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Siamese Twin Homocarbaporphyrin Dimer: Nonplanar Architecture, Localized Conjugation and Bis-BIII Complex
Rampal Vishwakarma1, Prakhar Gupta2, Ashutosh Behera1
1School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar, Odisha, 752050, India.
We designed a rigid, figure-eight shaped homocarbaporphyrin dimer. This nonaromatic macrocycle maintains its shape under external stimuli, advancing novel π-architectures.
Area of Science:
- Supramolecular Chemistry
- Organic Chemistry
- Materials Science
Background:
- Complex π-systems with nonplanar geometries are crucial for unique electronic properties.
- Macrocyclic scaffolds that maintain stable, nonplanar conformations are key to exploring new conjugation and stimuli-responsive behaviors.
Purpose of the Study:
- To synthesize and characterize a structurally rigid, double-looped homocarbaporphyrin dimer.
- To investigate the conformational stability and electronic properties of the nonplanar macrocycle.
Main Methods:
- Synthesis of a double-looped homocarbaporphyrin dimer via fusion of ortho-benzannulated monomeric units.
- Spectroscopic studies (e.g., NMR, UV-Vis) and theoretical calculations.
- Single-crystal X-ray diffraction analysis.
Main Results:
- A figure-eight conformation was achieved, precluding macrocyclic π-delocalization and resulting in a nonaromatic system.
- The homocarbaporphyrin dimer exhibited exceptional shape persistence upon protonation and Boron(III) coordination.
- Structural and electronic properties were confirmed through spectroscopic, theoretical, and crystallographic analyses.
Conclusions:
- This study presents a novel, shape-persistent, nonaromatic macrocyclic system with a unique figure-eight architecture.
- The findings provide a blueprint for designing advanced π-architectures with tunable electronic properties for various applications.
- The demonstrated shape persistence offers potential for stimuli-responsive materials.
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