| Abstrakt: |
The ability of N -(1,3-dioxo-1 H -benzo[de]isoquinolin-2(3 H )-yl)isonicotinamide (naphydrazide) or 2,6-pyridinedicarboxylic acid (2,6-H 2 pdc) individually or as a bi-component system in distinguishing and detecting Fe 3+ or Fe 2+ and Cd 2+ ions was investigated. The use of these molecules as single or bi-component analytes in absorption or emission spectroscopy studies showed that under specific conditions each had their own merits for specific purposes. UV-visible spectroscopic studies of 2,6-H 2 pdc for assessing the interactions with ferrous and ferric ions showed characteristic distinctions. The detection limit for Fe 3+ analysed through UV-visible spectroscopy using naphydrazide was 0.46 μM, whereas it was 1.28 μM using 2,6-H 2 pdc. Naphydrazide together with Fe 3+ allowed distinguishing Cd 2+ ions from Zn 2+ and Fe 2+ ions. The bi-component system was useful for the selective detection of Cd 2+ ions using fluorescence spectroscopy, with a detection limit for Cd 2+ ions of 18.31 μM. The presence of Fe 2+ and Cd 2+ ions in a solution of the bi-component had resulted white-light emission. An analogous compound N , N '-(1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-2,7(1 H ,3 H ,6 H ,8 H )-diyl)diisonicotinamide (binaphydrazide) was found unsuitable for such detections. Two 2,6-pyridinedicarboxylate Fe 3+ complexes possessing protonated naphydrazide or binaphydrazide were prepared and characterised. These complexes were also found unsuitable for the detection of the said ions in solution. Electrochemical studies with the bi-component system showed that cyclic voltammograms could distinguish Fe 3+ or Fe 2+ from Cd 2+ ions.
Competing Interests: There are no conflicts of interest to declare.
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