Synthesis , characterization , thermodynamic and spectroscopic properties for antipyrine - azo complexes

Abstract

This paper involved synthesis of ligand (1,5-dimethyl-2-phenyl-4-((2,3,4-trihydroxy phenyl) diazenyl)-1H-pyrazol-3(2H)-one) by coupling of diazonium salt (4-amino antipyrine ) with pyrogallol in
basic ethanolic media . this ligand characterized means of FTIR ,1H NMR , 13C-NMR and measure melting point ,then prepare three new chelating complexe for ligand with Ag+1 , Cu+2 , Au+4 , and determine the stability by using UV-Vis spectroscopy then their thermodynamic function of complexes formation (standard Gibbs energy ΔGo , standard enthalpy ΔHo and standard entropy ΔSo)for formation of the complexes were obtained from temperature dependence of stability constant using the (Vant Hoff) equation
using UV-Vis and FT-IR spectra techniques ,have solutions which that show red shift the compared with ligand solution ,when their FTIR spectra show many changes ,new band appears ,which were not found in ligand spectrum, while many other bands served changes in shape ,position and in tensity wich are explained by the coordination with metal ione