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Fluorescent photoionic devices with two receptors and two switching mechanisms: applications to pH sensors and implications for metal ion detection

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Callan, JF, de Silva, AP, Ferguson, J, Huxley, AJM and O'Brien, AM (2004) Fluorescent photoionic devices with two receptors and two switching mechanisms: applications to pH sensors and implications for metal ion detection. TETRAHEDRON, 60 (49). pp. 11125-11131. [Journal article]

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DOI: 10.1016/j.tet.2004.08.057

Abstract

Two leading designs of fluorescent sensors are combined to yield the novel hybrid system of the `Fluorophore-Receptor(1)-Spacer-Receptor(2)' format. We use 4-(dialkylaminoalkylamino)-7-nitrobenzo-2-oxa- 1,3-diazoles as examples. The emission from internal charge transfer excited states in the present instances are highly responsive to N-H deprotonation as well as being quenched by intramolecular tertiary amine groups via photoinduced electron transfer (PET). When applied to pH sensing, this leads in favourable cases to two steps in the fluorescence-pH profile which can be viewed as a multi-stable photoionic device, even though single steps are more usual. The former situation is favoured when the two proton-associated equilibria are sufficiently separated on the pH scale and when the PET process is of moderate efficiency. These systems have the added feature of excitation/emission wavelengths in the visible region. As a secondary theme, we point out that caution is required when designing sensors for transition metal ions from systems with intrinsically proton-sensitive fluorescence due to receptors either integrated with or spaced from the fluorophore. (C) 2004 Elsevier Ltd. All rights reserved.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Pharmacy and Pharmaceutical Science
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Pharmaceutical Science and Practice
ID Code:4053
Deposited By:Professor John Callan
Deposited On:05 Jan 2010 14:13
Last Modified:19 Nov 2012 15:28

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