Doping a Nanographene with a Formal Ni^IV Center

Area of Science:

• Materials Chemistry
• Organic Chemistry
• Nanotechnology

Background:

• Hexa-peri-hexabenzocoronene (HBC) derivatives are key nanographene building blocks.
• Metal-doped nanographenes offer unique electronic and catalytic properties.
• Carbaporphyrin units can be incorporated into larger aromatic systems.

Purpose of the Study:

• To synthesize a novel nanographene ligand incorporating a carbaporphyrin unit.
• To create and characterize organometallic complexes, including a high-valent nickel species.
• To explore the potential for postsynthetic heteroatom doping in nanographenes.

Main Methods:

• Synthesis of nanographene ligand 2 and its Ni(II) complex 3.
• Oxidation of complex 3 to Ni(IV) species 4 using CuCl2.
• Characterization using X-ray photoelectron spectroscopy (XPS), NMR, UV-vis-NIR, cyclic voltammetry, and DFT calculations.
• Reaction of complex 4 with water and subsequent demetalation.

Main Results:

• Successful synthesis of nanographene ligand 2 and its Ni(II) complex 3.
• Formation and characterization of the first reported Ni(IV) nanographene complex 4.
• Complex 4 reacts with water to form an oxygen-inserted complex 5, leading to doped nanographene 6.
• DFT calculations and XPS confirmed the Ni(IV) oxidation state.

Conclusions:

• This work introduces a new Ni(IV) nanographene complex, advancing metal doping chemistry.
• The developed methods provide access to postsynthetic heteroatom doping of nanographene frameworks.
• The findings open avenues for novel functional materials based on doped nanographenes.