Water Docking Bias in [4]Helicene.

Area of Science:

• Physical Chemistry
• Spectroscopy
• Supramolecular Chemistry

Background:

• Polycyclic Aromatic Hydrocarbons (PAHs) are crucial in various chemical and physical processes.
• Chirality in PAHs, like [4]helicene, introduces unique structural and dynamic properties.
• Understanding microsolvation of chiral molecules is key to molecular recognition and self-assembly.

Purpose of the Study:

• To investigate the structure and dynamics of water clusters of [4]helicene.
• To elucidate the role of water in the solvation of chiral PAHs.
• To explore intermolecular interactions and symmetry in microsolvated chiral systems.

Main Methods:

• High-resolution rotational spectroscopy was employed to capture and analyze gas-phase water clusters.
• Microwave spectra of isotopically enriched [4]helicene species were used for structural determination.
• Analysis of spectral patterns revealed tunneling dynamics and intermolecular contacts.

Main Results:

• The structures of one- and two-water clusters of [4]helicene were unambiguously determined.
• A distinct hydrogen tunneling motion involving water hydrogens was identified in the one-water cluster.
• This tunneling motion was observed to be restricted or 'locked' in the two-water cluster.
• Intermolecular contacts, symmetry, and aromaticity effects in microsolvated chiral topologies were unveiled.

Conclusions:

• This study provides the first detailed look at water binding motifs in a chiral PAH.
• The findings highlight the influence of microsolvation on the dynamics of chiral molecules.
• The observed tunneling dynamics offer insights into the fundamental interactions governing water-PAH systems.