lateral aromatic substituents (phenyl, thienyl, naphthyl, pyrenyl). Direct attachment of these aromatic substituents to the benzochalcogen core resulted in non-coplanar geometries due to steric interactions between the core and the lateral aromatic groups. However, when utilizing an ethynyl moiety as a spacer between core and aromatic substituent, coplanarization and up to 30% reduction in HOMO-LUMO energy differences (gap energies) were achieved. This concept was also successfully extended to bibenzothiophene-based oligomers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 25, 2013
- Accession Number
- ADA577127
Entities
People
- Jianmin Shi
- Michael R. Korn
- Ron Pieper
Organizations
- University of Texas at Tyler