Synthesis, spectroscopic and potentiometric studies on a silver [I] complex derived from a new BIS [thiosemicarbazone]

A new reagent, [2E, 2Z]2,2-[3[E]-[2-hydroxyphenyl] diazenyl] pentane-2,4-diylidene] bis [hydrazinecarbothioamide] [OPTS] was synthesized and studied. Acid-base, spectrophotometric properties of OPTS were studied in 50% ethanol-water mixture solutions at pH 3-11. Ionization constants of the reagent OPTS have been determined by a spectrophotometric and potentiometric titrations: pK[1]=9.60 +/- 0.02; pK[2]= 10.45 +/- 0.05 in its computational and graphical versions at an ionic strength 0.1 M Na10[4]. The stability constants of the Ag-OPTS are logK[1]=4.55 +/- 0.04 and 10gK[2]=3.92 +/- 0.05. The reaction of Ag [I] with OPTS gives a mononuclear complex in 50% ethanol water mixture solution with lambda[max]=462 nm at pH=8.1. The effects of foreign ions and masking agents on the determination of Ag [I] with the new reagent are studied. The mono complex obeys the Beer's law in the Ag [I] concentration range 1.1-17 mg/25ml. Molar absorption coefficients were determined. In this paper, we report the synthesis of the novel Ag [l] complexes with OPTS. The complexes were characterized by UV-Vis and IR spectroscopy, elemental analysis, molar conductivity and thermal decomposition

Studies on the binary and ternary complexes of mercury [II] with gallic acid and adrenaline

The interaction of mercury[II] ions with gallic acid [3,4,5-trihydroxybenzoic acid] [GAL] and adrenaline [epinephrine] [1-[3,4-dihydroxyphenyl]-2-methylaminoethanol] [ADR] were investigated by potentiometric and optical means. The stoichiometries and stability constants of the binary and ternary complexes have been determined pH-metrically in aqueous solution at 25°C and in ionic strength 0.1 M [NaNO3]. The complex formation equilibria involving adrenaline were characterized. The equilibrium Hg[GAL]2+Hg[ADR]2 2Hg[GAL][ADR], the corresponding constant is logX=4.22. The constant due to delta log k[Hg]= log k[Hg] [GAL] [Hg] [GAL] [ADR] - log k [Hg] [HG] [ADR] is 0.75. The results indicate that the overall ratio of the ternary complex Hg[GAL][ADR] is 1:1:1 and the mixed-ligand complex is more stable than one expected from purely statistical reasons. UV-Vis spectroscopy gave additional support to the results. There is a strong evidance from FT-IR spectrum that adrenaline chelates by the phenolic groups