The first microsolvation step for furans: New experiments and benchmarking strategies

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• Understanding molecular interactions is crucial for chemical processes.
• Microsolvation studies provide insights into solvent effects at the molecular level.
• Accurate theoretical descriptions of molecular complexes are essential for predicting chemical behavior.

Purpose of the Study:

• To benchmark quantum-chemical methods for describing furan-methanol complexes.
• To investigate the site-specific first microsolvation step of furan derivatives.
• To compare experimental and theoretical approaches for analyzing molecular complexes.

Main Methods:

• Infrared and microwave spectroscopy in supersonic jet expansions.
• Quantum-chemical calculations including harmonic and anharmonic approximations.
• Deuteration experiments to probe zero-point energy contributions.

Main Results:

• Microwave spectroscopy confirmed top coordination of methanol to the furan ring, ruling out in-plane docking.
• Few composite computational methods achieved satisfactory performance within the harmonic approximation.
• Discrepancies between experimental and theoretical isomer abundance were tentatively attributed to electronic structure deficiencies.

Conclusions:

• The harmonic approximation is largely justified for zero-point energy in these systems.
• Current anharmonic treatments are insufficient for uniform and systematically improved performance.
• Further refinement of electronic structure and nuclear dynamics is needed for precise theoretical predictions.