Microhydration Dynamics in Molecular Photoswitches: Equilibrium State Reconfiguration in Imine-Based Architectures

Area of Science:

• Physical Chemistry
• Molecular Spectroscopy
• Computational Chemistry

Background:

• Molecular photoswitches require structural changes in solution for functional performance.
• Gas-phase microsolvation studies offer insights into hydrated environments.
• Camphorquinone imine is a chiral molecule with potential motor-like functions.

Purpose of the Study:

• Investigate structural properties and microhydration dynamics of camphorquinone imine.
• Analyze the impact of water complexation on the molecule's conformational states.
• Understand the role of early solvation in molecular switch behavior.

Main Methods:

• Gas-phase molecular rotational resonance spectroscopy using supersonic jets.
• Quantum-chemistry calculations.
• Detection and analysis of first- and second-order water complexes.

Main Results:

• Initial hydration reverses the relative stability of the open (E) and closed (Z) forms of camphorquinone imine.
• Water molecules show notable mobility even at low temperatures (1 K).
• A higher-energy closed (Z) water complex provides insights into switching energy barriers.

Conclusions:

• Early solvation dramatically influences the conformational equilibrium of molecular photoswitches.
• Water molecule mobility is significant in the absence of strong secondary interactions.
• Understanding microhydration is crucial for designing light-activated molecular systems.