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E-Stilbene-Imprinted Cyclic Diphyrin and Its BIII Complex
Rampal Vishwakarma1, Daniel Blasco2, Dage Sundholm3
1School of Chemical Sciences, National Institute of Science Education and Research (NISER), An OCC of Homi Bhabha National Institute, Bhubaneswar, Odisha 752050, India.
This study introduces a novel contracted porphyrinoid, an E-stilbene-imprinted cyclic diphyrin, which exhibits non-aromaticity. Complexation with Boron(III) ions transforms this molecule from non-emissive to emissive, highlighting its potential in materials science.
Area of Science:
- Organic Chemistry
- Supramolecular Chemistry
- Materials Science
Background:
- Aromaticity in macrocycles depends on global and local π-conjugation.
- Controlling conjugation pathways is key to designing novel molecular systems.
Purpose of the Study:
- To synthesize and characterize a novel E-stilbene-imprinted cyclic diphyrin.
- To investigate the impact of structural modifications on aromaticity and conjugation.
- To explore the photophysical properties of the diphyrin upon metal complexation.
Main Methods:
- Synthesis of the E-stilbene-imprinted cyclic diphyrin.
- Structural characterization using NMR spectroscopy and X-ray crystallography.
- Photophysical studies including UV-Vis absorption and fluorescence spectroscopy.
- Complexation studies with Boron(III) ions.
Main Results:
- A new class of contracted porphyrinoid, cyclic diphyrin, was successfully synthesized.
- The ethylene twist in the E-stilbene unit disrupts global conjugation, leading to non-aromaticity.
- Complexation with Boron(III) ions induced asymmetric ring formation and transformed the non-emissive diphyrin into an emissive species in solution.
Conclusions:
- The synthesized cyclic diphyrin represents a new structural motif in porphyrinoid chemistry.
- Disruption of global conjugation can lead to non-aromaticity while preserving local aromaticity.
- Metal-induced conformational changes can tune the photophysical properties of macrocyclic systems.
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