Journal of Physical Chemistry B, Vol.110, No.12, 6325-6331, 2006
Non-aqueous solvation of n-octanol and ethanol: Spectroscopic and computational studies
Raman spectroscopy was used to examine the interactions of the free O-H bonds in n-octanol and ethanol with the organic solvents carbon tetrachloride (CCl4), cyclohexane, and benzene. These spectra reveal that the solvents CCl4 and cyclohexane have a small effect on the free O-H peak of alcohols. whereas benzene as a solvent significantly red-shifts the free O-H band. Calculated spectra were generated via MP2/6-31G* calculations and the B3LYP/6-31+G**//MP2/6-31G*-derived Boltzmann populations of each ethanol complex and are consistent with the experimental results. Additional spectra were calculated using Boltzmann populations derived from sin-le-point energies at the polarizable continuum model (PCM) level with the B3LYP/6-31+G** level of theory to take overall solvent effects into account, and these simulated spectra are also largely consistent with the experimental results. Analysis of the Computational results reveals a lengthening of the O-H bond from the O-H interaction with the delocalized electronic structure of benzene as well as a bimodal distribution of the free O-H peak of the alcohol/benzene mixtures due to two distinctly different types of alcohol/benzene complexes.