Solution-Phase Synthesis and Isolation of An Aza-Triangulene and Its Cation in Crystalline Form

Haipeng Wei; Xudong Hou; Tingting Xu; Ya Zou; Guangwu Li; Shaofei Wu; Yanhou Geng; Jishan Wu

doi:10.1002/anie.202210386

Solution-Phase Synthesis and Isolation of An Aza-Triangulene and Its Cation in Crystalline Form

Angew Chem Int Ed Engl. 2022 Oct 4;61(40):e202210386. doi: 10.1002/anie.202210386. Epub 2022 Sep 5.

Authors

Haipeng Wei^{1

2}, Xudong Hou¹, Tingting Xu¹, Ya Zou¹, Guangwu Li¹, Shaofei Wu¹, Yanhou Geng², Jishan Wu^{1

2}

Affiliations

¹ Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore.
² Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou 350207, China.

PMID: 36000462
DOI: 10.1002/anie.202210386

Abstract

Synthesis of triangulene and its derivatives is challenging due to their intrinsic high spin nature. Herein, we report solution-phase synthesis and isolation of a nitrogen-doped triangulene (i.e., aza-triangulene) (NT) and its cation (NT⁺ ) in single-crystal form. Notably, the cation NT⁺ can be regarded as an isoelectronic structure of the corresponding all-carbon triangulene. Both NT and NT⁺ show reasonable stability due to kinetic blocking by bulky and electron-withdrawing aryl substituents, and intramolecular donor-acceptor interaction. Bond length analysis, magnetic measurements and theoretical calculations reveal that the neutral NT has a doublet ground state with a zwitterionic character, while the cation NT⁺ exhibits a triplet ground state with a singlet-triplet energy gap of +0.84 kcal mol^-1 . This study provides a rational strategy to access high-spin systems by heteroatom doping of pure π-conjugated polycyclic hydrocarbons.

Keywords: Heteroatom Doping; Polycyclic Hydrocarbon; Radical; Triangulene; Zwitterionic.

Abstract

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