Influence of solute-solvent coordination on the orientational relaxation of ion assemblies in polar solvents J. Chem. Phys. 136, 014501 (2012) Theoretical study of the aqueous solvation of HgCl2: Monte Carlo simulations using second-order Moller-Plessetderived flexible polarizable interaction potentials J. Chem. Phys. 136, 014502 (2012) A two-dimensional-reference interaction site model theory for solvation structure near solid-liquid interface J. Chem. Phys. 135, 244702 (2011) On the solvation structure of dimethylsulfoxide/water around the phosphatidylcholine head group in solution JCP: BioChem. Phys. 5, 12B611 (2011) Additional information on J. Chem. Phys. Diffusivities of pseudoplanar molecules at trace concentration in methanol have been measured at 298.2 K using Taylor's dispersion method. The data of the polar and nonpolar aromatic solutes are compared, and the effects due to solute-solvent interactions on diffusion, together with the solvation numbers, are determined. In this study, the effects are combined with the recently developed solute hydrogen-bond scales to unravel hydrogen bonding between solute and solvent. It is found that the degrees of association of the solutes with methanol decrease in the sequence hydroquinoneϾaromatic acidsϾphenolsϾaromatic aminesϾaprotic aromatic compounds. Except for o-nitrophenol, which is capable of intramolecular hydrogen bonding, all aromatic acids, phenols, and amines studied behave more as hydrogen-bond donor than acceptor in methanol. The present work also indicates that motions of associated molecules can be understood in terms of the molecular behavior of nonassociated solutes and the hydrogen-bond acidity/basicity of polar solutes.