On the Structure of Liquid Methyl Salicylate: the Role of Intramolecular Hydrogen Bonding

A study on the structure of methyl salicylate is reported using quantum mechanical calculations, molecular dynamics simulations, vibrational spectroscopy and microwave dielectric relaxation spectroscopy tools. The reported results show that a strong intramolecular hydrogen bonding is developed between the hydroxyl hydrogen and carbonyl oxygen. This intramolecular interaction is maintained in gas and liquid phases and even when diluted in inert solvents. Interaction between neighbour molecules is developed through dipolar interactions, and thus, intermolecular hydrogen bonding should be discarded for pure liquid methyl salicylate. The interaction between neighbour methyl salicylate molecules do not lead to remarkable changes in the intramolecular hydrogen bonding.