The phenyl vinyl ether-methanol complex: a model system for quantum chemistry benchmarking

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• Understanding noncovalent interactions is crucial for molecular recognition.
• Phenyl vinyl ether and methanol aggregates serve as model systems for studying these interactions.

Purpose of the Study:

• To elucidate the structural preferences and noncovalent interactions within phenyl vinyl ether-methanol aggregates.
• To investigate the influence of electronic excitation on aggregate structure.

Main Methods:

• Multi-spectroscopic approach combining vibrational and rotational spectroscopy in molecular beam experiments.
• High-level quantum-chemical calculations, including local coupled cluster methods.
• Analysis of both electronic ground (S0) and excited (S1) states.

Main Results:

• The dominant structure features a hydrogen bond between methanol's hydroxyl group and the ether oxygen (OH∙∙∙O).
• A minor isomer with π-docking involving the phenyl group was detected.
• Accurate energetic prediction required sophisticated quantum methods, highlighting the importance of London dispersion.
• Excited state analysis revealed a destabilization of the primary hydrogen-bonded structure.

Conclusions:

• The study clarifies the interplay of hydrogen bonding and dispersion forces in determining the structure of phenyl vinyl ether-methanol aggregates.
• Quantum chemical methods, particularly local coupled cluster, are essential for accurately modeling such systems.
• Electronic excitation significantly alters the stability landscape of these noncovalent complexes.