Synthesis and Identification of novel azo-1,3,4-Thiadiazole Derivative and using to Spectrophotometric Determination for some of Transition metal Complexes

This search includes synthesis of ligand by a two-step, the first react between 4-hydroxy benzaoic acid and thiosemicarbazide to form compound (1) [4-(5-amino-1, 3, 4-thiadiazol-2-yl) phenol], the second step is coupling of diazonium salt [5-(4-hydroxyphenyl)-1, 3, 4-thiadiazole-2-diazonium] with 2-hydroxy-5sulfobenzoic acid in basic ethanolic media to get compound (2) [(E)-2-hydroxy-3-((5-(4-hydroxyphenyl)-1, 3, 4thiadiazol-2-yl) diazenyl)-5-sulfobenzoic acid] which characterized by FT-IR,¹H NMR and ¹³C-NMR, after that used for the spectrophotometric determination of cadmium Cd (II) and lead Pb (II). This method was simple, rapid, sensitive, and selective for reaction between cadmium and lead with the reagent. The maximum absorbance observed at 450 nm and 495 nm for Cd(II) and Pb(II) respectively. The molar absorptivity and sandell's sensitivity for cadmium (II) and lead (II) complexes are 4.5077×10⁻⁴, 2.9709× 10⁴ L.mol⁻¹. cm⁻¹ and 0.0212, 0.0353μg/cm² respectively. The stability constant of 1:2 [M:L] complexes of Cd(II) and Pb(II) are 3.13 × 10⁵ and 1.45 × 10⁵ L.mol⁻¹ respectively. The linear range of 0.1–9 μg mL⁻¹, 0.2–12 μg mL⁻¹ along with limit of detection 0.059 μg mL⁻¹, 0.102 μg mL⁻¹, relative standard deviation for seven replication measurements (5 μg Cd mL⁻¹ and 5 μg Pb mL⁻¹) of (0.059%) and (0.102%),and the recovery range of (98.6) and (99.2) were obtained for Cd(II) and Pb(II) ions respectively.