The Interplay of Inter- and Intramolecular Hydrogen Bonding in Ether Alcohols Related to n-Octanol

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Materials Science

Background:

• Ether alcohols are versatile compounds with applications in solvents and pharmaceuticals.
• Understanding their hydrogen bonding is crucial for predicting physical properties.
• Molecular dynamics (MD) simulations offer a powerful tool to probe molecular interactions.

Purpose of the Study:

• To investigate the effect of ether functionality position on hydrogen bonding in n-octanol derivatives.
• To elucidate the relationship between hydrogen bonding and macroscopic physical properties.
• To compare the performance of OPLS-AA and CHARMM force fields in simulating these systems.

Main Methods:

• All-atom molecular dynamics (MD) simulations were performed.
• Two classical force fields, OPLS-AA and CHARMM, were employed.
• Analysis included radial distribution functions (RDFs) and hydrogen bond characterization.

Main Results:

• Intramolecular hydrogen bonding is prominent in shorter-chain ether alcohols (n=3, 4) and diminishes with increasing chain length.
• Intermolecular hydrogen bonding is stronger between hydroxyl groups (OH-OH) than between hydroxyl and ether groups (OH-OE).
• Higher temperatures reduce intermolecular hydrogen bonding but slightly increase intramolecular bonding and reduce end-to-end distances.

Conclusions:

• The position of the ether functionality dictates the extent and type of hydrogen bonding.
• Hydrogen bonding significantly influences density, self-diffusion, and viscosity.
• OPLS-AA and CHARMM force fields provide comparable qualitative insights, differing mainly in quantitative hydrogen bonding predictions.