Synthesis, spectral characterization and eukaryotic DNA degradation of thiosemicarbazones and their platinum(IV) complexes

Spectral studies on a series of metal ion complexes derived from pyrimidine nucleus, TEM, biological and γ-irradiation effect

A series of thiouracil complexes was prepared, all the prepared compounds are investigated by all possible tools. The ligand coordinates towards two central atoms as a neutral hexadentate mode. The octahedral structure was proposed with Ni(II), Pt(IV) and UO2(II) complexes. Square-pyramidal and square planar with VO(II) and Pd(II) complexes, respectively. VO(II) complex was irradiated by using Gamma radiation to through a light on the probability of geometry changes with the effect of radiation. The parameters calculated from ESR spectra before and after γ-irradiation reflect the rigidity of the complex towards the effect. Such may discuss the unaffected biological behavior before and after irradiation. XRD patterns were carried out to emphasis on the nature of the particles and the purity of products. The ligand, Pt(IV) and Pd(II) are found in nanometer range. TEM is a sensitive tool used to justify on the microstructure and surface morphology. All the investigated compounds are in nanorange. TG curves reflect a lower thermal stability of all investigated complexes due to the presence of water of crystallization. Finally, a toxic effect was observed with all investigated complexes towards Gram positive bacterium as well as a resistant behavior was observed with Gram negative bacteria.

Synthesis, spectral, electrochemical and X-ray single crystal studies on Ni(II) and Co(II) complexes derived from 1-benzoyl-3-(4-methylpyridin-2-yl) thiourea

1-Benzoyl-3-(4-methylpyridin-2-yl) thiourea ligand was coordinated with Ni(II) and Co(II) perchlorate salts to isolate complexes. All the prepared compounds are deliberately investigated by all possible spectral tools. A comparative study for IR spectra reveals the neutral bidentate coordinating nature of the ligand towards the two metal ions. The UV/Vis spectra of the complexes display d-d transition bands proposed an octahedral geometry for the complexes. MS analysis data are concerned especially with the base peak which is corresponding to C28H25N6O2S2 M ion. The fragmentation patterns are relatively matched with each others. Electrochemical studies were carried out using platinum wire and Ag/AgNO3 as counter and reference electrodes, respectively. The data reflect the irreversible nature of the electrode couple and showed two successive one electron transfer process. X-ray single crystal studies are used to verifying the octahedral geometry proposed as well as calculating crystal parameters beside the structural refinements.

Spectroscopic evaluation for VO(II), Ni(II), Pd(II) and Cu(II) complexes derived from thiosemicarbazide: a special emphasis on EPR study and DNA cleavage

Some thiosemicarbazide complexes were prepared and deliberately investigated by all allowed tools. The ligand coordinates as a mono negative bidentate towards VO(II) and Ni(II) as well as a neutral bidentate towards Pd(II) and Cu(II) ions. Electronic spectral data beside the magnetic measurements facilitate the structural geometry proposal. EPR spectra of Cu(II) and VO(II) complexes were recorded in their solid state. Spin Hamiltonian parameters and molecular orbital coefficient for Cu(II) and VO(II) complexes were calculated and supporting the octahedral geometry of Cu(II) complex and a square pyramidal for VO(II) one. The biological activity investigation was studied by the use of all prepared compounds. The VO(II) and Cu(II) complexes display the susceptible biotoxicity against a gram-positive bacterium. Also, Cu(II) complex displays the same toxicity against gram-negative bacteria used. The effect of all compounds on DNA were photographed. A successive degradation for the DNA target was observed with Pd(II) and Ni(II) complexes beside their original ligand.

Synthesis, characterization and thermal studies of binary and/or mixed ligand complexes of Cd(II), Cu(II), Ni(II) and Co(III) based on 2-(Hydroxybenzylidene) thiosemicarbazone: DNA binding affinity of binary Cu(II) complex

A new series of metal complexes of Cd(II), Cu(II), Ni(II) and Co(III) with Schiff base ligand, H(2)L, 2-(Hydroxybenzylidene) thiosemicarbazone were synthesized. The mixed ligand complexes were prepared by using glycine (Gly), 2-aminopyridine (2-Ampy) and 1,10-phenanthroline (Phen) as secondary ligands. The structure of these complexes was identified and confirmed by elemental analysis, molar conductivity, UV-Vis, FT-IR and (1)H NMR spectroscopy and magnetic moment measurements as well as TG-DSC technique. The discussions of the prepared complexes indicate that the ligand behaves as a monoanionic tridentate ligand through ONS donor sites. Thermal studies suggested a mechanism for the degradation of the metal complexes as a function of temperature supporting the chelation modes and showed the possibility of obtaining new complexes pyrolytically in the solid state which cannot be synthesized from the solution. The absorption studies support that the binary Cu(II) complex exhibits a significant binding affinity to HS-DNA through intercalative mode.

Ligational behavior of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands towards VO(IV), Ce(III), Th(IV) and UO2(VI) ions: synthesis, structural characterization and biological studies

Mono- and binuclear VO(IV), Ce(III), Th(IV) and UO(2)(VI) complexes of thiosemicarbazone, semicarbazone and thiocarbohydrazone ligands derived from 4,6-diacetylresorcinol were synthesized. The structures of these complexes were elucidated by elemental analyses, IR, UV-vis, ESR, (1)H NMR and mass spectra as well as conductivity and magnetic susceptibility measurements and thermal analyses. The thiosemicarbazone (H(4)L(1)) and the semicarbazone (H(4)L(2)) ligands behave as dibasic pentadentate ligands in case of VO(IV) and UO(2)(VI) complexes, tribasic pentadentate in case of Ce(III) complexes and monobasic pentadentate in case of Th(IV) complexes. However, the thiocarbohydrazone ligand (H(3)L(3)) acts as a monobasic tridentate ligand in all complexes except the VO(IV) complex in which it acts as a dibasic tridentate ligand. The antibacterial and antifungal activities were also tested against Rhizobium bacteria and Fusarium-Oxysporium fungus. The metal complexes of H(4)L(1) ligand showed a higher antibacterial effect than the free ligand while the other ligands (H(4)L(2) and H(3)L(3)) showed a higher effect than their metal complexes. The antifungal effect of all metal complexes is lower than the free ligands.

Synthesis and spectral feature of benzophenone-substituted thiosemicarbazones and their Ni(II) and Cu(II) complexes

The ligational behavior of 2-hydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone N-substituted thiosemicarbazones towards Ni(II) and Cu(II) ions has been investigated. The isolated complexes were identified by elemental analyses, molar conductance, magnetic moment, IR, UV-vis and ESR spectral studies. The IR spectra indicated that the investigated thiosemicarbazones lost the N(2) proton or the N(2) and OH protons and act as mononegative or binegative tridentate ligands. The ligands containing methoxy group facilitate the deprotonation of OH by resonance more than the SH. Most of the Ni(II) complexes measured subnormal magnetic moments due to square-planar+tetrahedral configuration and supported by the electronic spectra. The percentage of square-planar to tetrahedral was calculated and found in agreement with the ligand splitting energy (10Dq). Also, Cu(II) complexes measured subnormal values due to the interaction between copper centers; the lower the value the higher the interaction. It was found that the substitutent has a noticeable effect on the distortion of the complex. The ESR spectra of some solid Cu(II) complexes at room temperature exhibit g(parallel)>g( perpendicular)>2.0023 confirming a square-planar structure.