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Photophysical Properties of New Pyrazolone Based Azo- Compounds

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New 5-pyrazolone based azo- dyes (25) and a bisazo- dye (6) were synthesized via diazo- coupling reaction with substituted aryl amines. All azo-5-pyrazolone compounds were characterized with the aid of FTIR, UV-Vis., 1H NMR, 13C NMR-APT and, GC-MS or ESI(+)-MS spectroscopic techniques. NMR studies showed that all azo- and bisazo- compounds, are in hydrazo-keto form except compound 5 which is in enol-azo form in solution. FTIR(ATR) studies indicated that compounds 2 and 4 are in azo-keto form, compounds 3 and 6 are in hydrazo-keto form and compound 5 is in enol-azo form in the solid state. All newly synthesized compounds were investigated for their absorption and emission characteristics. Photophysical properties of the solvent polarity effect and acid/base effect on the absorption and emission spectra were evaluated for an azo- (2) and a bisazo- compound (6). All azo-5-pyrazolone compounds showed fluorescence properties and the solvents with different polarities gave rise to shifts in the absorption and emission spectra of 2 and 6. The base addition did not affect the emission spectra while changing the absorption properties of the azo- and bisazo- compounds. Thermal work of 2 and 6 were carried out with TG/DTG technique and the results showed that compound 2 had adequate stability for industrial applications as a fluorescent material.

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We thank the Central Research Laboratory of Ordu University for GC-MS, TG-DTG, and Fluorimetric analyses. A part of this work was supported by Yıldız Technical University, Scientific Research Projects Coordination Department, Project number: YTUAF (2009-01-02-ODAP01).

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Correspondence to Emine Bagdatli.

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This work is dedicated to the lovely memory of Prof. Dr. Zehra Nuket Ocal Sunguroglu.

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Bagdatli, E., Yaman, D. Photophysical Properties of New Pyrazolone Based Azo- Compounds. J Fluoresc 30, 51–61 (2020). https://doi.org/10.1007/s10895-019-02469-y

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  • Pyrazolone
  • Azo- pyrazolone
  • Bisazo- pyrazolone
  • Photophysical properties
  • Thermal analysis