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Enabling Stereochemical Communication and Stimuli-Responsive Chiroptical Properties in Biphenyl-Capped Cyclodextrins
Giovanni Preda1,2, Sebastian Jung2, Gennaro Pescitelli3
1Department of Chemistry and INSTM Research Unit, University of Pavia, Via Taramelli 12, 27100, Pavia, Italy.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|September 5, 2023
Summary
Researchers developed novel chiroptical materials by linking cyclodextrins (CDs) with biphenyl units. These materials effectively transfer chirality, enabling tunable chiroptical properties responsive to external stimuli like temperature and solvent.
Area of Science:
- Supramolecular Chemistry
- Materials Science
- Chiroptical Materials
Background:
- Chiroptical materials are crucial for optoelectronics and data encryption.
- Native chiral pool molecules like cyclodextrins (CDs) often lack suitable chromophores for advanced chiroptical applications.
- Developing new methods to impart significant chiroptical properties to existing chiral building blocks is essential.
Purpose of the Study:
- To synthesize and characterize a novel two-level molecular stack for stimuli-responsive chiroptical materials.
- To effectively translate stereochemical information from cyclodextrins (CDs) to an axially chiral biphenyl unit.
- To investigate the mechanism of chirality transfer and the influence of external stimuli on chiroptical properties.
Main Methods:
- Synthesis of α- and β-permethylated cyclodextrins capped with difunctionalized biphenyl units.
- Characterization using crystallographic analysis, computational modeling, and electronic circular dichroism (ECD) spectroscopy.
- Investigation of stimuli-responsive behavior (temperature, solvent) on chiroptical properties.
Main Results:
- Successful synthesis of a molecular stack comprising cyclodextrins and biphenyl units.
- Demonstration of effective chirality transfer from the CD core to the biphenyl cap via intramolecular hydrogen bonds.
- Observation of stimuli-responsive tuning of chiroptical properties by external factors.
- Elucidation of the chirality transfer mechanism through combined experimental and computational approaches.
Conclusions:
- The developed molecular architecture enables efficient transfer of nonchromophoric stereochemical information from CDs to biphenyl caps.
- The synthesized materials exhibit tunable chiroptical properties, opening avenues for advanced optoelectronic and data encryption applications.
- Synergistic action of intramolecular hydrogen bonds in the biphenyl cap acts as a stereoselective actuator for chirality transfer.
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