Stabilizing Pentacene By Cyclopentannulation. Issue 52 (19th November 2015)

• Record Type: Journal Article
• Authors: Bheemireddy, Sambasiva R.; Ubaldo, Pamela C.; Rose, Peter W.; Finke, Aaron D.; Zhuang, Junpeng; Wang, Lichang; Plunkett, Kyle N.
• Is Part Of: Angewandte Chemie international edition. Volume 54:Issue 52(2015)
• Page Start: 15762
• Page End: 15766
• Publication Date: 2015-11-19
• Subjects: acenes -- conjugation -- organic electronics -- palladium -- polycyclic aromatic hydrocarbons; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201508650
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: A new class of stabilized pentacene derivatives with externally fused five‐membered rings are prepared by means of a key palladium‐catalyzed cyclopentannulation step. The target compounds are synthesized by chemical manipulation of a partially saturated 6, 13‐dibromopentacene precursor that can be fully aromatized in a final step through a DDQ‐mediated dehydrogenation reaction (DDQ=2, 3‐dichloro‐5, 6‐dicyano‐1, 4‐benzoquinone). The new 1, 2, 8, 9‐tetraaryldicyclopenta[fg, qr]pentacene derivatives have narrow energy gaps of circa 1.2 eV and behave as strong electron acceptors with lowest unoccupied molecular orbital energies between −3.81 and −3.90 eV. Photodegradation studies reveal the new compounds are more photostable than 6, 13‐bis(triisopropylsilylethynyl)pentacene (TIPS‐pentacene). Abstract : Five in a row : A palladium‐catalyzed cyclopentannulation followed by a DDQ‐mediated dehydrogenation converts a partially hydrogenated pentacene precursor into stabilized pentacenes. These pentacene derivatives are excellent electron acceptors and have small energy gaps. DDQ=2, 3‐dichloro‐5, 6‐dicyano‐1, 4‐benzoquinone.