Evidence for the mode of adsorption of anisoles on silica from an infrared study of hydrogen bonds between triphenylsilanol and anisoles in solution

Abstract

Association constants and infrared spectroscopic shifts Δν_OH are reported for the formation of hydrogen bonds between triphenylsilanol and anisole, six substituted anisoles (2,6-Me₂, 4-Me, 4-Cl, 4-Br, 2-F, 4-NO₂), nitrobenzene and 4-nitrotoluene. The data are compared with infrared spectroscopic results for the adsorption of the hydrogen-bond acceptor molecules on to the surface of silica immersed in n-heptane. Parallel behaviour for the formation of hydrogen-bonded complexes in solution and at the solid/liquid interface provides information about the types of interaction which exist between surface silanol groups and adsorbed substituted anisole molecules.