Alternating oligo(o, p-phenylenes) via ruthenium catalyzed diol–diene benzannulation: orthogonality to cross-coupling enables de novo nanographene and PAH construction. Issue 40 (30th August 2018)

• Record Type: Journal Article
• Authors: Kasun, Zachary A.; Sato, Hiroki; Nie, Jing; Mori, Yasuyuki; Bender, Jon A.; Roberts, Sean T.; Krische, Michael J.
• Is Part Of: Chemical science. Volume 9:Issue 40(2018)
• Page Start: 7866
• Page End: 7873
• Publication Date: 2018-08-30
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c8sc03236j
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : Ruthenium(0) catalyzed diol–diene benzannulation enables formation of p -bromo-terminated alternating oligo( o, p -phenylenes) and, therefrom, diverse PAH materials. Abstract : Ruthenium(0) catalyzed diol–diene benzannulation is applied to the conversion of oligo( p -phenylene vinylenes)2a–c, 5 and6 to alternating oligo( o, p -phenylenes)10a–c, 11–13 . Orthogonality with respect to conventional palladium catalyzed biaryl cross-coupling permits construction of p -bromo-terminated alternating oligo( o, p -phenylenes)10b, 11–13, which can be engaged in Suzuki cross-coupling and Scholl oxidation. In this way, structurally homogeneous nanographenes16a–f are prepared. Nanographene16a, which incorporates 14 fused benzene rings, was characterized by single crystal X-ray diffraction. In a similar fashion, p -bromo-terminated oligo( p -phenylene ethane diol)9, which contains a 1, 3, 5-trisubstituted benzene core, is converted to the soluble, structurally homogeneous hexa- peri -hexabenzocoronene18 . A benzothiophene-terminated pentamer10c was prepared and subjected to Scholl oxidation to furnish the helical bis(benzothiophene)-fused picene derivative14 . The steady-state absorption and emission properties of nanographenes14, 16a, b, d, e, h and18 were characterized. These studies illustrate how orthogonality of ruthenium(0) catalyzed diol–diene benzannulation with respect to classical biaryl cross-coupling streamlines oligophenylene and nanographene construction.