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Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
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Meso-Modified Porphyrinoids: Stimuli-Driven Conformational Plasticity, Modulation of π-Conjugation, and Bis-Rh(I)
Rampal Vishwakarma1, Mainak Das2, A Srinivasan1
1School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar 752050, Odisha, India.
Inorganic Chemistry
|December 22, 2025
Summary
Researchers designed novel macrocycles with tunable aromaticity. This breakthrough allows control over electronic properties and conformational changes in response to stimuli, impacting material science applications.
Area of Science:
- Organic Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Aromaticity in macrocycles is dictated by topology and π-electron delocalization.
- Controlling these properties is key for developing advanced functional materials.
Purpose of the Study:
- To design and synthesize novel macrocycles with tunable (anti)aromaticity and conformational plasticity.
- To investigate the relationship between molecular topology and electronic properties in π-conjugated systems.
Main Methods:
- Synthesis of meso-carbon-amended porphyrinoids with ortho-benzannulation and vinylogous linkages.
- Characterization of conformational changes and aromaticity using spectroscopic and computational methods.
- Investigation of metal complexation effects on electronic and structural properties.
Main Results:
- The designed macrocycles exhibit stimuli-responsive conformational changes.
- Tunable aromaticity was observed, ranging from Hückel antiaromaticity in freebases to weak Möbius aromaticity upon protonation.
- Bis-Rh(I) complexation led to nonaromatic, foldameric structures with η² coordination and panchromatic absorption.
Conclusions:
- The study demonstrates a successful design strategy for creating macrocycles with controllable topology-dependent properties.
- This work provides insights into structure-property relationships in π-conjugated macrocycles.
- The developed systems hold potential for applications in stimuli-responsive materials and molecular electronics.
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