On-surface synthesis of π-conjugated ladder-type polymers comprising nonbenzenoid moieties. Issue 38 (2nd July 2021)

• Record Type: Journal Article
• Authors: Urgel, José I.; Bock, Julian; Di Giovannantonio, Marco; Ruffieux, Pascal; Pignedoli, Carlo A.; Kivala, Milan; Fasel, Roman
• Is Part Of: RSC advances. Volume 11:Issue 38(2021)
• Page Start: 23437
• Page End: 23441
• Publication Date: 2021-07-02
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra03253d
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : On-surface synthesis provides a powerful approach toward the fabrication of π-conjugated ladder polymers (CLPs). The synthesis of nonbenzenoid CLPs is achieved following two activation steps, including the formation of an intermediate 1D polymer. Abstract : On-surface synthesis provides a powerful approach toward the atomically precise fabrication of π-conjugated ladder polymers (CLPs). We report herein the surface-assisted synthesis of nonbenzenoid CLPs from cyclopenta-annulated anthracene monomers on Au(111) under ultrahigh vacuum conditions. Successive thermal annealing steps reveal the dehalogenative homocoupling to yield an intermediate 1D polymer and the subsequent cyclodehydrogenation to form the fully conjugated ladder polymer. Notably, neighbouring monomers may fuse in two different ways, resulting in six- and five-membered rings, respectively. The structure and electronic properties of the reaction products have been investigated via low-temperature scanning tunneling microscopy and spectroscopy, complemented by density-functional theory calculations. Our results provide perspectives for the on-surface synthesis of nonbenzenoid CLPs with the potential to be used for organic electronic devices.