Molecular recognition of catechols on the crystal-like surface of periodic mesoporous organosilica containing pyridinylethynylpyridine

A new periodic mesoporous organosilica (PMO) containing pyridinylethynylpyridine (PEPy) was successfully synthesized under basic conditions in the presence of a cationic surfactant. PEPy-PMO had a unique mesoporous structure with crystal-like walls, in which PEPy is periodically aligned. Catechols were adsorbed effectively on the PEPy moieties of the PMO surface in a mixed solvent of Et2O and hexane. The specific adsorption of catechols onto PEPy-PMO occurred with a high adsorption constant, which was evaluated using non-linear Langmuir plots. 2D HETCOR NMR and molecular dynamics calculations indicated that catechols were bound to PEPy by specific interactions, which is still a plausible mechanism. The adsorbed catechols can be easily released into the organic solvent and the recovered PEPy-PMO performed repeatedly the adsorption of catechols.