Fluorescence quenching study of 2,6-bis(5-(4-methylphenyl)-1-H-pyrazol-3-yl)pyridine with metal ions

• Fluorescence quenching of the bis-pyrazole with metal ions.
• KSV, K, ΔH, ΔG and ΔS of BMPP with Cd2+, Co2+, Pb2+ and Cu2+.

A novel bispyrazole derivative 2,6-bis(5-(4-methylphenyl)-1-H-pyrazol-3-yl)pyridine was synthesized and its structure was confirmed by 1H NMR, FTIR, MS techniques and elemental analysis. The binding interactions of BMPP with Cd2+, Co2+, Pb2+ and Cu2+ ions were investigated in MeOH–H2O solution by fluorescence quenching technique at two temperatures (25 and 35 °C). Their quenching constants KSV, binding constants K, binding sites n and thermodynamic parameters (ΔH, ΔG and ΔS) were determined. The results indicated that the metal ions quenched the intrinsic fluorescence of the bispyrazole by forming the bispyrazole–metal complexes and their quenching process was a static quenching mechanism. In addition, the process of interaction was spontaneous and mainly ΔS-driven.

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