The effect of light and thermally initiated E-Z isomerization on the anion sensing of two easy synthesized and efficient isatin N-phenylsemicarbazone E-isomer colorimetric sensors Ia and IIa for strongly basic anions were investigated. The photodegradation of E-isomer anion sensors due to light initiated E-Z isomerization during anion sensing may complicate the anion detection, therefore care should be taken when interpreting data for quantitative determination of anions using sensors with the tendency towards E-Z isomerization. However, the photochemical E-Z isomerization efficiency for Ia and IIa is relatively low at ФE-Z < 0.01, and this allows reliable detection of strongly basic anions. Moreover, despite of lower Z-isomer sensitivity, the utilization of both E- and Z-isomer enlarges the detection range for F- or CH3COO- anions valid for Ia and IIa in organic media from approximately 1×10-6-1×10-4 mol dm-3 to 1×10-6-1×10-2 mol dm-3 of F- or CH3COO-. Zero efficiency of both photochemically and thermally initiated back Z-E isomerizations was observed.1
This work is the result of the project implementation: The Competence Center for Intelligent Technologies to Enable Electronization and Informatization of Systems and Services, ITMS 26240220072, supported by the Research & Development Operational Programme funded by the ERDF.
1Jakusová K., Cigáň M., Donovalová J., Gáplovský M., Sokolík R., Gáplovský A., Light initiated E-Z and Z-E isomerization of efficient colorimetric isatinphenylsemicarbazone sensors for anions: Tautomeric equilibrium effect, J. Photochem. Photobiol. A Chem. (2014), accepted manuscript.