Search results for "Metal ions in aqueous solution"

Increasing the nuclearity and spin ground state in a new family of ferromagnetically-coupled {Ni10} disk-like complexes bearing exclusively end-on br…

2018

The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2− ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral.

Influence of metal ions on thermal aggregation of bovine serum albumin: aggregation kinetics and structural changes

2009

Metal ions are implicated in protein aggregation processes of several neurodegenerative pathologies. In this work the effects of Cu(II) and Zn(II) ions on heat-induced structural modifications of bovine serum albumin (BSA) were studied, with the aim of delineating the role of these ions in the early stages of proteins aggregation kinetics. A joint application of different techniques was used. The aggregate growth was followed by dynamic light scattering measurements, whereas the conformational changes occurring in the protein structure were monitored by Raman and IR spectroscopy. Both in absence and in presence of metal ions, heating treatment gave rise to b-structures to the detriment of a…

Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water.

2010

Abstract Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions – Mn2+, Cu2+, Zn2+ and Cd2+ – were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30 min, with 90-95% of metal ions sorbed in first 10 min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30 min of exposition to contaminated water, the concentration of heavy meta…

Metal speciation in biological fluids — a review

1996

The literature on the speciation of metal ions in biological fluids is comprehensively reviewed. Critical examination on this subject reveals that major work has been done in blood and urine. Speciation in materials like milk has not yet been widely studied. On the other hand, only few references could be found on sweat, saliva, cell lysate, cerebrospinal, seminal, tear and bronchoalveolar fluids. The topics studied for these fluids were mainly the speciation of arsenic, mercury, aluminium and selenium. Work on the speciation of other elements like zinc, chromium, cadmium, lead, copper, iron etc. have also been carried out in such matrices. The present literature survey includes also a crit…

Desferrioxamine as an appropriate chelator for 90Nb: Comparison of its complexation properties for M-Df-Octreotide (M=Nb, Fe, Ga, Zr)

2014

The niobium-90 radioisotope ((90)Nb) holds considerable promise for use in immuno-PET, due to its decay parameters (t½ = 14.6h, positron yield=53%, Eß(+)(mean) = 0.35 MeV and Eß(+)(max) = 1.5 MeV). In particular, (90)Nb appears well suited to detect in vivo the pharmacokinetics of large targeting vectors (50-150 kDa). In order to be useful for immuno-PET chelators are required to both stabilize the radionuclide in terms of coordination chemistry and to facilitate the covalent attachment to the targeting vector. Different chelators were evaluated for this purpose in terms of radiolabelling efficiency and stability of the radiolabelled Nb(V) complex and in order to determine the most suitable…

Reversible coordination of dioxygen by tripodal tetraamine copper complexes incorporated in a porous silica framework.

2010

The present study reports the synthesis and rational design of porous structured materials by using a templating method. A tetraethoxysilylated tripodal tetraamine (TREN) was covalently incorporated in a silica framework with a double imprint: A surfactant template and a metal ion imprint. The presence of a cationic surfactant (CTAB) endowed the material with a high porosity, and the tripodal or square-pyramidal topology of the ligand was preserved thanks to the use of the silylated Cu(II) complex. After removal of the surfactant and de-metalation, the incorporated tetraamine was quantitatively complexed by CuCl(2) and the material has shown after thermal activation that a reversible bindin…

Ditopic Aza-Scorpiand Ligands Interact Selectively with ds-RNA and Modulate the Interaction upon Formation of Zn2+ Complexes

2021

Nucleic acids are essential biomolecules in living systems and represent one of the main targets of chemists, biophysics, biologists, and nanotechnologists. New small molecules are continuously developed to target the duplex (ds) structure of DNA and, most recently, RNA to be used as therapeutics and/or biological tools. Stimuli-triggered systems can promote and hamper the interaction to biomolecules through external stimuli such as light and metal coordination. In this work, we report on the interaction with ds-DNA and ds-RNA of two aza-macrocycles able to coordinate Zn2+ metal ions and form binuclear complexes. The interaction of the aza-macrocycles and the Zn2+ metal complexes with duple…

Studies on mechanism and physico-chemical parameters at the origin of the cement setting II. Physico-chemical parameters determining the coagulation …

1996

The physico-chemical parameters determining the coagulation of cements grains previously identified as the first fundamental process of cement setting have been investigated in diluted suspensions using an adapted granulometric method. The analysis of the influence of the ionic concentration in solution on the coagulation reveals that calcium concentration is the parameter which determines the particle interactions. There exists a minimum critical concentration of calcium ions in solution which is required to occur the coagulation of cement particles and a dispersive effect appears for very high concentrations. The results are discussed in relation with DLVO theory and specific interactions.

Book Review: Ions in Solution: Basic Principles of Chemical Interactions. By J. Burgess

1989

Transportation of complexing agents released by pulp and paper industry: A Finnish lake case

1996

Complexing agents (EDTA, DTPA) are used to bind metal ions in pulp and paper industry. Their role will increase significantly when the total chlorine free (TCF) processes will be applied to a larger extent. EDTA and DTPA were analysed in the waters from the southern part of the Lake Saimaa (SE Finland) influenced by the effluents of three pulp and paper mills. The samples were collected at different distances from the points of emission. The results of analyses suggest that EDTA can persist in lake water and is able to propagate for considerable distances, while DTPA can be detected only in the near surroundings of the site of release. Some EDTA was found even in the sampling points that we…