Binary and ternary chromium(III) complexes with cellular reductants and DNA components isolated from redox type systems. Part 1. Chromium(VI)–cysteine–adenine (adenosine,ATP)

The reduction of CrO₃ with an excess of L-cysteine and its interaction with DNA fragments (adenine, adenosine) and ATP nucleotide was studied by analysis of the isolated solid products. The precipitates were characterised by elemental analyses, FAB mass spectral data, spectroscopic methods (u.v.–vis., f.i.r., i.r.) and magnetic measurements. The Cr^III complexes obtained appear to be various Cr^III cysteinate and adenine or ATP (but not adenosine) ternary species of the addition type bound through the hydrogen bonding network.     

Binary and ternary chromium(III) complexes with cellular reductants and DNA components isolated from redox type systems. Part 2. Chromium(VI)—glutathione—adenine (adenosine,ATP)

The reduction of CrO₃ with an excess of glutathione and its interaction with DNA fragments (adenine, adenosine) and the ATP nucleotide was studied by analysis of the isolated solid products. The precipitates were characterised by elemental analyses, FAB-mass spectral data, spectroscopic methods (u.v.–vis., i.r., f.i.r.) and magnetic measurements. The Cr^III complexes obtained from ternary systems appeared to be [Cr^III—glutathione] and [Cr^III—glutathione—adenine (adenosine, ATP)] species. The structure of the complexes has been proposed assuming hydrogen bonding between the Cr^III GSH complex and the DNA fragment.     

Interaction of Carcinogenic Chromium(VI) Oxide,CrO3, with Main Nonenzymatic Cellular Reductants at Physiological Conditions. Electronic Spectra and Magnetic Studies

The interaction of CrO₃ with ascorbic acid, glutathione and cysteine at physiological conditions (pH=7.4, t=37°C) was investigated using spectral (diffuse reflectance spectra) and magnetic methods. The obtained powders appeared to be Cr(III) complexes of the [Cr(A, B)(H₂O)_x]^n- type, where A, B are organic ligands (A-ascorbic acid, B-glutathione or cysteine). The spectral resolution of the bands enhanced with a digital filter method revealed the lowering symmetry effect in the chromium(III) coordination sphere. The comparison of the results obtained for K₂CrO₄ with these studied in the present paper was made.     

Review: an overview of recent developments in coordination chemistry of polypyrazolylmethylamines. Complexes with N-scorpionate ligands created in situ from pyrazole derivatives and zerovalent metals

This paper reviews the coordination chemistry of polypyrazolylmethylamines as tripodal tetradentate (L^S = N,N,N-tris(3,5-dimethylpyrazol-1-ylmethyl)amine) and dipodal tridentate (L^D = N,N,-bis(3,5-dimethylpyrazol-1-ylmethyl)amine) ligands. References to the methods for the synthesis of both the ligands alone and their transition metal complexes are given with emphasis placed on the structural features of the latter. Special attention was paid to the one-pot synthesis, which is a new method for isolation of various metal complexes with N,N-bis- and N,N,N-trispyrazolylmethylamines and co-ligands, such as urotropine and 3,5-dimethylpyrazole. The complexes in question were created in situ from 1-hydroxymethyl-3,5-dimethylpyrazole (L⁰) and zerovalent metals.     

Synthesis, X-ray structure, and spectroscopic investigation of new Co(II)/Cd(II) complexes formed via the reaction of 1-hydroxymethyl-3,5-dimethylpyrazole and Co0, CdCl2, NH4I

The novel complex [Co(L)Cl]₂[CdI₄] obtained in situ from the redox system (Co⁰, CdCl₂, NH₄I, 1-hydroxymethyl-3,5-dimethylpyrazole) was characterized by X-ray diffraction IR, UV–VIS as well as magnetic and thermal investigations. The ligand, tris(1-(3,5-dimethylpyrazolylmethyl)amine (L) was synthesized in situ as a product of condensation 1-hydroxymethyl-3,5-dimethylpyrazole and ammonia molecule formed during redox process. The crystal structure of 1 includes in the unit cell two chemically identical but symmetry-independent cations: [Co(1)(L)Cl]⁺ and [Co(2)(L)Cl]⁺. Each of the [Co(L)Cl]⁺ complex ions has C₃ point group symmetry, but the point group symmetry of the trigonal bipyramidal coordination spheres of [CoN₃N′Cl] and tetrahedral sphere of [CdI₄] has C_3v point group symmetry.     

Binary and ternary chromium(III) complexes with cellular reductants and DNA components isolated from redox type systems. Part 3. Chromium(VI) – <Emphasis Type="SmallCaps">L</Emphasis>-ascorbic acid – adenine (adenosine,ATP)

The reduction of CrO3 with an excess of L-ascorbic acid and its interaction with DNA fragments (adenine, adenosine) and the ATP nucleotide was studied by the analysis of the isolated solid products. The precipitates were characterised by elemental analyses, FAB-mass spectral data, spectroscopic methods (u.v.–vis., i.r) and magnetic measurements. The Cr^III complexes obtained from ternary systems appeared to be [Cr^III–L-ascorbic acid] and [Cr^III–L-ascorbic acid–adenine (adenosine, ATP)] species. The structure of ternary complexes has been proposed assuming hydrogen bond formation between the [Cr^III–ascorbic acid] complex and the DNA components. The effect of main cellular reductants: cysteine, glutathione and L-ascorbic acid on the composition and structure of isolated products has been discussed.     

Thermal and structural properties of coordination compounds of 2-mercapto-1-methylimidazole with palladium(II) and platinum(II)

Complexes of 2-mercapto-1-methylimidazole (TMZ) with Pd^II and Pt^II of the general formula M(TMZ)_nX₂ (whereM=Pd, Pt andX=Cl, Br, I or SO₄ andn=2 or 4) were obtained. The thermal stabilities of the compounds were estimated by derivatographic measurements and lattice constants were estimated from their X-ray powder diffraction patterns.     

Are Biogenic and Pyrogenic Mesoporous SiO2 Nanoparticles Safe for Normal Cells?

Silicon dioxide, in the form of nanoparticles, possesses unique physicochemical properties (size, shape, and a large surface to volume ratio). Therefore, it is one of the most promising materials used in biomedicine. In this paper, we compare the biological effects of both mesoporous silica nanoparticles extracted from Urtica dioica L. and pyrogenic material. Both SEM and TEM investigations confirmed the size range of tested nanoparticles was between 6 and 20 nanometers and their amorphous structure. The cytotoxic activity of the compounds and intracellular ROS were determined in relation to cells HMEC-1 and erythrocytes. The cytotoxic effects of SiO₂ NPs were determined after exposure to different concentrations and three periods of incubation. The same effects for endothelial cells were tested under the same range of concentrations but after 2 and 24 h of exposure to erythrocytes. The cell viability was measured using spectrophotometric and fluorimetric assays, and the impact of the nanoparticles on the level of intracellular ROS. The obtained results indicated that bioSiO₂ NPs, present higher toxicity than pyrogenic NPs and have a higher influence on ROS production. Mesoporous silica nanoparticles show good hemocompatibility but after a 24 h incubation of erythrocytes with silica, the increase in hemolysis process, the decrease in osmotic resistance of red blood cells, and shape of erythrocytes changed were observed.     

Interaction of hydantoins with transition metal ions: synthesis,structural, spectroscopic,thermal and magnetic properties of [M(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>(phenytoinate)<Subscript>2</Subscript>] M = Ni(II), Co(II)

Complexes of Ni(II) and Co(II) of the formulae [Ni(H₂O)₄(pht)₂] (1) and [Co(H₂O)₄(pht)₂]·1,5NH₃·H₂O (2) (where pht = phenotoinate anion) were obtained and characterized physicochemically. [Ni(H₂O)₄(pht)₂] (1) crystallizes in a monoclinic space group P2₁/c; a = 11.7358(8), b = 11,1250(8), 11.4182(7) Å; β = 97.076(5)°; V = 1479.41 Å³; Z = 2. The environment around the nickel and cobalt ions can be described as a distorted octahedron. The metal ion was found to bind to four water molecules and two nitrogen atoms derived from two anions of the monodentate phenytoinate. Four intramolecular hydrogen bonds designated as S(6) graph set are found in one [Ni(H₂O)₄(pht)₂] (1) molecule. Two chain HB patterns, constructed by the [Ni(H₂O)₄(pht)₂] molecules extending along the c and b axes, respectively, have been observed. The cobalt complex precipitates with the additional solvent molecules: one and a half of ammonia and one water. The results document the preferential binding of hydantoins to the metal ions through N(3) atom.