Molecular Modeling of 4-Ethyl-1-(pyridin-2-yl)thiosemicarbazide and its Cu(II) Complex Utilized for Separation of Cu(II) from Water Samples

Abstract

Molecular modeling and spectroscopic characterization of 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide (HEPTS) and its complex [Cu4(EPTS)3(H2O)(EtOH)(OH)Cl4]2H2O are investigated. Structural, electronic, and vibrational features are discussed, and assignments were proposed on the basis of semiempirical quantum mechanics calculations (ZINDO/S and PM3). The simulated IR and UV−vis spectra are in reasonable accordance with the experimental data. Moreover, a rapid and selective procedure for extraction of Cu(II) at trace levels using silica gel immobilized with 4-ethyl-1-(pyridin-2-yl)thiosemicarbazide is proposed. The Cu(II)−EPTS complex was easily adsorbed on silica gel and eluted with 5.0 M HNO3. The pH, amount of HEPTS, sample volume, and detection limit were evaluated in synthetic, spiked, and tap water samples. The interfering effect of some cations and anions on the recovery of Cu(II) was studied. Under optimum conditions, the recovery of Cu(II) ions was (97 ± 1) % at the 95 % confidence level. The adsorption isotherm was studied, and the binding equilibrium constant and the adsorption capacity were 3.585 L·mg−1 and 520.8 μg·g−1, respectively. The detection limit and relative standard deviation were 4 ng·L−1 and 1.5 %, respectively. The proposed method was applied for the separation of Cu(II) ions from water samples.

Chelation activity of N'1,N'6-bis((E)-3,4-dihydroxybenzylidene)adipohydrazide towards some transition metal ions

“…In continuation of our ongoing studies on dihydrazone ligands [14][15][16][17][18][19][20][21], we have synthesized and characterized new metal complexes of Zr(IV), Co(II), Ni(II), Cu(II), and Cd(II) ions with N'1,N'6-bis((E)-3,4-dihydroxybenzylidene)adipohydrazide.…”

Adsorptive Removal of Cu(II) Ions from Aqueous Media onto 4-Ethyl Thiosemicarbazide Intercalated Organophilic Calcined Hydrotalcite

“…3 Due to their good complexing property, thiosemicarbazides have been subject of many studies. 4,5 Thiosemicarbazide is basically a bidentate ligand with potential sulfur and nitrogen donors. Its multifunctional coordination centers and formation of biologically important metal complexes make it noteworthy.…”