Search results for "METAL COMPLEXES"
showing 10 items of 51 documents
The solution behavior of dopamine in the presence of mono and divalent cations: A thermodynamic investigation in different experimental conditions
2021
The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop-)] with methylmercury(II) (CH3Hg+), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn2+ we observed the formation of binuclear complexes (M2L2 and M2LOH (charge omitted for simplicity)
Designing binuclear transition metal complexes: a new example of the versatility of N,N′-bis(2-aminobenzyl)-4,13-diaza-18-crown-6
2005
[Abstract] N,N′-Bis(2-aminobenzyl)-4,13-diaza-18-crown-6 (L) is a versatile receptor able to adapt to the coordinative preferences of different metal cation guests. With first-row transition metal ions, L tends to form binuclear complexes but, depending on the nature of the particular metal ion, the structure of the binuclear complex may be very different. Herein we report a study of the structure and magnetic properties of the corresponding nickel(II) and cobalt(II) complexes. The X-ray crystal structure of the nickel complex (1), with formula [Ni2(L)(CH3CN)4](ClO4)4·CH3CN, shows that this compound presents a symmetric coordination environment with L adopting an anti arrangement. Each Ni(I…
Quantitative Analysis of the Interactions of Metal Complexes and Amphiphilic Systems: Calorimetric, Spectroscopic and Theoretical Aspects.
2022
Metals and metal-based compounds have many implications in biological systems. They are involved in cellular functions, employed in the formation of metal-based drugs and present as pollutants in aqueous systems, with toxic effects for living organisms. Amphiphilic molecules also play important roles in the above bio-related fields as models of membranes, nanocarriers for drug delivery and bioremediating agents. Despite the interest in complex systems involving both metal species and surfactant aggregates, there is still insufficient knowledge regarding the quantitative aspects at the basis of their binding interactions, which are crucial for extensive comprehension of their behavior in sol…
Metal complexes of oxadiazole ligands: An overview
2019
Oxadizoles are heterocyclic ring systems that find application in different scientific disciplines, from medicinal chemistry to optoelectronics. Coordination with metals (especially the transition ones) proved to enhance the intrinsic characteristics of these organic ligands and many metal complexes of oxadiazoles showed attractive characteristics for different research fields. In this review, we provide a general overview on different metal complexes and polymers containing oxadiazole moieties, reporting the principal synthetic approaches adopted for their preparation and showing the variety of applications they found in the last 40 years.
The Impact of Humic Substances as Remediation Agents to the Speciation Forms of Metals in Soil
2013
Abstract Humic substances (HS) are the most widespread group of organic substances in natural environment and have high stability. The main terrestrial reserves are found in the form of naturally occurring ore, peat or lignite. The aim of this paper is to study possibilities to use HS as agents for remediation of contaminated with heavy metals soil and impacts of HS of metal speciation forms in it. It has been proved that HS are able to bind to metal ions and change their speciation forms in soils. The ability to form complexes with metal ions depends on the type of soil, type of metal, as well as concentrations of HS in soil. The study was carried out in experimental conditions and analyti…
Phospha-Fischer Carbenes: Synthesis, Structure, Bonding, and Reactions of Pd(0)− and Pt(0)−Phosphenium Complexes
2009
The analogy between cationic group 10 metal−phosphenium complexes and Fischer carbenes has been formalized through structural and reactivity studies and by energy decomposition analysis (EDA) of the M−P bond. The studied compounds were the three-coordinate, 16-electron species [(NHPMes)M(PPh3)2]OTf (M = Pt (1) and Pd (2); [NHPMes]+ is the N-heterocyclic phosphenium (NHP) cation, [tiebar above startPN(2,4,6-Me3-C6H2)CH2CH2tiebar above endN(2,4,6-Me3-C6H2)]+, OTf = trifluoromethanesulfonate); these were made by reaction of [NHPMes]OTf with M(PPh3)4. The metal−phosphenium bond in both compounds was dominated by metal-to-ligand π-donation. This differed from the M−C bonds in the analogous N-het…
Antiproliferative Properties of a Few Auranofin-Related Gold(I) and Silver(I) Complexes in Leukemia Cells and their Interferences with the Ubiquitin …
2020
A group of triethylphosphine gold(I) and silver(I) complexes, structurally related to auranofin, were prepared and investigated as potential anticancer drug candidates. The antiproliferative properties of these metal compounds were assessed against two leukemia cell lines, i.e., CCRF-CEM and its multidrug-resistant counterpart, CEM/ADR5000. Interestingly, potent cytotoxic effects were disclosed for both series of compounds against leukemia cells, with IC50 values generally falling in the low-micromolar range, the gold derivatives being on the whole more effective than the silver analogues. Some initial structure-function relationships were drawn. Subsequently, the ability of the study compo…
Selective G-quadruplex stabilizers: Schiff-base metal complexes with anticancer activity
2014
The affinity of three square-planar nickel(II) (1), copper(II) (2) and zinc(II) (3) Schiff-base complexes for wild-type human telomeric (h-Telo) and protooncogene c-myc G-quadruplex (G4) DNA was investigated by UV-visible absorption spectroscopy and circular dichroism. DNA-binding constants (Kb) were determined by spectrophotometric titrations for both G4-DNA and B-DNA. The results obtained point out that the three metal complexes selectively bind G4-DNA with higher affinity, up to two orders of magnitude, with respect to B-DNA. The nickel(II) complex 1 was found to be the most effective G4-DNA stabilizer and the Kb values decrease in the order 1 > 2 ≈ 3. Innovative computational investigat…
Kinetic and equilibrium study for Pd(II) removal from aqueous solution by sorption onto calcium alginate gel beads
2013
The more and more increasing use of catalytic converters to reduce the dangerous NOx and CO emission in the atmosphere by vehicle traffic produces a corresponding increase of palladium in the environment [1]. Among the so-called “platinum group Elements” (PGE), elemental palladium seems to be the most hazardous one because it can be easily and quickly oxidized to palladium(II) when put in contact with soil. The presence of palladium oxidized form is of great concern owing to its recognized toxicity towards plants, animals and humans. Therefore, as for the classical “heavy metals”, a removal of this element from the environment is needed and a subsequent recovery for its potential re-use is …