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ChemRxiv_Contorted_Anthradithiophene_Plunkett_09-09-18.pdf (1.75 MB)
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Cyclopentannulation and Cyclodehydrogenation of Isomerically Pure 5,11-Dibromo-Anthradithiophenes Leading to Contorted Aromatics

preprint
submitted on 09.09.2018 and posted on 10.09.2018 by Sambasiva Bheemireddy, Waseem A. Hussain, Ain Uddin, Yachu Du, Matthew Hautzinger, Paul Kevorkian, Frankie Petrie, Kyle Plunkett
Isomerically pure 5,11-dibromo-2,8-dihexylanthra[2,3-b:7,6-b']dithiophene, a brominated analog of anthracenedithiophene (ADT), was prepared and utilized for a palladium catalyzed cyclopentannulation reaction with 3,3’-dimethoxyphenylacetylene. The resulting cyclopentannulated-ADT (CP-ADT) was found to be more photo-oxidatively stable than isoelectronic CP-pentacene analogs previously prepared. In addition, the CP-ADT was able to undergo an additional Scholl cyclodehydrogenation reaction to create a contorted aromatic, an incapable feat for previous CP-pentacene analogs. The resulting compound, 4-dihexyl-5,10,17,22-tetramethoxytetrabenzo[4,5:6,7:11,12:13,14]rubiceno[2,3-b:10,9-b']dithiophene, was significantly contorted out of planarity owing to four [5]helicene-like arrangements. The density functional theory (DFT) energy minimized structures suggests splay angles of 41.80 and 40.90 for the cove regions, which are significantly larger than previously published anthracene cyclopentannulated analogs. The contorted aromatic possessed a moderately low optical gap (1.50 eV) and relatively low Lowest Occupied Molecular Orbital energy (-3.70 eV).

Funding

NSF CHE-1352431, DMR-1461255, and DMR-1757954

History

Email Address of Submitting Author

kplunkett@chem.siu.edu

Institution

Southern Illinois University

Country

United States of America

ORCID For Submitting Author

0000-0002-5691-7876

Declaration of Conflict of Interest

No conflict of interest.

Version Notes

Pre-journal submission

Exports