Monomolecular Layers of Pyrene as a Sensor to Dicarboxylic Acids

Abstract

A novel photoinduced luminescence film has been prepared by immobilizing pyrene on a quartz plate surface via a flexible long spacer. The film shows combined monomer and excimer emission of pyrene both in wet and dry states, and the excimer may be formed mainly by direct excitation of ground-state dimers and/or monomers in aggregates. Classical Birks' scheme plays a little role in the formation of the excimers. The emission of the film is sensitive to the presence of dicarboxylic acids, including ethanedioic acid, malonic acid, succinic acid, etc. The emission in the monomer and excimer region increases with addition of the acids. The time needed for the emission to reach equilibrium depends on the nature of the acids. It has been shown that the longer the chains of the acids, the more time is needed. This observation is explained by considering the conformational reorganization of the immobilized pyrene due to insertion of the dicarboxylic acids into the space between neighboring spacers. Experimental results from similar studies using formic acid and acetic acid are in support of this explanation. Furthermore, the response of the film to dicarboxylic acids is reversible.

Engineering Silicon Oxide Surfaces Using Self‐Assembled Monolayers

“…The reason for the limited use of fluorescence spectroscopy on gold lies in the strong quenching effect of the gold substrate on the fluorescence of nearby molecules, [156] thus making oxide surfaces such as SiO 2 the surface of choice for the immobilization of fluorescent sensing molecules. [157][158][159][160][161] One of the first immobilized sensors was reported by de Silva et al [162] The sensor consisted of an anthracene fluorophore covalently connected to an APS layer. The fluorophore could behave as a pH probe depending on the protonation state of the amino group.…”

Gestaltung der Siliciumoxidoberfläche durch selbstorganisierte Monoschichten

“…[156] Aus diesem Grund werden zur Immobilisierung fluoreszierender Sensormoleküle Oxidoberflächen wie SiO 2 gewählt. [157][158][159][160][161] Eines der ersten immobilisierten Sensorsysteme wurde von De Silva et al entwickelt. [162] Es bestand aus kovalent an APS-SAMs gebundenen Anthracenfluorophoren, die, abhän-gig vom Protonierungsgrad der Aminogruppen, als pHSonden eingesetzt werden konnten.…”

Silicon Based Nanocoatings on Metal Alloys and Their Role in Surface Engineering

“…Fluorescent spectroscopy has limited use on gold because of the quenching effect of the gold substrate on the nearby fluorescent molecules [289]. Surfaces like SiO 2 , which can support alkylsilane SAMs very well, have become the substrate of choice for immobilization of fluorescent sensing molecules [290][291][292]. One of the early fluorescent sensors was developed by de Silva et al, which was composed of an anthracene fluorophore covalently attached to aminopropyltrimethoxy silane (APTS) monolayer [293].…”