A palladium(II) complex with the Schiff base 4-chloro-2-(N-ethyliminomethyl)-phenol: Synthesis, structural characterization, and in vitro and in silico biological activity studies.

The synthesis and characterization of the Pd(II) complex of the formula [Pd(L)2] 1 with the Schiff base 4-chloro-2-(N-ethyliminomethyl)-phenol (HL) as derived in situ via the condensation reaction of 5-chloro-salicylaldehyde and ethylamine was undertaken. The structure of 1 was verified by single-crystal X-ray crystallography. The ability of 1 to interact with calf-thymus (CT) DNA was studied by UV-vis and viscosity experiments, and its ability to displace ethidium bromide (EB) from the DNA-EB conjugate was revealed by fluorescence spectroscopy. It was found that intercalation is the most possible mode of interaction with CT DNA. Additionally, DNA electrophoretic mobility experiments showed that 1 interacts with the plasmid pBluescript SK(+) (pDNA) as proved by the formation of unusual mobility DNA bands and degradation of relaxed pDNA at concentration of 5 mM. The interaction of 1 with human (HSA) and bovine serum albumin (BSA) was monitored revealing its reversible binding to albumins. The complex showed noteworthy antimicrobial activity against one (Bacillus subtilis) of the five tested bacteria. In order to explain the described in vitro activity of the compound, we adopted molecular docking studies on the crystal structure of HSA, BSA, CT DNA and DNA-gyrase. Furthermore, in silico predictive tools have been employed to study the properties of the complex. The in silico studies are adopted on a multitude of proteins involved in cancer growth, as well as prediction of drug-induced changes of gene expression profile, protein- and mRNA-based prediction results, prediction of sites of metabolism, cytotoxicity for cancer cell lines, etc.

Palladium(II) complexes with salicylaldehyde ligands: Synthesis, characterization, structure, in vitro and in silico study of the interaction with calf-thymus DNA and albumins.

The synthesis and characterization of four palladium(II) complexes with substituted salicylaldehydes (X-saloH) having the general formula [Pd(X-salo)2] was undertaken. The complexes are formulated as [Pd(3-OCH3-salo)2] 1, [Pd(5-NO2-salo)2] 2, [Pd(5-Cl-salo)2] 3, and [Pd(5-Br-salo)2] 4. The structure of complex 1 was verified by single-crystal X-ray crystallography. Spectroscopic (UV-vis), and physicochemical (viscosity measurements) techniques were employed in order to study the binding of the complexes with calf-thymus (CT) DNA, while ethidium bromide (EB) displacement studies, performed by fluorescence emission spectroscopy, revealed the ability of the complexes to displace the DNA-bound EB. Intercalation is the most possible mode of interaction of the complexes with CT DNA. The interaction of the complexes with bovine (BSA) and human (HSA) serum albumin proteins was studied by fluorescence emission spectroscopy and the relatively high binding constants revealed the reversible binding of the complexes to the albumins. Molecular docking simulations on the crystal structure of HSA, BSA and CT DNA were employed in order to study in silico the ability of the studied complexes 1-4 to bind to these target macromolecules.

Ni(II) complexes with 2,2-dipyridylamine and salicylaldehydes: Synthesis, crystal structure and interaction with calf-thymus DNA and albumins.

The synthesis of four cationic mixed-ligand Ni(II) complexes with 2,2'-dipyridylamine (dpamH) and substituted salicylaldehydes (X-saloH) was undertaken in an effort to discover new biologically active compounds. The complexes with the general formula [Ni(dpamH)2(X-salo)]Cl, 3-6, namely [Ni(dpamH)2(5-Cl-salo)]Cl, 3, [Ni(dpamH)2(5-Br-salo)]Cl, 4, [Ni(dpamH)2(5-CH3-salo)]Cl, 5, and [Ni(dpamH)2(3-OCH3-salo)]Cl·CH3OH, 6, were characterized by elemental analyses, FT-IR and UV-vis spectroscopy, magnetic and conductivity measurements. In addition, two analogous nickel-salicylaldehydato complexes in the absence of dpamH were prepared and characterized as [Ni(5-Cl-salo)2(CH3OH)2], 1 and [Ni(5-Br-salo)2(CH3OH)2], 2. The structures of complexes 1-6 were determined by X-ray crystallography revealing octahedral coordination of nickel (II) and monomeric nature of the compounds. Spectroscopic (UV-vis), electrochemical (cyclic voltammetry) and physicochemical (viscosity measurements) techniques were employed in order to study the binding mode and strength of the complexes to calf-thymus (CT) DNA, while competitive studies with ethidium bromide (EB), performed by fluorescence spectroscopy, revealed the ability of the complexes to displace the DNA-bound EB. The complexes bind to DNA probably via intercalation exhibiting high DNA-binding constants. For the cationic complexes 3-6, the coexistence of an electrostatic interaction with CT DNA may be also suggested. The interaction of the complexes with serum albumins was studied by fluorescence emission spectroscopy and the determined binding constants exhibit relative high values.

Interaction of dinuclear cadmium(II) 5-Cl-salicylaldehyde complexes with calf-thymus DNA.

Five dinuclear Cd(II) complexes with the anion of 5-Cl-salicylaldehyde (5-Cl-saloH) were synthesized in the absence or presence of the α-diimines: 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (neoc) or 2,2'-dipyridylamine (dpamH) and characterized as [Cd(5-Cl-salo)2(CH3OH)]2 (1), [Cd(5-Cl-salo)2(bipy)]2 (2), [Cd(5-Cl-salo)2(phen)]2 (3), [Cd(5-Cl-salo)(neoc)(ONO2)]2 (4) and [Cd(5-Cl-salo)(dpamΗ)(ONO2)]2 (5). The complexes were characterized by spectroscopic techniques (IR, UV-vis, (1)H-NMR and (13)C-NMR), elemental analysis and molar conductivity measurements. The structures of four complexes (1-3 and 5) were determined by X-ray crystallography, providing all three possible coordination modes of the ligand 5-Cl-salicylaldehyde, i.e. bidentate or tridentate chelating and/or bridging mode. The complexes bind to calf-thymus (CT) DNA mainly by intercalation, as concluded by the viscosity measurements and present relatively high DNA-binding constants. The complexes exhibit significant ability to displace ethidium bromide (EB) from the EB-DNA complex, thus indirectly proving the intercalation as the most possible binding mode to CT DNA.

Effect of light transition metal complexes of methanesulfonic acid hydrazide on the viability of yeast Saccharomyces cerevisiae.

The effect of methanesulfonic acid hydrazide (MSH) and its complexes [M(MSH)4Cl2] (M = Mn, Fe, Co, Ni) and [Zn(MSH)2Cl2] on culture growth suppression and viability (Colony Forming Units) of Saccharomyces cerevisiae has been studied. The highest culture growth suppression was exhibited by [Co(MSH)4Cl2], whereas the most cytotoxic appeared [Mn(MSH)4Cl2]. The changes in cell morphology were also traced by means of FACS analysis.

Synthesis, characterization, thermal and DNA-binding properties of new zinc complexes with 2-hydroxyphenones.

The neutral mononuclear zinc complexes with 2-hydroxyphenones (ketoH) having the formula [Zn(keto)2(H2O)2] and [Zn(keto)2(enR)], where enR stands for a N,N'-donor heterocyclic ligand such as 2,2'-bipyridine (bipy), 1,10-phenanthroline (phen) or 2,2'-dipyridylamine (dpamH), have been synthesized and characterized by IR, UV and (1)H NMR spectroscopies. The 2-hydroxyphenones are chelated to the metal ion through the phenolate and carbonyl oxygen atoms. The crystal structures of [bis(2-hydroxy-4-methoxy-benzophenone)(2,2'-bipyridine)zinc(II)] dimethanol solvate and [bis(2-hydroxy-benzophenone)(2,2'-bipyridine)zinc(II)] dimethanol solvate have been determined by X-ray crystallography. The thermal stability of the zinc complexes has been investigated by simultaneous TG/DTG-DTA technique. The ability of the complexes to bind to calf-thymus DNA (CT DNA) has been studied by UV-absorption and fluorescence emission spectroscopy as well as viscosity measurements. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA and the corresponding binding constants to DNA have been calculated and evaluated. The complexes most probably bind to CT DNA via intercalation as concluded by studying the viscosity of a DNA solution in the presence of the complexes. Competitive studies with ethidium bromide (EB) have shown that the reported complexes can displace the DNA-bound EB, suggesting strong competition with EB for the intercalation site.

Zinc complexes of salicylaldehydes: synthesis, characterization and DNA-binding properties.

The neutral mononuclear zinc complexes with substituted salicylaldehydes, in the absence or presence of a nitrogen donor heterocyclic ligand 2,2'-bipyridine or 1,10-phenanthroline or 2,2'-dipyridylamine, have been synthesized and characterized by IR, UV and NMR spectroscopies. The experimental data suggest that salicylaldehyde is on deprotonated mode acting as a bidentate ligand coordinated to the metal ion through the phenolato and one aldehydo oxygen atoms. The crystal structures of bis(5-nitro-salicyladehydato)(2,2'-dipyridylamine)zinc(II), bis(5-chloro-salicylaldehydato)(2,2'-bipyridine)zinc(II) monohydrate and bis(5-bromo-salicyladehydato)bis(methanol)zinc(II) have been determined with X-ray crystallography. The ability of the complexes to bind to calf-thymus DNA (CT DNA) has been studied by UV and fluorescence spectroscopy and viscosity measurements. UV studies of the interaction of the complexes with DNA have shown that they can bind to CT DNA. The calculated binding constants of the complexes to DNA reveal tight binding to DNA. The complexes can probably bind to CT DNA via intercalation as concluded by studying the viscosity of a DNA solution in the presence of the complexes. Competitive studies with ethidium bromide (EB) have shown that the complexes can displace the DNA-bound EB suggesting strong competition with EB for the intercalation site of DNA.

Effect of cobalt(II) complexes with dipyridylamine and salicylaldehydes on cultured tumor and non-tumor cells: synthesis, crystal structure investigations and biological activity.

The synthesis of eight mixed-ligand cobalt(II) complexes with 2,2'-dipyridylamine (dpamH) and substituted salicylaldehydes (X-saloH) was undertaken in an effort to discover new compounds with anticancer activity. The complexes with the general formula [Co(dpamH)(2)(X-salo)]Y, (Y=Br or Cl) were characterized by elemental analyses, FT-IR and UV-visible spectroscopy, magnetic and conductivity measurements. The structures of two of them [Co(dpamH)(2)(5-CH(3)-salo)]Br and [Co(dpamH)(2)(3-OCH(3)-salo)]Cl, as well as of the precursors [Co(dpamH)(3)]Br(2) and [Co(dpamH)(2)Cl(H(2)O)]Cl, were determined by X-ray crystallography revealing octahedral coordination of cobalt(II) and mononuclear complexes. The complexes were thermally stable up to 200 °C in nitrogen atmosphere, studied by simultaneous TG/DTG-DTA technique. The two precursor Co compounds, as well as four of the title compounds, were evaluated for their efficacy as anticancer agents against different cancer and normal human cell lines. The in vitro chemosensitivity of various human cell lines to these Co complexes was evaluated by measuring cell growth inhibition by employing the SRB colorimetric assay. A series of experiments showed a dose-dependent cytotoxic activity of the complexes against all cell lines used. These findings represent a prompting to search for possible interaction of these complexes with other cellular elements of fundamental importance in cell proliferation.

(Carbonato-κO,O')bis-(di-2-pyridyl-amine-κN,N')cobalt(III) bromide.

In the title compound, [Co(CO(3))(C(10)H(9)N(3))(2)]Br, a distorted octa-hedral coordination of the Co(III) atom is completed by four N atoms of the two chelating di-2-pyridyl-amine ligands and two O atoms of the chelating carbonate anion. The di-2-pyridyl-amine ligands are nonplanar and the dihedral angles between the 2-pyridyl groups are 29.11 (9) and 37.15 (12)°. The coordination cation, which has approximate C(2) symmetry, is connected to the bromide ion via an N-H⋯Br(-) hydrogen bond. The ionic pair thus formed is further assembled into a dimer via N-H⋯O inter-actions about an inversion centre. A set of weaker C-H⋯O and C-H⋯Br(-) inter-actions connect the dimers into a three-dimensional network.