Search results for "Chela"
showing 10 items of 415 documents
Synthesis and Complexation of the Metalloligand {(η5-C5H5)[η5-C5Me3-1,2-(PPh2)2]TiCl2} (TiPHOS): The First Example of a 1,2-Bis(diphenylphosphanyl)ti…
2001
The reaction of lithium 1,2-bis(diphenylphosphanyl)trimethylcyclopentadienide (1) with CpTiCl3 leads to the formation of the titanocene diphosphane {(η5-C5H5)[η5-C5Me3-1,2-(PPh2)2]TiCl2} (TiPHOS, 2). This metalloligand reacts readily with (NBD)Cr(CO)4 and W(CO)5(THF) to give, in both cases, the bimetallic chelate complexes (TiPHOS)Cr(CO)4 (3) and (TiPHOS)W(CO)4 (4). The structure of 4 has been determined by X-ray diffraction. The synthesis of a new early-late heterobimetallic complex (TiPHOS)Rh(CO)Cl (5) is reported.
Sequestering ability of some chelating agents towards methylmercury(II).
2013
A study on the interactions between CH3Hg+ and some S, N and O donor ligands (2-mercaptopropanoic acid (thiolactic acid (H2 TLA)), 3-mercaptopropanoic acid (H2 MPA), 2-mercaptosuccinic acid (thiomalic acid (H3 TMA)), d,l-penicillamine (H2 PSH), l-cysteine (H2 CYS), glutathione (H3 GSH), N,N′-bis(3-aminopropyl)-1-4-diaminobutane (spermine (SPER)), 1,2,3,4,5,6-benzenehexacarboxylic acid (mellitic acid (H6 MLT)) and ethylenediaminetetraacetic acid (H4 EDTA)) is reported. The speciation models in aqueous solution and the possible structures of the complexes formed are discussed on the basis of potentiometric, calorimetric, UV spectrophotometric and electrospray mass spectrometric results. For t…
Hemin-coupled iron(III)-hydroxide nanoparticles show increased uptake in Caco-2 cells
2011
Abstract Objectives The absorption of commonly used ferrous iron salts from intestinal segments at neutral to slightly alkaline pH is low, mainly because soluble ferrous iron is easily oxidized to poorly soluble ferric iron and ferrous iron but not ferric iron is carried by the divalent metal transporter DMT-1. Moreover, ferrous iron frequently causes gastrointestinal side effects. In iron(III)-hydroxide nanoparticles hundreds of ferric iron atoms are safely packed in nanoscaled cores surrounded by a solubilising carbohydrate shell, yet bioavailability from such particles is insufficient when compared with ferrous salts. To increase their intestinal uptake iron(III)-hydroxide nanoparticles …
Synthesis and characterization of some arsenic, antimony and bismuth complexes of 2-mercaptoaniline
1983
Abstract The complexes of arsenic, antimony and bismuth as well as phenylantimony and phenylbismuth with monoanionic 2-mercaptoaniline are reported. IR spectra are consistent with chelating behaviour of the ligand but only a weak nitrogen to metal bonding interaction is advanced. The mass spectra fragmentation pattern is also presented. It can be interpreted with the loss of successive ligand units and, as a general feature, the abundance of a given ion decreases as the mass of the metal increases. Species with one or two protons less give more intense peaks possibly corresponding to ions containing the dianionic form of the ligand.
Dinitrosyl-iron triggers apoptosis in Jurkat cells despite overexpression of Bcl-2
2004
Cells expressing the cytokine-inducible NO synthase are known to trigger apoptosis in neighboring cells. Paramagnetic dinitrosyl nonheme iron complexes (DNIC) were found in tumor tissue about 40 years ago; however, the role of these NO(+)-bearing species is not completely understood. In the human Jurkat leukemia cell line, the application of the model complex DNIC-thiosulfate (50-200 microM) induced apoptosis (defined by phosphatidylserine externalization) in a concentration- and time-dependent manner. In Jurkat cells, the pan-caspase inhibitor, zVADfmk (50 microM), and/or stable transfection of antiapoptotic protein, Bcl-2, was unable to afford protection against DNIC-induced apoptosis. Th…
Calretinin/PSA-NCAM immunoreactive granule cells after hippocampal damage produced by kainic acid and DEDTC treatment in mouse.
2003
There is a dramatic increase in the number of lightly immunoreactive calretinin cells in the granular layer of the dentate gyrus of the mouse hippocampus 1 day after excitotoxic injury using kainic acid combined with the zinc chelator diethyldithiocarbamate. At 7 days after treatment, these cells are strongly immunoreactive for calretinin and for the polysialated form of the glycoprotein neural cell adhesion molecule (PSA-NCAM). The reexpression of calretinin and PSA-NCAM after treatment corresponds well with the loss of input from the damaged hilar mossy cells. These cells could be considered immature granule cells since they are immunoreactive to markers for immature cells such as PSA-NCA…
Effect of EDTA on divalent metal adsorption onto grape stalk and exhausted coffee wastes
2007
In the present work, two industrial vegetable wastes, grape stalk, coming from a wine producer, and exhausted coffee, coming from a soluble coffee manufacturer, have been investigated for the removal of Cu(II) and Ni(II) from aqueous solutions in presence and in absence of the strongly complexing agent EDTA. Effects of pH and metal-EDTA molar ratio, kinetics as a function of sorbent concentration, and sorption equilibrium for both metals onto both sorbents were evaluated in batch experiments. Metal uptake was dependent of pH, reaching a maximum from pH around 5.5. EDTA was found to dramatically reduce metal adsorption, reaching total uptake inhibition for both metals onto both sorbents at e…
Data from: Plant – herbivorous beetle networks: molecular characterization of trophic ecology within a threatened steppic environment
2015
DNA barcoding facilitates many evolutionary and ecological studies, including the examination of the dietary diversity of herbivores. In this study, we present a survey of ecological associations between herbivorous beetles and host plants from seriously threatened European steppic grasslands. We determined host plants for the majority (65%) of steppic leaf beetles (55 species) and weevils (59) known from central Europe using two barcodes (trnL and rbcL) and two sequencing strategies (Sanger for mono/oligophagous species and Illumina for polyphagous taxa). To better understand the ecological associations between steppic beetles and their host plants, we tested the hypothesis that leaf beetl…
Titanium Complexes of Chelating Bis(phenolato) Ligands with Long Titanium−Sulfur Bonds. A Novel Type of Ancillary Ligand for Olefin Polymerization Ca…
1996
The sulfide-linked bis(phenol) tbmpH2 (tbmp = 2,2‘-thiobis(6-tert-butyl-4-methylphenolato)) gives a series of titanium complexes of the formula [Ti(tbmp)X2]2 or [Ti(tbmp)(L)X2] (L = two-electron ligand, X = one-electron ligand). The molecular structures of [Ti(tbmp)(OiPr)2]2 and of [Ti(tbmp){C6H4(CH2NMe2)-2}Cl] were determined by single-crystal X-ray structural analyses. An unusually long titanium−sulfur bond of ∼270 pm is observed in both complexes which contain a six-coordinate titanium center. Variable-temperature NMR spectroscopy shows a fluxional coordination of the chelating aryl group in [Ti(tbmp){C6H4(CH2NMe2)-2}Cl].
Heterocyclic systems containing antimony (III) -VIII . Hypervalency by intramolecular 1,5-chelation Sb · · · N in rings RSb [ (CH2) 3] 2NR′ (NR′ = NM…
1998
Abstract Eleven antimony compounds RSb [ (CH2) 3] 2 NR′ and eight germanium compounds R2Ge [ (CH2) 3] 2 NR′ (some combinations of R = Cl, I, NCS, OSiPh3, Ph, and NR′ = NMe, NBz, NBui) have been synthesized by diGrignard reactions and subsequent treatment with AgSCN, Ph3SiONa or PhLi. The compounds were compared to 14 Sn, 1 As, 5 Sb and 4 Bi analogues taken from the literature. Evidence is provided for 1,5-chelation Sb · · · N via crystal structure determinations (5+1 (lit) Sb compounds) , 13C- and 29Si-NMR chemical shifts, 12;Sb and 12;I Mossbauer data (11 and 3 Sb compounds, respectively) , cyclic voltammetry (9 Sb compounds) and semi-empirical MO calculations on the Extended Huckel level …