Gas-Phase Benzene-Methanol Dimer Configurations: Geometries, Relative Stabilities, and Interaction Energies.

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Molecular Interactions

Background:

• The O-H···π nonbonded interaction is prevalent in diverse systems, including small molecules and biological contexts like protein-ligand binding.
• Understanding these interactions is key to comprehending molecular recognition and assembly.

Purpose of the Study:

• To investigate the energetics and stability of different configurations within the benzene-methanol dimer.
• To analyze the influence of temperature on the interaction energies of these configurations.

Main Methods:

• Quantum mechanical calculations were employed to study four gas-phase configurations of the benzene-methanol dimer.
• Geometry optimization and frequency calculations were performed using MP2/aug-cc-pVQZ.
• Electronic energies were computed up to the CCSD(T)/complete basis set (CBS) limit.

Main Results:

• The O-H···π configuration was identified as the most stable, with a CCSD(T)/CBS interaction energy of -4.09 kcal mol⁻¹.
• Other configurations (CH₃···π and Bz-H···O) exhibited lower interaction energies, ranging from -2.00 to -2.60 kcal mol⁻¹.
• Temperature-dependent Gibbs relative and interaction free energies were calculated from 10-800 K.

Conclusions:

• The O-H···π interaction is the dominant binding motif in the benzene-methanol dimer.
• Computational methods provide accurate insights into nonbonded interactions relevant to chemical and biological systems.
• Temperature plays a role in the relative stability of different molecular configurations.