Torsional Barriers to Rotation and Planarization in Heterocyclic Oligomers of Value in Organic Electronics

• Published in: Journal of chemical theory and computation Vol. 13; no. 11; pp. 5624 - 5638
• Main Authors: Lin, Janice B, Jin, Yu, Lopez, Steven A, Druckerman, Nathaniel, Wheeler, Steven E, Houk, K. N
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14.11.2017
• Subjects: Chemical-mechanical polishing; Crystal structure; Electronic devices; Functionals; Oligomers; Organic materials; Torsion
• ISSN: 1549-9618; 1549-9626
• DOI: 10.1021/acs.jctc.7b00709

In order to understand the conformational behavior of organic components in organic electronic devices, we have computed the torsional potentials for a library of thiophene-based heterodimers. The accuracy and efficiencies of computational methods for these organic materials were benchmarked for 11 common density functionals with three Pople basis sets against a Focal Point Analysis (FPA) on a model oligothiophene 2,5-bis­(3-tetradecylthiophen-2-yl)­thieno­[3,2-b]-thiophene (BTTT) system. This study establishes a set of general trends in regards to conformational preferences, as well as planarization and rotational barriers for a library comprised of common fragments found in organic materials. These gas phase structures are compared to experimental crystal structures to determine the effect of crystal packing on geometry. Finally, we analyze the structure of hole-transporting material DERDTS-TBDT and design a new oligomer likely to be planar in the solid state.