Elucidation of hydrogen bonding formation by a computational, FT-IR spectroscopic and theoretical study between benzyl alcohol and isomeric cresols

Abstract

The densities (ρ) of binary mixtures of benzylalcohol with o-cresol, m-cresol and p-cresol have been measured at ambient atmospheric pressure over the entire composition range, and at a temperature range from 303.15 K to 323.15 K, with the help of a Rudolph Research Analytical digital densitometer (DDH-2911 model). Moreover, the speeds of sound (u) for these mixtures were also carried out at 303.15 K and 313.15 K. The measured data were used to calculate the excess volumes (V^E) and excess isentropic compressibilities (κ^E_s), and the results were computed in terms of Redlich–Kister & Hwang equations. The experimental speed of sound was compared in terms of Schaff's collision factor theory (CFT) and Jacobson's free length theory (FLT). The experimental excess molar volume (V^E) was also used to test the validity of the Prigogine–Flory–Patterson (PFP) theory at 303.15 K and 313.15 K. The existence of hydrogen bonding in the binary mixtures of benzyl alcohol with cresols is further conformed by high level theoretical calculation, namely, density functional theory (DFT-B3LYP) with 6-311++G(d,p) basis sets was used to study the geometries, bond characteristics, interaction energies and natural bonding orbital (NBO) analysis of the hydrogen-bonded complexes in the gas phase, and the cross-associations in the mixture studied were investigated via quantum chemical calculations. The measured data were used to study intermolecular interactions between component molecules of binary mixtures with FT-IR spectroscopic studies.