New Ni(II)-sulfonamide complexes: Synthesis, structural characterization and antibacterial properties. X-ray diffraction of [Ni(sulfisoxazole)(2)(H2O)(4)] center dot 2H(2)O and [Ni(sulfapyridine)(2)]

The synthesis, structural characterization, voltammetric experiments and antibacterial activity of [Ni(sulfisoxazole)(2)(H2O)(4)] center dot 2H(2)O and [Ni(sulfapyridine)(2)] were studied and compared with similar previously reported copper complexes. [Ni(sulfisoxazole)(2)(H2O)(4)] center dot 2H(2)O crystallized in a monoclinic system, space group C2/c where the nickel ion was in a slightly distorted octahedral environment, coordinated with two sulfisoxazole molecules through the heterocyclic nitrogen and four water molecules. [Ni(sulfapyridine)(2)] crystallized in a orthorhombic crystal system, space group Pnab. The nickel ion was in a distorted octahedral environment, coordinated by two aryl amine N from two sulfonamides acting as monodentate ligands and four N atoms (two sulfonamidic N and two heterocyclic N) from two different sulfonamide molecules acting as bidentate ligands. Differential pulse voltammograms were recorded showing irreversible peaks at 1040 and 1070 mV, respectively, attributed to Ni(II)/Ni(III) process. [Ni(sulfisoxazole)(2)(H2O)(4)] center dot 2H(2)O and [Ni(sulfapyridine)(2)] presented different antibacterial behavior against Staphylococcus aureus and Escherichia coli from the similar copper complexes and they were inactive against Mycobacterium tuberculosis. (c) 2007 Elsevier Inc. All rights reserved.

Effects of Cobalt Chloride in Junctional Epithelium and Reduced Enamel Epithelium of the Rat Maxillary First Molar

Cobalt is one of the main components of cast metal alloys broadly used in dentistry. It is the constituent of 45 to 70% of numerous prosthetic works. There are evidences that metal elements cause systemic and local toxicity. The purpose of the present study was to evaluate the effects of cobalt on the junctional epithelium and reduced enamel epithelium of the first superior molar in rats, during lactation. To do this, 1-day old rats were used, whose mothers received 300mg of cobalt chloride per liter of distilled water in the drinker, during lactation. After 21 days, the rat pups were killed with an anesthetic overdose. The heads were separated, fixed in ""alfac"", decalcified and embedded in paraffin. Frontal sections stained with hematoxylin and eosin were employed. Karyometric methods allowed to estimate the following parameters: biggest, smallest and mean diameters, D/d ratio, perimeter, area, volume, volume/area ratio, eccentricity, form coefficient and contour index. Stereologic methods allow to evaluate: cytoplasm/nucleus ratio, cell and cytoplasm volume, cell number density, external surface/basal membrane ratio, thickness of the epithelial layers and surface density. All the collected data were subjected to statistic analysis by the non-parametric Wilcoxon-Mann-Whitney test. The nuclei of the studied tissues showed smaller values after karyometry for: diameters; perimeter, area, volume and volume/area ratio. Stereologically, it was observed, in the junctional epithelium and in the reduced enamel epithelium, smaller cells with scarce cytoplasm, reflected in the greater number of cells per mm3 of tissue. In this study, cobalt caused epithelial atrophy, indicating a direct action on the junctional and enamel epithelium.

Synthesis, characterization and evaluation of antileishmanial activity of copper(II) with fluorinated alpha-hydroxycarboxylate ligands

In this study, Cu(II) complexes with fluorinated ligands were produced aiming at the development of new, less toxic antileishmanial metallodrugs. Complexes of the general formula CuL(2) (L = lactate, trifluorolactate, 2-hydroxyisobutyrate, trifluoro-2-hydroxyisobutyrate) were synthesized in methanolic medium, purified by crystallization and characterized by elemental analysis and electronic and infrared spectroscopies. In vitro experiments with Leishmania amazonensis promastigotes showed that the trifluorolactate derivative more active than its non-fluorinated counterpart. Our results indicate that fluorinated chelators may be interesting to increase metal toxicity and/or open new paths for metallodrug chemotherapy against leishmaniasis.

On an Electrode Modified by a Supramolecular Ruthenium Mixed Valence (Ru(II)/Ru(III)) Diphosphine-Porphyrin Assembly

Three novel polymetallic ruthenium (III) meso-tetra(4-pyridyl)porphyrins containing peripheral ""RuCl(3)(dppb)"" moieties have been prepared and characterized. The X-ray structure of the tetraruthenated {NiTPyP[RuCl(3)(dppb)](4)} porphyrin complex crystallizes in the triclinic space group FT. This structure is discussed and compared with the crystal data for the mer-[RuCl(3)(dppb)(py)]. The {TPyP[RuCl(3)(dppb)](4)} and {CoTPyP[RuCl(3)(dppb)](4)} porphyrins were used to obtain electrogenerated films on ITO and glass carbon electrode surfaces, respectively. Such tetraruthenated porphyrins form films of a mixed-valence species {TPyP[Ru(dppb)](4)(mu Cl(3))(2)}(2)(4n2+) and {CoTPyP[Ru(dppb)](4)(mu Cl(3))(2)}(2n)(4n2+) on the electrode surface. The modified electrode with {CoTPyP[RuCl(3)(dppb)](4)} is very stable and can be used to detect organic substrates such as catechol.