Synthesis of pyrazolone based potential fluorescence chemosensor molecules

Pyrazolone chemistry attracts a wide attention due to its various applications in different fields. However, the recognition and detection of metal ions has become an active research topic due to its potential applications in various fields, including environmental studies. In this thesis, it is aimed to synthesize new azo- and bisazo-5-pyrazolone molecules that can show fluorescent chemosensor properties. For this purpose, first, compounds 1 and 2 in the structure of 5-pyrazolone, which are the starting molecules, were synthesized. Then, new azo- and bisazo- 5-pyrazolone structures (1a-d and 2a-d) were obtained by azo-coupling reaction of these compounds with p-anisidine, 2,4-dimethylaniline amines and benzidine, 4,4'-diaminodiphenyl sulfone diamines. Following purification studies, molecular characterizations of the compounds were performed by FTIR, 1H NMR, 13C NMR-APT, HRMS and UV-Vis. spectroscopic methods. Although fluorescent chemosensor studies of newly synthesized structures are not within the scope of the thesis, preliminary experiments have revealed that all molecules show fluorescent properties. However, it was found that the azo-structured molecules showed a colorimetric chemosensory behavior towards the copper(II) ion rather than a fluorescent chemosensor. For this reason, we focused on colorimetric chemosensor studies. In this context, it is working with 14 metal nitrate salts. LOD (limit of detection) and LOQ (limit of quantification) calculations, color reversibility, selectivity for copper(II) ions in all metals, examination of the acidic and basic environment behavior of the sensor, and determination of metal-sensor stoichiometry with Job's plot study are aimed.