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

Area of Science:

• Materials Science
• Organic Chemistry
• Surface Science

Background:

• Designing functional electronic materials requires precise control over dopant integration in graphene-derived polycyclic aromatic hydrocarbons.
• Substitutional doping at specific lattice positions is key for tailoring material properties.

Purpose of the Study:

• To report a mild method for synthesizing tetraazateranthene through thermally induced oxidative cyclodehydrogenation.
• To investigate the formation of four covalent C-N bonds in tetraazateranthene on metal surfaces.

Main Methods:

• Thermally induced oxidative cyclodehydrogenation of dianthryl pyrazino[2,3-g]quinoxalines.
• Surface-based synthesis on Au(111) and Ag(111) substrates.
• Characterization using bond-resolved scanning probe microscopy and differential conductance spectroscopy.
• Mechanistic analysis via ab initio density functional theory calculations.

Main Results:

• Successfully formed tetraazateranthene via a mild oxidative cyclodehydrogenation process.
• Unambiguously confirmed the structure using scanning probe microscopy and spectroscopy.
• Density functional theory calculations revealed a stepwise mechanism with a low activation barrier (0.6 eV).

Conclusions:

• The study demonstrates an efficient and mild route to tetraazateranthene, a key functional electronic material.
• The findings provide fundamental insights into the surface-assisted synthesis of complex polycyclic aromatic hydrocarbons.
• This work facilitates the design of novel graphene-derived materials with tailored electronic properties.