Phenylenediamine-Linked, Folded Nanographene Dimers: Access to Structure-Dependent Redox Capability

Area of Science:

• Organic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Polycyclic aromatic hydrocarbons (PAHs) with open-shell or redox characteristics are crucial for advanced electronic materials.
• Developing novel nanographenes (NGs) with tailored properties remains a key challenge in materials science.

Purpose of the Study:

• To synthesize and characterize novel phenylenediamine-linked nanographenes (NGs).
• To investigate the 3D conformations, electronic structures, and redox properties of these NGs.
• To explore their potential for applications requiring specific electronic and redox behaviors.

Main Methods:

• Synthesis of phenylenediamine-linked nanographenes (1-3) by connecting aza-hexa-peri-hexabenzocoronene (HBC) units to different phenylene linkers.
• X-ray crystallographic analysis to determine 3D structures.
• Quantum chemical calculations to elucidate electronic structures.
• Electrochemical studies to assess redox properties.

Main Results:

• Compounds 1-3 adopted anti-folded, Z-shaped 3D structures with rotatable single bonds.
• Compound 1, upon one-electron oxidation, formed a stable monoradical cation with an unprecedented syn-folded structure.
• Compounds 2 and 3 exhibited tunable redox activity from neutral to dication states, controllable via chemical oxidation/reduction.

Conclusions:

• The study successfully synthesized and characterized novel phenylenediamine-linked nanographenes with distinct 3D architectures.
• The findings highlight structure-dependent redox properties, with potential for precise control over electronic states.
• These NGs offer promising platforms for developing advanced functional materials with tailored electronic and redox characteristics.