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

Abstract A novel bispyrazole derivative 2,6-bis(5-(4-methylphenyl)-1- H -pyrazol-3-yl)pyridine was synthesized and its structure was confirmed by 1 H NMR, FTIR, MS techniques and elemental analysis. The binding interactions of BMPP with Cd 2+ , Co 2+ , Pb 2+ and Cu 2+ ions were investigated in MeOH–H 2 O solution by fluorescence quenching technique at two temperatures (25 and 35 °C). Their quenching constants K SV , binding constants K , binding sites n and thermodynamic parameters (Δ H , Δ G and Δ S ) 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 Δ S -driven.