Search results for "Metal Ion"

Aza–oxa macrocyclic ligands functionalised with naphthylmethyl fluorescent groups

2000

Abstract Compounds L 1 and L 2 were obtained by reaction of 2-(bromomethyl)naphthalene with 1,4,10-trioxa-7,13-diazacyclopentadecane and 1,4,7-trioxa-10-azacyclododecane, respectively. These receptors contain aza–oxa crowns attached covalently to fluorescent groups. The protonation and coordination behaviour of L 1 and L 2 against metal ions has been studied in dioxane:water (70:30 v/v, 25°C, 0.1 M potassium nitrate) using potentiometric methods. All metal ions studied form complexes with L 1 and L 2 with the logarithm of the formation constants L+M 2+ =[M(L)] 2+ in the sequence Cd 2+ ≅Pb 2+ , Zn 2+ 2+ for L 1 and Zn 2+ 2+ 2+ 2+ 2+ for L 2 . The fluorescent behaviour of L 1 and L 2 was stud…

The role of metal ions in the thermal aggregation of Bovine Serum Albumin

2009

Kinetic evidence for the solubilization of pyridine-2-azo-p-dimethylaniline in alkanediyl-α,ω-bis(dimethylcetylammonium nitrate) surfactants. Role of…

2004

The incorporation of the bidentate ligand pyridine-2-azo-p-dimethylaniline (PADA) into micellar aggregates of the dimeric cationic surfactants propanediyl-, hexanediyl- and dodecanediyl-alpha,omega-bis(dimethylcetylammonium nitrate) (16-3-16,2NO(3)(-), 16-6-16,2NO(3)(-) and 16-12-16,2NO(3)(-), respectively) has been studied at 25 degreesC by examining the kinetics of the complexation reaction of the Ni(II) ion with this ligand. For comparison, cetyltrimethylammonium nitrate ( CTAN), which can be considered as the "monomeric'' surfactant of 16-3-16,2NO(3)(-), has also been used. The kinetic data have shown that, for 16-3-16,2NO(3)(-) and CTAN, at a surfactant concentration below the critical…

New sulfonamide complexes with essential metal ions [Cu (II), Co (II), Ni (II) and Zn (II)]. Effect of the geometry and the metal ion on DNA binding …

2019

Abstract Mixed divalent Cu, Co, Ni and Zn complexes containing the new sulfonamide ligand N–(2–(pyridin–2–yl)ethyl)quinoline–8–sulfonamide (HQSEP) were prepared and characterized by physico-chemical techniques. The tetracoordinate [Cu(QSEP)X] [X = Br (1), Cl (2)] compounds present a seesaw geometry (τ4 = 0.56 (1) and 0.50 (2)). The Cu(II) in the [Cu(QSEP)(NO3)(MeOH)] (3) complex is five coordinate with a slightly distorted SP geometry (τ = 0.11). The [M(QSEP)(benz)] [M = Cu(II) (4), Ni(II) (5), Co(II) (6) and Zn(II) (7); benz = benzoate] compounds are configurationally isotypic. The coordination geometries of the M(II) ions can be best described as distorted SP (τ = 0.29, 0.15, 0.34 and 0.1…

Development of a biosensor for copper detection in aqueous solutions using an Anemonia sulcata recombinant GFP.

2014

Fluorescent proteins from marine organisms represent potential candidates for biosensor development. In this paper, we described the isolation of a native green fluorescent protein from Anemonia sulcata and the cloning and purification of its equivalent as a recombinant protein in Escherichia coli. Furthermore, the spectroscopic behaviours of the native and recombinant GFPs were investigated as a function of Cu2+, Cd2+, Pb 2+ and Ni2+ concentration. Our results suggest the high selectivity of both proteins at copper than the other metals and, for the recombinant protein, a great sensitivity at a very low concentration (0.1-1 μM). Moreover, starting from these data, using the combination of …

X-ray absorption spectroscopic study of trivalent and tetravalent actinides in solution at varying pH values

2009

Abstract We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH2OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH3NaO3S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms be…

Subcomponent Self-Assembly A Quick Way to New Metallogels

2013

Subcomponent self-assembly, introduced by the Nitschke group,[1] is a process which allow complex structures to be generated from simple building blocks (generally aldehydes and amines). In this bottom-up approach, the building blocks spontaneously self-assemble around templates (usually metal ions) leading to a simultaneous covalent (C=N) and dative (N– metal) bonds formation. The method has been successfully used to construct well-defined metal-organic macrocycles, helicates, catenanes, rotaxanes, grids,[2] and cages.[3] Our field of interest lies not in building-up of defined structures but in designing gelator molecules for a formation of supramolecular gels as functional nanomaterials.…

Polynuclear copper(II) complexes with hexadentate Schiff base directed by the counter ion. Syntheses, crystal structures and magnetic properties

2018

Abstract Four new complexes, [Cu 9 L 6 ( µ 3 -ClO 4 ) 2 ](ClO 4 ) 4 ·4CHCl 3 1 , [Cu 3 L 2 (H 2 O) 2 ](ClO 4 ) 2 ·3H 2 O 2 , [Cu 6 L 4 (N 3 ) 2 ](ClO 4 ) 2 3 and [Cu 2 L(CH 3 COO) 2 ] 4 , where H 2 L stands for the Schiff base N , N ′-bis[(2-hydroxybenzilideneamino)-propyl]-piperazine, were obtained and structurally characterized. Compounds 1 , 2 and 3 contain the Cu 3 L 2 2+ entities in which L 2− acts in an unsymmetrical mode with N 3 O donor set wrapped around marginal copper(II) and with the remained NO sets bound to the central copper ion. The marginal copper(II) ions are in distorted square pyramidal environment, whereas that of the central one is square planar. In 1 , the peripheral …

A Series of MIICuII3 Stars (M = Mn, Ni, Cu, Zn) Exhibiting Unusual Magnetic Properties

2014

The work in this report describes the syntheses, electrospray ionization mass spectromtery, structures, and experimental and density functional theoretical (DFT) magnetic properties of four tetrametallic stars of composition [M(II)(Cu(II)L)3](ClO4)2 (1, M = Mn; 2, M = Ni; 3, M = Cu; 4, M = Zn) derived from a single-compartment Schiff base ligand, N,N'-bis(salicylidene)-1,4-butanediamine (H2L), which is the [2 + 1] condensation product of salicylaldehyde and 1,4-diaminobutane. The central metal ion (Mn(II), Ni(II), Cu(II), or Zn(II)) is linked with two μ2-phenoxo bridges of each of the three [Cu(II)L] moieties, and thus the central metal ion is encapsulated in between three [Cu(II)L] units. …

Sequestering ability of landfill leachate towards toxic metal ions

2017

The great part of municipal solid wastes is worldwide stored in sanitary landfills. The interaction of organic and inorganic wastes with rainwater produces in the landfill a leachate of extremely variable composition. It depends on several variables such as the type of wastes, the age of landfill, the pH, the redox potential, etc [1-2]. Four are the recognized categories of pollutants in landfill leachate: inorganic macrocomponents, dissolved organic matter (DOM), heavy metals and xenobiotic organic compounds [3]. In particular, heavy metals (arsenic, cadmium, copper, lead, mercury, etc.) are usually present at concentration of few ppb and up to some ppm. A variable but consistent fraction …