Information on the bonding of organic ligands to hydrous metal oxide surfaces, necessary to gain insight into the mechanisms of surface reactivity, was extracted using attenuated total reflection-Fourier transform infrared spectroscopy. Various ligands were investigated in-situ on the surface of δ-Al2O3 in water. Keeping the study of structure with respect to surface reactivity in the foreground, we report here specifically on the model ligand salicylate, which we also examined on the surfaces of other oxides, including corundum, hematite, lepidocrocite, and goethite. Because the direct ligand-metal bond vibrations absorb in the same region as the metal-oxygen vibrations in the bulk oxide, evidence of bonding was obtained by observing changes in the spectrum of the ligand itself. Results show that salicylate does not bond identically on all metal oxide surfaces. In the cases examined, the chemical composition of the metal oxide, as opposed to the morphology, determined the structure of the ligand surface complex.
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Biber et al. (1994) studied this question.