Synthesis, characterization and biological study on Cr(3+), ZrO(2+), HfO(2+) and UO(2)(2+) complexes of oxalohydrazide and bis(3-hydroxyimino)butan-2-ylidene)-oxalohydrazide

Chelation, spectroscopic characterization, biological activity and crystal structure of 2,3-butanedione isonicotinylhydrazone: Determination of Zr(4+) after flotation separation

New metal complexes of Co(II), Ni(II) Cu(II), Zn(II), Cd(II), Pd(II) and Hg(II) with 2,3-butanedione isonicotinylhydrazone [BINH] have been prepared and investigated. Single crystal for BINH is grown and solved as orthorhombic with P 21 21 2 space group. The formula of the ligand was assigned based on the elemental analysis, mass spectra and conductivity measurements. The complexes assigned the formulae [M(BINH-H)Cl]⋅nH2O (MCo(II), Ni(II), Cu(II), Zn(II); n=0 or 1); [Hg(BINH-H)(H2O)2Cl]; [Cd(BINH)Cl2]⋅2H2O and [Pd(BINH)Cl2]⋅H2O. All complexes are nonelectrolytes. BINH acts as a tridentate ligand in [M(BINH-H)Cl]⋅nH2O and [Hg(BINH-H)(H2O)2Cl] coordinating through COketonic, COamedic and CNhy and as a neutral bidentate through COketonic and CNhy in [Cd(BINH)Cl2]⋅2H2O and [Pd(BINH)Cl2]⋅H2O; the pyridine nitrogen has no rule in coordination. The data are supported by NMR ((1)H and (13)C) spectra. The magnetic moments and electronic spectra provide a tetrahedral structure for the Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes; square-planar for the Pd(II) complex and octahedral for the Hg(II) complex. The TGA of the complexes depicted the outer and inner water molecules as well as the final residue. The cobalt and cadmium complexes ended with the metal while the Cu(II), Zn(II) and Pd(II) complexes ended with complex species. [Hg(BINH-H)(H2O)2Cl] has no residue. The ligand is inactive against all tested organisms except for Bacillus thuringiensis. The Hg(II) complex is found more active than the other complexes. The flotation technique is found applicable for the separation of micro amount (10ppm) of Zr(4+) using 10ppm of BINH and 1×10(-5)molL(-1) of oleic acid at pH 6 with efficiency of 98% with no interferences.

Synthesis, characterization and biological activity of 2-acetylpyridine-α naphthoxyacetylhydrazone and its metal complexes [corrected]

A new series of complexes of Ni(II), Co(II), Cu(II), Cd(II), Mn(II), Hg(II) and UO2(2+) derived from 2-acetylpyridine-α-naphthoxyacetylhydrazone (HA2PNA) have been prepared and characterized by elemental analyses, spectral (IR, UV-visible, ESR and (1)H NMR) as well as magnetic and thermal measurements. The data revealed that the ligand acts as neutral NO, NN and NNO or mono-negative NNO chelate. On the basis of electronic spectral and magnetic moment data, an octahedral geometry is suggested for Mn(II), Co(II), Ni(II) and UO2(2+) complexes and a square planar arrangement for Cu(II) complex. The bond length, bond angle, HOMO, LUMO, dipole moment and charges on the atoms have been calculated to confirm the geometry of the ligand and the investigated complexes. The kinetic parameters were determined for thermal degradation stages of some complexes using Coats-Redfern and Horowitz-Metzger methods. Also, the ligand and its complexes were screened against antibacterial, antioxidant using DPPH radical and antitumor activities using in vitro Ehrlich ascites assay.

Synthesis, characterization, biological activity of binuclear Co(II), Cu(II) and mononuclear Ni(II) complexes of bulky multi-dentate thiosemicarbazide

The chelation behavior of 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarbonyl) bis (N-ethylhydrazine-1-carbothioamide) (H6ETS)(1) towards Co(2+), Ni(2+)and Cu(2+) have been studied. The spectral data revealed that the ligand acts as a bi- and/or mono-negative multi-dentate. The isolated Ni(II) and Cu(II) complexes are square-planar while the Co(II) is tetrahedral. EPR spectrum of Cu(II) complex confirmed simulated an axial spin-Hamiltonian exhibiting a four-line pattern with nitrogen super-hyperfine couplings originating from imine hydrazinic nitrogen atoms and possess a significant amount of tetrahedral distortion leading to a pseudo-square-planar geometry with unpaired electron has d(x(2)-y(2)) ground state. Also, the thermal behavior and kinetic parameters were determined. Furthermore, the title compounds were investigated for their antibacterial activity using inhibition zone diameter and for DNA degradation, superoxide-scavenging activity as well as hydroxyl radicals that generated by the oxidation of cytochrome c in L-ascorbic acid/CuSO4-cytochrome c system.

Synthesis, spectroscopic characterization and antimicrobial activity of binuclear metal complexes of a new asymmetrical Schiff base ligand: DNA binding affinity of copper(II) complexes

The 1:1 condensation of o-acetoacetylphenol and 1,2-diaminopropane under condition of high dilution gives the mono-condensed Schiff base, (E)-3-(1-aminopropan-2-ylimino)-1-(2-hydroxyphenyl)butan-1-one. The mono-condensed Schiff base has been used for further condensation with isatin to obtain the new asymmetrical dicompartmental Schiff base ligand, (E)-3-(2-((E)-4-(2-hydroxyphenyl)-4-oxobutan-2-ylideneamino) propylimino)indolin-2-one (H3L) with a N2O3 donor set. Reactions of the ligand with metal salts give a series of new binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H and (13)C NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The analytical and spectroscopic tools showed that the complexes can be formulated as: [(HL)(VO)2(SO4)(H2O)]·4H2O, [(HL)Fe2Cl4(H2O)3]·EtOH, [(HL)Fe2(ox)Cl2(H2O)3]·2H2O, [(L)M2(OAc)(H2O)m]·nH2O; M=Co, Ni or Cu, m=4, 0 and n=2, 3, [(HL)Cu2Cl]Cl·6H2O and [(L)(UO2)2(OAc)(H2O)3]·6H2O. The metal complexes exhibited octahedral geometrical arrangements except copper complexes that exhibited tetrahedral geometries and uranyl complex in which the metal ion is octa-coordinated. The Schiff base and its metal complexes were evaluated for antimicrobial activity against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli) and fungi (Candida albicans and Aspergillus flavus). The ligand and some of its complexes were found to be biologically active. The DNA-binding properties of the copper complexes (6 and 7) have been investigated by electronic absorption, fluorescence and viscosity measurements. The results obtained indicate that these complexes bind to DNA via an intercalation binding mode with an intrinsic binding constant, Kb of 1.34×10(4) and 2.5×10(4) M(-1), respectively.

Oxidative stress and antimicrobial activity of chromium(III) and ruthenium(II) complexes on Staphylococcus aureus and Escherichia coli

The prevalence of antibiotic resistance has resulted in the need for new approaches to be developed to combat previously easily treatable infections. The main aim of this work was to establish the potential of the synthetic α-diimine chromium(III) and ruthenium(II) complexes (where the α-diimine ligands are bpy = 2,2-bipyridine, phen = 1,10-phenanthroline, and dppz = dipyrido[3,2-a:2′,3′-c]-phenazine) like [Cr(phen)₃]³⁺, [Cr(phen)₂(dppz)]³⁺, [Ru(phen)₃]²⁺, and [Ru(bpy)₃]²⁺ as antibacterial agents by generating oxidative stress. The [Cr(phen)₃]³⁺ and [Cr(phen)₂(dppz)]³⁺ complexes showed activity against Gram positive and Gram negative bacteria with minimum inhibitory concentrations (MICs) ranging from 0.125 μg/mL to 1 μg/mL, while [Ru(phen)₃]²⁺ and [Ru(bpy)₃]²⁺ do not exhibit antimicrobial activity against the two bacterial genera studied at the concentration range used. When ciprofloxacin was combined with [Cr(phen)₃]³⁺ for the inhibition of Staphylococcus aureus and Escherichia coli, an important synergistic effect was observed, FIC 0.066 for S. aureus and FIC 0.064 for E. coli. The work described here shows that chromium(III) complexes are bactericidal for S. aureus and E. coli. Our results indicate that α-diimine chromium(III) complexes may be interesting to open new paths for metallodrug chemotherapy against different bacterial genera since some of these complexes have been found to exhibit remarkable antibacterial activities.

Comparative studies of mononuclear Ni(II) and UO2(II) complexes having bifunctional coordinated groups: synthesis, thermal analysis, X-ray diffraction, surface morphology studies and biological evaluation

Two Schiff base ligands derived from condensation of phthalaldehyde and o-phenylenediamine in 1:2 (L(1)) and 2:1 (L(2)) having bifunctional coordinated groups (NH(2) and CHO groups, respectively) and their metal complexes with Ni(II) and UO(2)(II) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibilities and spectral data (IR, (1)H NMR, mass and solid reflectance) as well as thermal, XRPD and SEM analysis. The formula [Ni(L(1))Cl(2)]·2.5H(2)O, [UO(2)(L(1))(NO(3))(2)]·2H(2)O, [Ni(L(2))Cl(2)]·1.5H(2)O and [UO(2)(L(2))(NO(3))(2)] have been suggested for the complexes. The vibrational spectral data show that the ligands behave as neutral ligands and coordinated to the metal ions in a tetradentate manner. The Ni(II) complexes are six coordinate with octahedral geometry and the ligand field parameters: D(q), B, β and LFSE were calculated while, UO(2)(II) complexes are eight coordinate with dodecahedral geometry and the force constant, F(U-O) and bond length, R(U-O) were calculated. The thermal decomposition of complexes ended with metal chloride/nitrate as a final product and the highest thermal stability is displayed by [UO(2)(L(2))(NO(3))(2)] complex. The X-ray powder diffraction data revealed the formation of nano sized crystalline complexes. The SEM analysis provides the morphology of the synthesized compounds and SEM image of [UO(2)(L(2))(NO(3))(2)] complex exhibits nano rod structure. The growth-inhibiting potential of the ligands and their complexes has been assessed against a variety of bacterial and fungal strains.