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Updated: Aug 23, 2026

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Amorphous silica as a versatile supermolecular ligand for Ni(II) amine complexes: toward interfacial molecular
Souhir Boujday1, Jean-François Lambert, Michel Che
1Laboratoire de Réactivité de Surface, UMR 7609, CNRS, Université Pierre et Marie Curie, Paris, France.
Abstract:
Selective adsorption of Ni(II) amine complexes used as precursors for supported catalysts was studied on amorphous silica surfaces. The nature of the adsorption sites was probed by [Ni(en)(dien) (H2O)]2+, [Ni(en)2(H2O)2]2+, and [Ni(dien)(H2O)3]2+ (en = ethylenediamine, dien = diethylenetriamine), which respectively contain one, two, and three labile aqua ligands. The silica surface acts as a mono- or polydentate ligand that can substitute the aqua ligands of the Ni(II) complexes in an inner-sphere adsorption mechanism. Room-temperature adsorption isotherms indicate that each nickel complex selects a limited number of adsorption sites; different sites are recognised by the three complexes, even though they have the same charge and comparable sizes. Several spectroscopic techniques (UV/Vis/NIR, EXAFS, and 29Si NMR) were used to confirm the selective character of the interaction of Ni(II) amine complexes with the silica surface. The specific sites include both silanol/silanolate groups in the same number as the original labile ligands and other surface groups that probably act as hydrogen-bond acceptors. These two types of groups cooperate to result in interfacial molecular-recognition phenomena with interactional complementarity.
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