Sensors photochemical

Self-assembly of Au(I) complexes through weak Au(I) - - -Au(I) interactions is now recognized as an interesting feature of heavy transition metal chemistry whose wider implications are slowly being understood. The utility of these compounds as chemical and photochemical switches or as energy storage devices and photochemical sensors is one of the possible fruits of this research. Although a com-... 

Ion Channels and Their Models, p. 742 Ion-Selective Electrodes, p. 747 lonophores, p. 760 Photochemical Sensors, p. 1053... 

Biosensors, p. 115 DNA Nanotechnology, p. 475 Fluorescence Sensing of Anions, p. 566 Fluorescent Sensors, p. 572 Imaging and Targeting, p. 687 Luminescent Materials, p. 875 Photochemical Sensors, p. 1053 Supramolecular Photnchernistn, p. 1434... 

A different approach to dendritic sensors involves modification of a sensor core unit with dendritic substituents to confer beneficial solubility properties. An example of a sensor core unit is the porphyrin macrocycle, a heterocycle that has been employed extensively in prototypical photochemical sensor systems. Vinogradov and co-workers have exploited the versatile photoactive porphyrin sensor unit as a fluorescence-based pH indicator for use in biological assays [73], by attaching acid terminated polyamide-ether dendrons as substituents (Figure 8.12). The two imino nitrogen atoms present in the free-base porphyrin are susceptible to stepwise protonation to afford initially a cation and then a dication, respectively. Upon protonation, both the emission and absorption fluorescence spectroscopic characteristics of the porphyrin core are subject to dramatic hypochromic shifts. This spectroscopic phenomenon formed the basis for an accurate pH indicator with potential applications in proton gradient determination studies in biological systems. 

L. Campanella, G. De Angelis, and G. Visco. Chemometric investigation of the efficiency of different Ti02-based catalysts as principal components of TOC photochemical sensors under development. Anal. Bioanal. Chem., 376 467-475, 2003. 

G. Visco, F. Bellanti, L. Campanella, T. Mazzella, and V. Nobili. Optimization of a photochemical sensor for total organic carbon measurement. Ann. Chim., 95(3—4) 185-198, 2005. 

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