Ga complexes of 8-hydroxyquinoline-2-carboxylic acid: Chemical speciation and biological activity.

The binding ability of 8-hydroxyquinoline-2-carboxylic acid (8-HQA) towards Ga has been investigated by ISEH (Ion Selective Electrode, glass electrode) potentiometric and UV/Vis spectrophotometric titrations in KCl at I = 0.2 mol dm and at T = 298.15 K.

A tutorial on potentiometric data processing. Analysis of software for optimization of protonation constants.

Defining the distribution of the chemical species in a multicomponent system is a task of great importance with applications in many fields. To clarify the identity and the abundance of the species that can be formed by the interaction of the components of a solution, it is fundamental to know the formation constants of those species. The determination of equilibrium constants is mainly performed through the analysis of experimental data obtained by different instrumental techniques.

Silver(I) pyrrole- and furan-2-carboxylate complexes - From their design and characterization to antimicrobial, anticancer activity, lipophilicity and SAR.

Two silver(I) complexes with biologically relevant heterocyclic ligands, pyrrole and furan-2- carboxylic acid, were synthesized and their composition was confirmed using elemental, spectral, thermal and structural analyses. The {[Ag(Py2c)]} (AgPy2c, Py2c = pyrrole-2-carboxylate) and {[Ag(Fu2c)]} (AgFu2c, Fu2c = furan-2-carboxylate) solubility and stability in biological test stock solution were confirmed by H NMR spectroscopy. The X-ray analysis has enabled us to determine typical argentophilic interactions and bridging carboxylate coordination mode of both ligands.

Caffeic Acid/Eu(III) Complexes: Solution Equilibrium Studies, Structure Characterization and Biological Activity.

Caffeic acid (CFA) is one of the various natural antioxidants and chemoprotective agents occurring in the human diet. In addition, its metal complexes play fundamental roles in biological systems. Nevertheless, research on the properties of CFA with lanthanide metals is very scarce, and little to no chemical or biological information is known about these particular systems.

The Solution Behavior of Dopamine in the Presence of Mono and Divalent Cations: A Thermodynamic Investigation in Different Experimental Conditions.

The interactions of dopamine [2-(3,4-Dihydroxyphenyl)ethylamine, (Dop)] with methylmercury(II) (CHHg), 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 Sn we observed the formation of binuclear complexes (ML and MLOH (charge omitted for simplicity); M = Sn, L = Dop).

Evaluation of adsorption ability of cyclodextrin-calixarene nanosponges towards Pb ion in aqueous solution.

Different cyclodextrin-calixarene nanosponges (CyCaNSs) have been characterized by means of FFC-NMR relaxometry, and used as sorbents to remove Pb ions from aqueous solutions. Considering that the removal treatments may involve polluted waters with different characteristics, the adsorption experiments were performed on solutions without and with the addition of background salts, under different operational conditions. The adsorption abilities and affinities of the nanosponges towards Pb ions were investigated by measuring the metal ion concentration by means of Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) and Differential Pulse Anodic Stripping Voltammetry (DP-ASV).

Iron Coordination Properties of Gramibactin as Model for the New Class of Diazeniumdiolate Based Siderophores.

Gramibactin (GBT) is an archetype for the new class of diazeniumdiolate siderophores, produced by Paraburkholderia graminis, a cereal-associated rhizosphere bacterium, for which a detailed solution thermodynamic study exploring the iron coordination properties is reported. The acid-base behavior of gramibactin as well as its complexing ability toward Fe was studied over a wide range of pH values (2≤pH≤11). For the latter the ligand-competition method employing EDTA was used.

Interaction of N-acetyl-l-cysteine with Na, Ca, Mg and Zn. Thermodynamic aspects, chemical speciation and sequestering ability in natural fluids.

The estimation of thermodynamic parameters of N-Acetyl-L-cysteine (NAC) protonation were determined in NaCl, (CH)NCl, (CH)NI employing various temperature and ionic strengths conditions, by potentiometric measurements. The interaction of NAC with some essential metal cations (, Ca, Mg and Zn) was investigated as well at 298.15 K in NaCl in the ionic strength range 0.

8-Hydroxyquinoline-2-Carboxylic Acid as Possible Molybdophore: A Multi-Technique Approach to Define Its Chemical Speciation, Coordination and Sequestering Ability in Aqueous Solution.

8-hydroxyquinoline-2-carboxylic acid () has been found in high concentrations (0.5-5.0 mmol·dm) in the gut of Noctuid larvae (and in a few other lepidopterans), in which it is proposed to act as a siderophore.

Understanding the Solution Behavior of Epinephrine in the Presence of Toxic Cations: A Thermodynamic Investigation in Different Experimental Conditions.

The interactions of epinephrine (()-(-)-3,4-dihydroxy-α-(methylaminomethyl)benzyl alcohol; ) with different toxic cations (methylmercury(II): CHHg; dimethyltin(IV): (CH)Sn; dioxouranium(VI): UO) were studied in NaCl at different ionic strengths and at = 298.15 K ( = 310.15 K for (CH)Sn).

A critical approach to the toxic metal ion removal by hazelnut and almond shells.

The adsorption capacity of ground hazelnut (HS) and almond (AS) shells towards Pb(II) and Cd(II) has been studied at pH = 5, in NaNO and NaCl ionic media, in the ionic strength range 0.05-0.5 mol L.

Pb(II) adsorption by a novel activated carbon - alginate composite material. A kinetic and equilibrium study.

The adsorption capacity of an activated carbon - calcium alginate composite material (ACAA-Ca) has been tested with the aim of developing a new and more efficient adsorbent material to remove Pb(II) ion from aqueous solution. The study was carried out at pH=5, in NaCl medium and in the ionic strength range 0.1-0.

Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.

SALMO and S3M: A Saliva Model and a Single Saliva Salt Model for Equilibrium Studies.

A model of synthetic saliva (SALMO, SALiva MOdel) is proposed for its use as standard medium in in vitro equilibrium and speciation studies of real saliva. The concentrations come out from the literature analysis of the composition of both real saliva and synthetic saliva. The chief interactions of main inorganic components of saliva, as well as urea and amino acids, are taken into account on the basis of a complex formation model, which also considers the dependence of the stability constants of these species on ionic strength and temperature.

Chelating agents for the sequestration of mercury(II) and monomethyl mercury(II).

Both mercury(II) and monomethyl mercury(II) poisonings are of great concern for several reasons. As it happens for other metals, chelation therapy is the most indicated treatment for poisoned patients. The efficacy of the therapy and the reduction of side-effects can be sensibly enhanced by an accurate knowledge of all the physiological mechanisms involved in metal uptake, transport within and between various tissues, and (possibly) clearance.

Speciation of cadmium in the environment.

This chapter reports an analysis of literature dedicated to the speciation of cadmium in various environmental compartments, i.e., atmosphere, natural waters, soils and sediments.

Modeling solubility, acid-base properties and activity coefficients of amoxicillin, ampicillin and (+)6-aminopenicillanic acid, in NaCl(aq) at different ionic strengths and temperatures.

The total solubility of three penicillin derivatives was determined, in pure water and NaCl aqueous solutions at different salt concentrations (from ∼0.15 to 1.0 mol L(-1) for ampicillin and amoxicillin, and from ∼0.

Sequestering ability of phytate toward biologically and environmentally relevant trivalent metal cations.

Quantitative parameters for the interactions between phytate (Phy) and Al(3+), Fe(3+), and Cr(3+) were determined potentiometrically in NaNO(3) aqueous solutions at I = 0.10 mol L(-1) and T = 298.15 K.

Modeling the acid-base properties of glutathione in different ionic media, with particular reference to natural waters and biological fluids.

The acid-base properties of γ-L-glutamyl-L-cysteinyl-glycine (glutathione, GSH) were determined by potentiometry (ISE-H(+), glass electrode) in pure NaI((aq)) and in NaCl((aq))/MgCl(2(aq)), and NaCl((aq))/CaCl(2(aq)) mixtures, at T = 298.15 K and different ionic strengths (up to I(c) ~ 5.0 mol L(-1)).

Sequestration of Alkyltin(IV) compounds in aqueous solution: formation, stability, and empirical relationships for the binding of dimethyltin(IV) cation by N- and O-donor ligands.

The sequestering ability of polyamines and aminoacids of biological and environmental relevance (namely, ethylenediamine, putrescine, spermine, a polyallylamine, a branched polyethyleneimine, aspartate, glycinate, lysinate) toward dimethyltin(IV) cation was evaluated. The stability of various dimethyltin(IV) / ligand species was determined in NaCl(aq) at t = 25 degrees C and at different ionic strengths (0.1 View Article and Find Full Text PDF

Enhancement of hydrolysis through the formation of mixed hetero-metal species.

In order to analyze the formation of hetero-metal polynuclear hydrolytic species, in this paper, we reported some results of an investigation (at I = 0.16molL(-1) in NaNO(3), at t = 25 degrees C by potentiometry, ISE-H(+), glass electrode) on the hydrolysis of several mixtures (in different ratios) of two couples of cations: dioxouranium(VI)/copper(II) and dioxouranium(VI)/diethyltin(IV). The elevated total concentrations of cations 0.

Speciation of phytate ion in aqueous solution. Trimethyltin(IV) interactions in self medium.

In this paper the results of a potentiometric (ISE-[H+] glass electrode) investigation at t = 25 degreesC on the complexing ability of phytate towards trimethyltin(IV) (tmt) and on the acid-base properties of tmt at high metal concentration (0.050 and 0.075 mol L(-1)) are reported.

Dioxouranium(VI)-carboxylate complexes. Speciation of UO2(2+)-1,2,3-propanetricarboxylate system in NaCl(aq) at different ionic strengths and at t=25 degrees C.

The formation constants of dioxouranium(VI)-1,2,3-propanetricarboxylate [tricarballylate (3-), TCA] complexes were determined in NaCl aqueous solutions at 0 < or = I/mol L(-1) < or = 1.0 and t=25 degrees C, by potentiometry, ISE-[H+] glass electrode. The speciation model obtained at each ionic strength includes the following species: ML-, MLH0, ML2(4-) and ML2H3- (M = UO2(2+) and L = TCA).

Speciation of phytate ion in aqueous solution. Protonation constants and copper(II) interactions in NaNO3aq at different ionic strengths.

The acid base behavior of phytate has been studied (at t=25 degrees C by potentiometry, ISE-H+ glass electrode) in NaNO3aq at different ionic strengths (0.1 < or = I/mol L(-1) < or = 1.0).