Cold-Captured Dynamic Hydration Networks in Oxime-Based Photoswitches: A Theoretical Challenge Uncovered by...

Area of Science:

• Molecular nanotechnology
• Physical chemistry
• Supramolecular chemistry

Background:

• Photoswitches are crucial for manipulating biochemical processes at the molecular level.
• Understanding photoswitch conformational dynamics, especially solvation effects, is vital for optimizing synthetic strategies.
• Camphorquinone-oxime serves as a prototype photoswitch due to its oxime moiety and chiral camphor group.

Purpose of the Study:

• To investigate the structure and micro-hydration dynamics of camphorquinone-oxime.
• To resolve discrepancies in theoretical predictions regarding the energy ordering of its switch states.
• To elucidate the cooperative integration of the oxime moiety within water clusters.

Main Methods:

• Jet-cooled rotational spectroscopy to probe molecular structure and dynamics.
• Quantum chemistry calculations to model interactions and energy landscapes.
• Isotopic substitution to validate theoretical findings and understand hydration dynamics.

Main Results:

• The oxime moiety cooperatively binds to water chains (dimer, trimer) and 3D structures (tetramer).
• Disagreements among theoretical methods regarding energy states of the photoswitch were addressed.
• Evidence for concerted hydration dynamics was observed through combined experimental and theoretical analysis.

Conclusions:

• The study provides atomic-level insight into the micro-hydration of a prototype photoswitch.
• The flexible first solvation layer's influence on switching dynamics is highlighted.
• Findings guide the development of more efficient photoswitch systems for molecular nanotechnology.