Oxacyanine dyes

Figure 4. Combination of energy transfer and photoinitiated electron transfer for signal amplification. The transient radical absorption (sec Figure 3) generated by excitation of the oxacyanine dye with UV radiation (366 nm) acts as energy acceptor and quenches partly the red emission at 590 nm of the monolayer of Vt.ti -dioctadecylindocarhocyanine excited simultaneously at 545 nm. The periodical irradiation of the complex system with the UV radiation causes a modulation of the indocarbocyanine fluorescence.

To illustrate the kind of systems that have been achieved since that time, we present two examples. The first one uses two cyanine dyes carrying long alkyl chains, the oxacyanine dye (23) and the thiocyanine dye (24). The benzoxazole ring in compound (23) has an absorption band in the UV and it fluoresces in the blue. The benzothiazole ring in compound (24)... 

Potentiometry on the Water-Nitrobenzene Interface in the Presence of Oxacyanine Dyes... 

Concluding Remarks on Potentiometry. Due to the unique characteristics of the liquid-liquid interface system, factors in addition to the concentration of analyte ion must be considered in potentiometric studies. These factors include the nature and concentration of the supporting electrolytes and the relative volume of the phases in contact. Numerical solutions of the theoretical relationship derived by Hung (15) are useful to predict the effect of such factors as volume of the phases and concentration of added ions. Experimental results with an oxacyanine dye in a water-nitrobenzene system show a linear response in the 10 3-10 5-mol/L concentration range, which corresponds to a 120-mV dynamic range of these dyes for use as potential sensors. This response agrees with measurements on biological... 

This new emission was also detected in other cyanines [16,88], such as 2,2 -cyanine [88b] and oxacyanine dyes [88a]. Energy studies revealed a supralinear dependence on laser energy. 

Arden and Fromherz [51-53] have reported elegant work involving mono-layers of surfactants transferred to electrodes by the Langmuir-Blodgett method. Some results are shown in Figure 28.10. Two separate cationic dyes, thiacyanine (A) and oxacyanine (D), were synthesized with C18 alkyl chains, so that they would form oriented monolayers on water-air interfaces. By standard techniques, these were transferred alternatively or in sequence to n-ln203 electrodes, as... 

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