Probing intermolecular communication with surface-attached pyrene

We report on the covalent attachment of pyrene derivatives to solid substrates and their spectroscopic and electrochemical characterization. We have constructed several molecular assemblies attached to silica and indium-doped tin oxide surfaces where pyrene molecules are co-immobilized with other functionalities. It was shown that the addition of hydrophobic molecules to the pyrene-containing interface results in a significant decrease in the pyrene I1/I3 vibronic emission band ratio and an increase in the water drop contact angle due to increased hydrophobicity of the interface. The co-attachment of perylenedodecanoic acid, for which the absorption band overlaps with the emission spectrum of pyrene, shows significant intermolecular communication between these species. The co-immobilization of ferrocene serves as an effective fluorescence quencher for tethered pyrene. In all cases, our data point to significant intermolecular communication between adsorbate species, and the combination of spectroscopic and electrochemical interrogation provides insight into the loading density and local environment(s) characteristic of these interfaces.