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Dual-State Mechano- and Electrochromic Responses Enabled by Sterically Strained Diazaanthraquinodimethanes
Karin Noro1, Ayano Tani2, Tomoki Tadokoro1
1Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan.
The Journal of Organic Chemistry
|September 2, 2025
Summary
New diazaanthraquinodimethane (N2AQD) materials exhibit reversible optical changes in response to mechanical and electrical stimuli. Ortho-substituted derivatives show enhanced switching ability and tunable near-infrared absorption for advanced functional systems.
Area of Science:
- Materials Science
- Organic Chemistry
- Photochemistry
Background:
- Stimulus-responsive materials with reversible optical properties are crucial for advanced functional systems.
- Diazaanthraquinodimethane (N2AQD) derivatives offer potential for tunable optical characteristics.
Purpose of the Study:
- To design and synthesize N2AQD derivatives with ortho-substituted 4-methoxyphenyl groups.
- To investigate the impact of ortho-substitution on molecular conformation, redox stability, and optical properties.
- To explore mechanochromic and electrochromic behavior for multifunctional chromic applications.
Main Methods:
- Synthesis of novel N2AQD derivatives featuring ortho-substituted 4-methoxyphenyl groups.
- Spectroscopic analysis (UV-Vis absorption, emission) to characterize optical properties.
- Electrochemical studies to evaluate redox behavior and electrochromism.
- Solid-state characterization to observe mechanochromic transitions.
Main Results:
- Ortho-substitution induces structural deformation, enhancing conjugation and switching ability.
- The ortho-dimethyl substituted N2AQD derivative exhibits red-shifted absorption in neutral and dicationic states.
- Mechanochromism (ground- and excited-state changes) observed in solid-state due to phase transitions.
- Reversible electrochromism demonstrated in solution.
Conclusions:
- N2AQD derivatives with ortho-substitution are promising platforms for multifunctional chromic materials.
- These materials exhibit tunable optical properties and respond reversibly to mechanical and electrical stimuli.
- The findings pave the way for developing advanced responsive materials for various applications.
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