Covalent C-N Bond Formation through a Surface Catalyzed Thermal Cyclodehydrogenation

Ilya Piskun; Raymond Blackwell; Joaquim Jornet-Somoza; Fangzhou Zhao; Angel Rubio; Steven G Louie; Felix R Fischer

doi:10.1021/jacs.9b13507

Covalent C-N Bond Formation through a Surface Catalyzed Thermal Cyclodehydrogenation

J Am Chem Soc. 2020 Feb 26;142(8):3696-3700. doi: 10.1021/jacs.9b13507. Epub 2020 Feb 12.

Authors

Ilya Piskun¹, Raymond Blackwell¹, Joaquim Jornet-Somoza^{2

3}, Fangzhou Zhao^{4

5}, Angel Rubio^{2

3

6}, Steven G Louie^{4

5}, Felix R Fischer^{1

5

7}

Affiliations

¹ Department of Chemistry , University of California , Berkeley , California 94720 , United States.
² Nano-Bio Spectroscopy Group and ETSF , Universidad del País Vasco UPV/EHU , Avenida de Tolosa 72 , E-20018 Donostia , Spain.
³ Max Planck Institute for the Structure and Dynamics of Matter , Bldg. 99, Luruper Chaussee 149 , 22761 Hamburg , Germany.
⁴ Department of Physics , University of California , Berkeley , California 94720 , United States.
⁵ Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.
⁶ Center for Computational Quantum Physics (CCQ) , The Flatiron Institute , 162 Fifth Avenue , New York , New York 10010 , United States.
⁷ Kavli Energy NanoSciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States.

PMID: 32043869
DOI: 10.1021/jacs.9b13507

Abstract

The integration of substitutional dopants at predetermined positions along the hexagonal lattice of graphene-derived polycyclic aromatic hydrocarbons is a critical tool in the design of functional electronic materials. Here, we report the unusually mild thermally induced oxidative cyclodehydrogenation of dianthryl pyrazino[2,3-g]quinoxalines to form the four covalent C-N bonds in tetraazateranthene on Au(111) and Ag(111) surfaces. Bond-resolved scanning probe microscopy, differential conductance spectroscopy, along with first-principles calculations unambiguously confirm the structural assignment. Detailed mechanistic analysis based on ab initio density functional theory calculations reveals a stepwise mechanism featuring a rate determining barrier of only ΔE^⧧ = 0.6 eV, consistent with the experimentally observed reaction conditions.