One-Dimensional Polycyclic Aromatic Hydrocarbons Incorporating Multiple Dithiafulvene Units-Novel Multi-Redox and...

Area of Science:

• Organic Chemistry
• Materials Science
• Electrochemistry

Background:

• Polycyclic aromatic hydrocarbons (PAHs) are π-conjugated systems with diverse electronic properties.
• Dithiafulvene (DTF) units can be incorporated into organic scaffolds to tune redox behavior.
• Multi-redox active materials are crucial for applications in electronics and energy storage.

Purpose of the Study:

• To synthesize and characterize novel polycyclic aromatic hydrocarbon (PAH) scaffolds functionalized with dithiafulvene (DTF) units.
• To investigate the impact of varying numbers of DTF units on the redox properties of these PAH scaffolds.
• To explore the potential of these materials in electrochromic and conducting applications.

Main Methods:

• Synthesis of PAH cores with carbonyl groups followed by Horner-Wadsworth-Emmons reactions to introduce DTF units.
• Cyclic voltammetry to study the multi-redox behavior of tri-DTF and tetra-DTF PAH scaffolds.
• Electrocrystallization to generate and characterize radical cation salts.

Main Results:

• Novel tri-DTF and tetra-DTF PAH scaffolds were successfully synthesized.
• These planar molecules exhibit strong associations in neutral and oxidized states with distinct UV-vis-NIR absorptions.
• The number of DTF units critically influenced redox properties: tri-DTF PAHs showed stepwise oxidation, while tetra-DTF PAHs underwent a single three-electron oxidation.
• Mixed-valence and radical cation salts were generated via electrocrystallization.

Conclusions:

• The synthesized multi-DTF PAHs possess tunable multi-redox characteristics based on the number of DTF units.
• These materials demonstrate potential as components for electrochromic and conducting materials.
• Their redox-controllable nature makes them suitable for applications in molecular self-assembly and disassembly.