Chirality-dependent interactions between molecular propeller structures in solution. Chiral recognition and...

Area of Science:

• Photochemistry
• Supramolecular Chemistry
• Spectroscopy

Background:

• Chirality plays a crucial role in molecular recognition and biological processes.
• Understanding chiral interactions is vital for developing enantioselective reactions and materials.
• Dynamic excited-state quenching offers a sensitive probe for studying transient molecular interactions.

Purpose of the Study:

• To investigate chirality-dependent intermolecular interactions in dynamic excited-state quenching processes.
• To use time-resolved chiroptical luminescence (TR-CL) to monitor differential decay kinetics of chiral enantiomers.
• To elucidate the role of molecular structure in chiral recognition and discrimination.

Main Methods:

• Time-resolved chiroptical luminescence (TR-CL) measurements.
• Excitation of racemic luminophores with polarized laser radiation.
• Monitoring differential decay kinetics of LambdaL* and DeltaL* enantiomers in the presence of chiral quenchers (CQ).

Main Results:

• Observed differences in decay kinetics indicate differential quenching efficiencies for LambdaL*-CQ vs. DeltaL*-CQ interactions.
• Chiral discriminatory interactions were confirmed in twelve luminophore-quencher systems across various temperatures and solvents.
• Quenching occurs via electronic energy transfer in transient encounter complexes, with parameters reflecting complex stability, lifetime, and dynamics.

Conclusions:

• Small structural differences in propeller-shaped molecules lead to significant variations in chiral recognition and discrimination.
• TR-CL is a powerful technique for probing chirality-dependent intermolecular interactions.
• The study provides insights into the fundamental principles governing chiral molecular recognition.