Spectroscopy: the study of DNA cleavage by newly synthesized polydentate macrocyclic ligand and its copper(II) complexes

Synthesis, characterization and biochemical behaviour of macrocyclic complexes of Zn(II) and Co(II) metals

A series of Zn(II) and Co(II) complexes have been synthesized by template condensation of bis(benzil)-4-chloro-1,2-phenylenediamine and bis(benzil)-4-fluoro-1,2-phenylenediamine, respectively, with 4-chloro-1,2-phenylenediamine and 4-fluoro-1,2-phenylenediamine in the presence of transition metal chlorides. The complexes have been characterized by physicochemical and spectroscopic techniques. Based on these studies, an octahedral geometry has been proposed around the metal ions. The newly synthesized ligands and their metal complexes have been screened for antimicrobial and anticancer activities. The in vitro cytotoxicity towards the HeLa cell line has been evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.

Synthesis and characterization of some new Cu(II), Ni(II) and Zn(II) complexes with salicylidene thiosemicarbazones: antibacterial, antifungal and in vitro antileukemia activity

Thirty two new Cu(II), Ni(II) and Zn(II) complexes (1–32) with salicylidene thiosemicarbazones (H₂L¹–H₂L¹⁰) were synthesized. Salicylidene thiosemicarbazones, of general formula (X)N-NH-C(S)-NH(Y), were prepared through the condensation reaction of 2-hydroxybenzaldehyde and its derivatives (X) with thiosemicarbazide or 4-phenylthiosemicarbazide (Y = H, C₆H₅). The characterization of the new formed compounds was done by ¹H-NMR, ¹³C-NMR, IR spectroscopy, elemental analysis, magnetochemical, thermoanalytical and molar conductance measurements. In addition, the structure of the complex 5 has been determined by X-ray diffraction method. All ligands and metal complexes were tested as inhibitors of human leukemia (HL-60) cells growth and antibacterial and antifungal activities.

Spectral, thermal and electrochemical investigation of carbohydrazone derived ionophore as Fe(III) ion selective electrode

Dibenzoylmethane bis(carbohydrazone) (BMBC) has been synthesized and structurally characterized on the basis of IR, (1)H NMR, mass, UV spectra and thermogravimetric analyses. BMBC has been analysed electrochemically and explored as new N, N Schiff base. It plays the role of an excellent ion carrier in the construction of iron(III) ion selective membrane sensor. This sensor shows very good selectivity and sensitivity towards iron ion over a wide variety of cations, including alkali, alkaline earth, transition and heavy metal ions. The response mechanism was discussed in the view of UV-spectroscopy and Electrochemical Impedance Spectroscopy (EIS). The proposed sensor was successfully used for the determination of iron in different samples.

New hexadentate macrocyclic ligand and their copper(II) and nickel(II) complexes: Spectral, magnetic, electrochemical, thermal, molecular modeling and antimicrobial studies

Ni(II) and Cu(II) complexes were synthesized with a hexadentate macrocyclic ligand [3,4,8,9tetraoxo-2,5,7,10tetraaza-1,6dithio-(3,4,8,9) dipyridinedodecane(L)] and characterized by elemental analysis, molar conductance measurements, mass, NMR, IR, electronic, EPR spectral, thermal and molecular modeling studies. All the complexes are 1:2 electrolytes in nature and may be formulated as [M(L)]X(2) [where, M=Ni(II) and Cu(II) and X=Cl(-), NO(3)(-), ½SO(4)(2-), CH(3)COO(-)]. On the basis of IR, electronic and EPR spectral studies an octahedral geometry has been assigned for Ni(II) complexes and tetragonal geometry for Cu(II) complexes. The antimicrobial activities and LD(50) values of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against two different species of bacteria and plant pathogenic fungi.

Synthesis, spectroscopic characterization, DNA interaction and antibacterial study of metal complexes of tetraazamacrocyclic Schiff base

The template condensation reaction between benzil and 3,4-diaminotoulene resulted mononuclear 12-membered tetraimine macrocyclic complexes of the type, [MLCl(2)] [M=Co(II), Ni(II), Cu(II) and Zn(II)]. The synthesized complexes have been characterized on the basis of the results of elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz. FT-IR, (1)H and (13)C NMR, FAB mass, UV-vis and EPR. An octahedral geometry has been envisaged for all these complexes, while a distorted octahedral geometry has been noticed for Cu(II) complex. Low conductivity data of all these complexes suggest their non-ionic nature. The interactive studies of these complexes with calf thymus DNA showed that the complexes are avid binders of calf thymus DNA. The in vitro antibacterial studies of these complexes screened against pathogenic bacteria proved them as growth inhibiting agents.

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.

Synthesis and thermal studies of tetraaza macrocylic ligand and its transition metal complexes. DNA binding affinity of copper complex

A Tetraaza Macrocylic Ligand (H2L) and its complexes, [Cd(H2L)(OH2)2](NO3)(2)·1/2OH2 (I), [Co(H2L)(OH2)](NO3)(2)·1/2OH2 (II), [Cu(H2L)(NO3)2]·3/2OH2 (III) and [Ni(H2L)(NO3)(OH2)]NO3·OH2 (IV), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H NMR, UV-vis, FT-IR and mass spectroscopy. All results confirm that the prepared compounds have 1:1 metal-to-ligand stoichiometry, octahedral configuration and the ligand behaves as a neutral tetradendate towards the metal ions. [CdL(OH2)2] (V), [CoL(OH2)2] (VI), [CuL(OH2)2] (VII) and [Ni(H2L)(NO3)2] (VIII) were synthesized pyrolytically in solid state from corresponding compounds (I-IV). Analytical results of complexes (V-VIII) show that the ligand behaves either as a neutral tetradendate or dianionic tetradentate ligand towards the metal ions. The binding of H2L and its copper complex (III) to DNA has been investigated by ultraviolet absorption spectroscopy. The experiments indicate that H2L and its copper complex (III) can bind to DNA through an intercalative mode. The H2L and its copper complex (III) exhibited anti-tumor activity against Ehrlich Acites Carcinoma (E.A.C) at the concentration of 100 μg/ml.