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Multi-Macrocyclic Nanohoops Bearing Carbazole-Embedded Cycloparaphenylenes as Geometry-Adaptive Hosts Toward
Wansong Shang1, Li Jin1,2, Yang-Yang Zhang3
1Beijing National Laboratory For Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China.
Angewandte Chemie (International Ed. in English)
|July 30, 2026
Summary
Carbazole-embedded cycloparaphenylenes (CPPs) offer new routes to curved conjugated molecules. These novel macrocycles exhibit size-dependent properties and selective host-guest complexation with fullerenes.
Area of Science:
- Supramolecular Chemistry
- Organic Optoelectronics
- Materials Science
Background:
- Strained, non-planar curved conjugated molecules possess unique optoelectronic properties.
- Synthesis and modification of these molecules present significant challenges.
Purpose of the Study:
- To introduce carbazole-embedded cycloparaphenylenes (CPPs) as versatile building blocks for curved π-systems.
- To explore the synthesis, structural, optical, electronic, and supramolecular properties of novel macrocyclic compounds.
Main Methods:
- Suzuki coupling and regioselective bromination for macrocycle synthesis.
- Multi-component couplings to construct trimacrocyclic (TMC) and pentamacrocyclic (PMC) systems.
- Structural analysis (crystallography, computation), optical spectroscopy, electrochemistry, and host-guest complexation studies.
Main Results:
- Successfully synthesized functionalizable macrocyclic synthons and constructed TMC and PMC curved π-systems.
- TMC exhibits a C-shape, self-assembling into tubes, while PMC has a deformed conformation.
- Size-dependent optical properties (strong fluorescence) and electronic properties (stepwise oxidation to open-shell polycations) were observed.
- TMC forms 1:1 complexes with C60 and C70, showing adaptive host behavior and cavity expansion.
- PMC forms 2:1 (guest:host) complexes with C60 or C70.
- Host-guest recognition is primarily governed by the macrocycle's cavity geometry.
Conclusions:
- Carbazole-embedded CPPs provide a viable strategy for accessing complex curved π-systems.
- The size and shape of these macrocycles dictate their self-assembly, electronic properties, and host-guest recognition capabilities.
- Geometric complementarity of the macrocyclic cavity is the dominant factor in fullerene binding, rather than electronic effects.
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