Search results for "Complexation"
showing 10 items of 30 documents
Recognition of oxovanadium(V) species and its separation from other metal species through selective complexation by some acyclic ligands
1998
Acyclic molecules possessing –OH (phenoxo and alkoxo type) groups and imine or amine moieties have been developed to sense the specific preference for VO3+ species. These molecules also showed a capability to quantitatively separate oxovanadium(V) species from a reaction mixture containing metal species of V, Mo, U, Fe, and Mn ions in solution. A cascade quantitative separation of VO3+ followed by cis–MoO2+2 followed by trans –UO2+2 species is demonstrated from their mixture. Synthesis and structural details of oxo-species of vanadium molybdenum and uranium are also discussed. Factors influencing the complexation of these molecules towards oxo metal species of V, Mo and U are also addressed.
Specific separation and recovery of phosphate anions by a novel NiFe-LDH/rGO hybrid film based on electroactivity-variable valence
2022
Phosphorus is a non-renewable resource. Supplies are limited and much phosphorus is currently wasted during the production and utilization process, causing concerns about future supplies and widespread environmental problems. To solve these problems, a new type of NiFe-LDH/rGO electrically switched ion-selective (ESIX) film is designed, based on the dominant mechanism of inner-sphere complexation. An ESIX process allows the NiFe-LDH/rGO hybrid film to achieve a controllably selective uptake and release of the phosphate anions. This route involves tuning potential steps to regulate the redox states of the composite film and the variable metal (e.g., Ni, Fe (II)/(III)) in coordination centers…
Synthesis, characterisation and complexation of di- and trifunctional hybrid ferrocenylphosphine ligands.
2020
Organometallic compounds with at least one metal-carbon bond are used in various fields of chemistry: for example, in medical research for anticancer treatments, in catalytic reactions as catalysts or ligands, in electrochemistry for their redox potentials, in materials chemistry for their optical and electronic properties. The principal family of organometallic compounds of this thesis is ferrocene due to its physical and chemical properties particularly its robustness and the possibility of multiple substitutions on cyclopentadienyl ligands, the dissymmetric functionalization of these cyclopentadienyl rings being a major challenge.The first part of this thesis describes the bibliography o…
Synthesis, characterization and the first crystal structure of the Zn(II) complex of 4,6-O-ethylidine-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine
2001
4,6-O-Ethylidine-N-(2-hydroxybenzylidene)-β-D-glucopyranosylamine (H3L1) and N-(5-bromo-2-hydroxybenzylidene-4,6-O-ethylidine-β-D-glucopyranosylamine (H3L2) molecules possessing a–C-1–N=C(H)–moiety for metal-ion binding were synthesized by condensing the 4,6–O–ethylidene–β–D–glucopyranosylamine with salicylaldehyde or 5–bromosalicylaldehyde. Complexes of these ligands with Zn(II) were isolated and characterized using elemental analysis, FTIR, UV–Vis absorption, NMR spectroscopic and FAB mass spectrometric techniques. The structure of the Zn(II) complex derived from H3L1 was established for the first time by a single-crystal X-ray diffraction study. The anomeric nature of the saccharide moie…
A novel thermodynamic approach for the complexation study of toxic metal cations by a landfill leachate
2018
Landfill leachates can contaminate nearby aquifers. The hazards deriving from this contamination also depend on the chemical speciation of various contaminants. A novel approach is proposed here to face this problem from a chemical thermodynamics point of view. The complexing ability of the soluble fraction of a landfill leachate (collected from Bellolampo, Palermo, Italy) towards Pb2+, Cd2+ and Cu2+ has been investigated at T = 298.15 K in NaClaq at I = 0.1 mol dm−3. The soluble fraction of the landfill leachate was first characterized by different analytical techniques. Then, its acid–base properties were studied by ISE-H+ potentiometric titrations and modelled by the so-called diprotic-l…
Sequestration of organometallic compounds by natural organic matter. binding of trimethyltin(IV) by fulvic and alginic acids
2006
The binding capacity of fulvic and alginic acids towards trimethyl tin(IV) cation was quantitatively determined in order to evaluate the sequestering ability of toxic organometallic compounds by natural organic matter. Investigations were performed in the pH range of natural waters (5–8.5) where the carboxylate groups, largely present in both sequestering agents, are the main binding sites. A chemical interaction model, according to which both the protonation of polyelectrolyte ligands and the hydrolysis of the organotin cation in NaCl aqueous solution were considered, was used to define the speciation of the systems under investigation. Measurements performed at different ionic strength va…
Sequestration of alkyltin(IV) cations by complexation with amino-polycarboxylic chelating agents
2013
Abstract The binding capacity of four amino-polycarboxylic ligands (APCs) [nitrilotriacetate (NTA), ethylenediamine- N , N , N′ , N′ -tetraacetate (EDTA), (S,S)-ethylenediamine- N , N ′-disuccinic acid (S,S-EDDS) and diethylenetriamine- N , N , N′ , N″ , N″ -pentaacetate (DTPA)] towards mono-, di- and tri-alkyltin(IV) cations [(CH 3 )Sn 3 + , (CH 3 ) 2 Sn 2 + , (C 2 H 5 ) 2 Sn 2 + , (CH 3 ) 3 Sn + or (C 2 H 5 ) 3 Sn + ] was studied, in aqueous solutions, by ISE-H + potentiometry, at I = 0.1 mol L − 1 (NaCl) and at T = 298.15 K. In all the systems R x Sn (4 − x)+ − APC (R = CH 3 or C 2 H 5 ) a strong 1:1 species is formed together with protonated, hydroxo and dinuclear complexes. The valu…
Synthesis and studies of new optimised chelating agents for targeting chemokine receptor CXCR4
2012
The objective of this thesis work was to develop CXCR4-targeted tools to localize and treat cancer at an early stage. In this line, we investigated the synthesis of new target-specific radiopharmaceuticals. The work focused on two main axes, i.e. the chelating agent and the carrier, by using the know-how and the expertise of our group in polyazacycloalkanes synthesis and functionalization. In the first part, we were interested in developing new macrocyclic scaffolds of high potential for copper and gallium chelation. We first focused on the development of a new powerful route towards selectively functionalized constrained homocyclens. The second part was based on C-functionalized 1,4,7-tria…
Inclusion complexes of Cethyl-2-methylresorcinarene and pyridine N-oxides: breaking the C–I⋯−O–N+ halogen bond by host–guest complexation
2016
C ethyl-2-Methylresorcinarene forms host–guest complexes with aromatic N-oxides through multiple intra- and intermolecular hydrogen bonds and C–H⋯π interactions. The host shows conformational flexibility to accommodate 3-methylpyridine N-oxide, while retaining a crown conformation for 2-methyl- and 4-methoxypyridine N-oxides highlighting the substituent effect of the guest. N-Methylmorpholine N-oxide, a 6-membered ring aliphatic N-oxide with a methyl at the N-oxide nitrogen, is bound by the equatorial −N–CH3 group located deep in the cavity. 2-Iodopyridine N-oxide is the only guest that manifests intermolecular N–O⋯I–C halogen bond interactions, which are broken down by the host resulting i…
Host-guest complexes of conformationally flexible
2018
Host–guest complexes of C-hexyl-2-bromoresorcinarene (BrC6) with twelve potential aromatic N-oxide guests were studied using single crystal X-ray diffraction analysis and 1H NMR spectroscopy. In the solid state, of the nine obtained X-ray crystal structures, eight were consistent with the formation of BrC6-N-oxide endo complexes. The lone exception was from the association between 4-phenylpyridine N-oxide and BrC6, in that case the host forms a self-inclusion complex. BrC6, as opposed to more rigid previously studied C-ethyl-2-bromoresorcinarene and C-propyl-2-bromoresorcinarene, undergoes remarkable cavity conformational changes to host different N-oxide guests through C–H···π(host) intera…