A novel series of Zn, Cd and UO complexes of ligands namely 1-[(5-mercapto-1H-1,2,4-triazole-3-ylimino) methyl]naphthalene-2-ol (HL) and [(1H-1,2,4-triazole-3-ylimino) methyl] naphthalene-2-ol (HL) have been prepared and characterized by different analytical and spectral techniques. The stoichiometry, stereochemistry, conductivity measurements and mode of bonding of the complexes have been elucidated. Accurate comparison of the IR spectra of the ligands with their metal chelates proved the involvement of nitrogen atoms of the azomethine group and/or triazole ring in chelation in addition to the deprotonated hydroxyl oxygen. The UV-Vis and molar conductance data supported the octahedral geometry for the metal complexes. TGA technique has been used to study the thermal decomposition way of the metal complexes and the thermo kinetic parameters were estimated. Valuable information is obtained from calculations of molecular parameters using the molecular modeling techniques. The interaction between the metal complexes and CT-DNA has been studied from which the binding constants (k) were calculated. The Schiff bases and their metal chelates have shown potent antimicrobial, antioxidant and antitumor activities. The antitumor activities of the compounds have been tested in vitro against HEPG2 cell line and in silico by the molecular docking analysis with the VEGFR-2 receptor responsible for angiogenesis.

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The new azo compound 5-[3-(1,2,4-triazolyl-azo]-2, 4-dihydroxy-benzaldehyde (TA) and its Schiff bases with 1,3-diaminopropane (TAAP) and 1,6-diaminohexane (TAAH) have been synthesized. The bands of diagnostic importance in the IR and the main signals in 1H NMR spectra are assigned. The electronic absorption spectra in pure organic solvents of different polarity and in buffer solutions of varying pH are investigated. The quantitative description of the solvent effect on the electronic absorption spectra is studied and their acid ionization constants are determined. Also, a new simple and sensitive method for the spectrophotometric microdetermination of Co(II) using these compounds (TA, TAAP and TAAH) as new chromogenic reagents is established. The developed method is successfully used for the determination of trace amounts of cobalt in authentic samples and calculation of the distribution ratio of cobalt adsorbed on bentonite and kaolinite clay minerals. © 2004 Elsevier Ltd. All rights reserved

New seven complexes of N 1 ,N 6 -bis((2-hydroxynaphthalin-1-yl)methinyl)) adipohydrazone (H 2 L) with MnCl 2 •4H 2 O, CoCl 2 •6H 2 O, NiCl 2 •6H 2 O, CuCl 2 •2H 2 O, Cu(NO 3 ) 2 •3H 2 O, CuSO 4 •5H 2 O, and Cu(OAc) 2 •2H 2 O have beenprepared and characterized by the aid of elemental and thermal analyses, spectra (FT-IR, 1 H NMR, MS, UV-Vis, ESR, X-ray powder diffraction), molar conductance and magnetic moment measurements. The XRD results unambiguously confirmed the nano-sized particles of the complexes. The results showed that H 2 L behaves as dibasic tetra-dentate ligand towards the metal ions of interest. The low molar conductance values revealed the non-electrolytic nature for the chelates. The magnetic moment data, UV-Vis and ESR spectra denoted the formation of octahedral geometries for Mn(II) and Ni(II) complexes, whereas Co(II), Cu(II) complexes exhibited tetrahedral arrangement. The activation parameters for the thermal decomposition stages were calculated from TGA curves using Coats-Redfern and Horowitz-Metzger methods. The obtained data were confirmed by 3-D molecular modeling of the ligand and some complexes. The investigated compounds were screened for their antimicrobial activities against different types of organisms and antitumor activities towards human liver Carcinoma (HEPG2) cell to access their potential chemotherapeutic use. The free ligand (H 2 L) exhibited a weak inhibition of cell viability with IC 50 of 11.80 μg/ml, complexes 4, 6 and 7 showed a moderate activity with IC 50 of 5.56, 7.71 and 5.67 μg/ml, whereas complexes 1, 2, 3, and 5 displayed a strong anticancer activity with IC 50 of 4.65, 3.97, 3.30 and 4.84 μg/ml, compared with IC 50 value of 4.73 μg/ml for the doxorubicin (standard cytotoxin drug).

Acetato, chloro and nitrato Cu(II) complexes of a novel azo compound, namely 2,4‐dihydroxy‐5‐[(5‐mercapto‐1H‐1,2,4‐triazole‐3‐yl)diazenyl]benzaldehyde, have been prepared. The stoichiometry, stereochemistry and bonding fashion of these copper chelates were deduced via elemental analyses, spectral methods and conductivity and magnetic measurements. Infrared spectral data confirmed the participation of azo N atom and the deprotonated OH group. UV–visible spectral data and magnetic measurements indicated octahedral stereo‐structure for the acetato and nitrato compounds and square planer for the chloro compound. Thermogravimetric analysis was applied to investigate the thermal degradation of the metal chelates. The thermo‐kinetic parameters were computed. The molecular modeling technique was used to support the predicted geometry of the prepared chelates. The interaction between the Cu(II) complexes and calf thymus DNA was studied using two techniques: absorption and viscosity measurements. The values of binding constant obtained from the absorption spectral method were calculated and found to be 4.23 × 104, 26.93 × 104, 13.01 × 104 and 5.36 × 104 M−1 for ligand and acetato, chloro and nitrato complexes, respectively. The antimicrobial activities were evaluated against various bacterial and fungi strains. The in vitro antitumor efficacy of the synthesized compounds was investigated against the HEPG2 cell line.