Photoinduced electron transfer sensors

M -Dialkyldiazacrown ethers and their precursors fcis(alkylamino) derivatives of tri- and tetraethylene glycols were prepared <96CCCC622>. New hydroxy-bearing dibenzo-azocrown ethers have been conveniently prepared utilizing l,3-Ws(2-formylphenoxy)-2-propanol and a diamine, followed by reduction of the intermediate diimine <96P1197>. Fluorescent photoinduced electron transfer sensor 5 with monoaza-18-crown-6 and guanidinium receptor units demonstrated a fluorescence with T -aminobutyric acid in a mixed... 

James TD, Sandanayake KRAS, Iguchi R et al (1995) Novel saccharide-photoinduced electron-transfer sensors based on the interaction of boronic acid and amine. J Am Chem... 

Appropriate combinations of boronic acid and fluorophores lead to a remarkable class of fluorescent sensors of saccharides (Shinkai et ah, 1997, 2000, 2001). The concept of PET (photoinduced electron transfer) sensors (see Section 10.2.2.5 and Figure 10.7) has been introduced successfully as follows a boronic acid moiety is combined intramolecularly with an aminomethylfluorophore consequently, PET from the amine to the fluorophore causes fluorescence quenching of the latter. In the presence of a bound saccharide, the interaction between boronic acid and amine is intensified, which inhibits the PET process (Figure 10.42). S-l is an outstanding example of a selective sensor for glucose based on this concept (see Box 10.4). 

A. Prasanna de Silva, and H. Q. Nimal Gunaratne, Fluorescent PET (Photoinduced Electron Transfer) sensors selectives for submicromolar calcium with quantitatively predictable spectral and ion-binding properties, J. Chem, Soc., Chem, Common. 186 (1990). 

Bissell RA, de Silva AP, Gunaratne HQN, Lynch PLM, Maguire GEM, McCo, CP, Sandanayake KRAS (1993) Fluorescent PET (Photoinduced Electron Transfer) Sensors. 168 223-264... 

Billing R, Rehorek D.Hennig H (1990) Photoinduced Electron Transfer in Ion Pairs. 158 151 -199 Bissell RA, de Silva AP, Gunaratne HQN, Lynch PLM, Maguire GEM, McCo, CP, Sandanayake KRAS (1993) Fluorescent PET (Photoinduced Electron Transfer) Sensors. 168 223-264 Blasse (1994) Vibrational Structure in the Luminescence Spectra of Ions in Solids. 171 1-26... 

Fluorescent PET (photoinduced electron transfer) sensors are considered to be those molecular systems where the binding of ions and other species leads to the perturbation of the competition between the de-excitation pathways of fluorescence and electron transfer. The early developments in this field are traced and the design logic of these sensors is detailed. A variety of examples drawn from different areas of chemistry are classified according to the fluorophore-spacer-receptor format and their photophysical behaviour is rationalized in terms of fluorescent PET sensor principles. Cases are pointed out where such experimental data are unavailable but desirable. During these discussions, the relevance of twisted fluorophore-receptor systems and the contrast with integrated fluorophore-receptor systems is noted. The utility of the fluorescence on-ofP phenomenon in these PET sensors for the area of molecular photoionic devices is pointed out. 

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