D-metal Cations Research Articles

1H NMR study of kinetics of the Ni(II) and Zn(II) cations complex formation with 2-aza-5,10,15,20-tetraphenyl-21-carbaporphyrin

The methodology of 1H NMR study of the kinetics of the Ni(II) and Zn(II) cations complex formation with 2-aza-5,10,15,20-tetraphenyl-21-carbaporphyrin ([2-N, 21-CH]TPP I) was developed. The processes rate constants are determined using the pseudo-first and pseudo-second order models. It was shown that this methodology allows for identification and evaluation with high accuracy of the effects of donor–acceptor and solvation interactions that occur in the processes of the d-metal cations complex formation with the inverted tetrapyrrole macrocyclic ligands.

Analysis of Sorption Activity of Apple Pectin Modified with Organic Pharmacophores in Relation to d-Metal Cations (Cu2+, Co2+, and Mn2+)

Analysis of Sorption Activity of Apple Pectin Modified with Organic Pharmacophores in Relation to d-Metal Cations (Cu2+, Co2+, and Mn2+)

INFLUENCE OF CERTAIN D-METALS ON FORMATION OF ADVANCED GLYCATION END PRODUCTS, AGGREGATION AND AMYLOID TRANSFORMATION OF ALBUMIN IN GLYCATION REACTION

The aim of the research is to investigate the influence of the factor of the glycation behavior of bovine serum albumin (BSA) by glucose, and the factor of d-metal cations (nickel (II), cobalt (II), iron (II), iron (III), copper (II) or zinc (II)) presence, on the process of aggregation and the amyloid transformation of BSA and, therefore, to establish the effect of these cations on the rate of the formation of advanced glycation end products (AGEs), and the intensity of fluorescence of the amino acids tyrosine and tryptophan.Materials and methods. Reagents in the glycation are: glucose (at the final concentration of 0.36 M), BSA (at the final concentration of 1 mg/ml), deionized water, one of the d-metal cations, i. e. nickel (II), cobalt (II), iron (II), iron (III), copper (II) or zinc (II) (in the form of chloride, sulfate or nitrate salts, at the final concentration of 40 μM). The conditions for the glycation reaction are the incubation for 24 hours at the temperature of 60°C. The influence of two factors (the factor of the glycation reaction and the factor of a d-metal ion presence in the reaction medium) on the concentration of glycation end products (AGEs) formed during the glycation reaction, on the fluorescence intensity of the amino acids tryptophan and tyrosine, on the aggregation of BSA, and on the ability of BSA to the amyloid transformation under the described conditions, have been studied.Results. It was found out that the studied factors have a statistically significant effect on the considered parameters. The highest activity was found for the copper ion (II), which intensifies the formation of the AGEs in the samples where glycation occurs, reduces the fluorescence intensity of the amino acids’ tryptophan and tyrosine (independently and increasing the effect against the background of glycation). Besides, it independently causes the aggregation of BSA hereby intensifying the effect against the background of glycation, it independently causes the amyloid transformation of BSA enhancing the effect against the background of glycation. The above-listed effects were the least pronounced in the reaction media with the addition of nickel (II) or cobalt (II). These cations reduce the rate of the AGEs formation, do not cause the formation of protein aggregates. In the presence of glucose, nickel (II) weakly suppresses the fluorescence intensity of tryptophan and tyrosine, and slightly enhances the amyloid transformation of BSA. Cobalt (II) slightly inhibits the amyloid transformation of BSA. In terms of the severity and nature of the effects, the iron (II), iron (III) and zinc (II) cations occupy an intermediate position between copper (II), on the one hand, and nickel (II) and cobalt (II), on the other hand, combining the influence on the AGEs formation, the intensity of fluorescence of tryptophan and tyrosine, the aggregation and amyloid transformation of BSA. In the absence of glucose, the ability of zinc (II) to induce the formation of protein aggregates turned out to be the highest, and its ability to stimulate the amyloid transformation of BSA corresponded to that of copper (II).Conclusion. The presence of d-metal cations affects the rate of the AGEs formation in the glycation reaction, affects the rate of the BSA amyloid transformation and the protein aggregates formation. Among such ions as nickel (II), cobalt (II), iron (II), iron (III), copper (II) and zinc (II), copper (II) ions turned out to be the most active in their ability to accelerate the AGEs formation, suppress the fluorescence of tryptophan and tyrosine, enhance the aggregation and amyloid transformation of BSA in the glycation reaction. The least manifestation of these properties is observed for nickel (II) and cobalt (II) ions.

Catechol-Containing Schiff Bases on Thiacalixarene: Synthesis, Copper (II) Recognition, and Formation of Organic-Inorganic Copper-Based Materials.

For the first time, a series of catechol-containing Schiff bases, tetrasubstituted at the lower rim thiacalix[4]arene derivatives in three stereoisomeric forms, cone, partial cone, and 1,3-alternate, were synthesized. The structure of the obtained compounds was proved by modern physical methods, such as NMR, IR spectroscopy, and HRMS. Selective recognition (Kb difference by three orders of magnitude) of copper (II) cation in the series of d-metal cations (Cu2+, Ni2+, Co2+, Zn2+) was shown by UV-vis spectroscopy. Copper (II) ions are coordinated at the nitrogen atom of the imine group and the nearest oxygen atom of the catechol fragment in the thiacalixarene derivatives. High thermal stable organic-inorganic copper-based materials were obtained on the base of 1,3-alternate + Cu (II) complexes.

Sorption of d-metal cations by keratin from aqueous solutions

The Cu2+, Cd2+, Ni2+ and Zn2+ metal ions sorption by wool keratin was evaluated from the thermodynamic and kinetic points of view. The experimental data had a very good fit with Langmuir, Freundlich and Dubinin-Radushkevich isotherm models, and the best coefficient of determination was deduced by Langmuir isotherm having value 0.99. The process kinetics was evaluated by intraparticle diffusion model, pseudo-first and pseudo-second order kinetic models, the latter showing the highest correlation with the experimental data. The temperature effect on sorption of Cu2+, Ni2+, Cd2+ and Zn2+ ions from aqueous solutions was determined within a range of adsorption temperatures (283–353 K). The endothermic effect of heavy metal ions sorption by zwitter-ionic form of wool keratin (+H3N-)W(−COO−) indicates that there is a superposition of the sorption process which runs with participation of amino- and carboxyl groups. Acidic keratin groups in the anionic form are involved in the sorption of metal cations, and the amino groups being in the cationic H-form are participated in the sorption of anions to form salt structures [SO42−(+H3N-)2]W[(−COO)2M]. A competitive sorption between doubly- and singly-charged metal cations (M2+/2M+) according to the ion exchange mechanism on the same acid sorption centers of the sorbent was observed. FTIR analysis demonstrated the formation of complexes between Cu2+ and keratin sorption centers that involve terminal free carboxyl groups of amino acids of wool. The chelate structures with metal complexes on acidic sorption sites were computed with the methods of quantum chemistry on modeled compounds, by adhering to chemistry’s best practices.

Higher Quaternary Ammonium Salts with a Sterically Hindered Exchange Center: Application to the Development of Ion Selective Electrodes Reversible to Metal Thiocyanate Complexes

Ion-selective electrodes based on a sterically hindered higher quaternary ammonium salt, 3,4,5-trisdodecyloxybenzyltrioctadecylammonium bromide, and a plasticizer, 1-bromonaphthalene, reversible to zinc and cobalt thiocyanate complexes, are developed. They are characterized by high analytical performance. The selective determination of zinc and cobalt on their simultaneous presence is achieved by varying the concentration of ligands (thiocyanate ions) in the supporting electrolyte. The mechanism of the coordination of thiocyanate ions with some d-metal cations was studied by IR spectroscopy. It is shown that zinc and cobalt coordinate SCN– ions by the isothiocyanate type, because of which $${\text{Zn(NCS}})_{4}^{{2 - }}$$ and $${\text{Co(NCS)}}_{{\text{4}}}^{{{\text{2}} - }}$$ ions have a high anion-exchange affinity to the membrane phase. The developed electrodes were used to determine zinc and cobalt in cheese, potatoes, and beets.

Metal exchange reaction of cadmium meso-triaza-β-tetra-(4-tert-butylbenzo)porphyrinate with metal salts in dimethyl sulfoxide

The metal exchange reactions between cadmium meso-triaza-β-tetra-(4-tert-butylbenzo)porphyrinate (Cd-3N(t-BuBz)P) and copper and zinc chlorides in dimethyl sulfoxide were studied by spectrophotometry. The kinetic and energy parameter of the reactions were determined. The results of the metal exchange reaction were compared with those for the reactions of formation Zn-3N(t-BuBz)P and Cu-3N(t-BuBz)P, which were obtained by the interaction of meso-triaza-β-tetra-(4-tert-butylbenzo)porphine (H2-3N(t-BuBz)P) with the corresponding d-metal cations.

The role of transition metal cations in dyeing of fabrics made from synthetic fibres

The use of d-metal cations in dyeing polyester fabric with dark blue K increases the dyeability to 350%. Use of VO2+, Fe2+, and Cu2+ cations is most effective. It is hypothesized that d-metal cations increase the number of active sites due to vacant atomic orbitals on the valence level so that the polyester fibre can sorb a larger amount of dye. The use of d-metal cations in dyeing polyester fabric increases the resistance of the color to external physicochemical effects.

Complexation in aqueous solutions of lignosulfonates

The capability of lignosulfonates for donor-acceptor interaction with d-metal cations in aqueous solutions was studied. A quantitative estimation of the complexing properties of lignosulfonates was made.

The influence of low- and high-molecular chelating additives upon the reduction of nitrotetrazolium blue to formazane in the presence of d-metal cations

The influence of high- and low-molecular additives upon the reduction of nitrotetrazolium blue to formazane in the presence of d-metal cations was studied. It was shown that the introduction of chelating additives did not essentially change the earlier found regularities in the variation of anti- and prooxidant activity within the range of d-metal cations. In most cases the observed effects may be understood in the terms of the theory of hard and soft acids and bases.

Synthesis and sorption properties of layered hydrous manganese dioxide saturated with s-, p-, and d-metal cations

Layered compounds based on hydrous manganese dioxide (hereafter, Mn-phases) saturated with s-metal (Ba2+), p-metal (Pb2+), and d-metal (Mn2+, Co2+, Ni2+, Cu2+, Zn2+, and Cd2+) cations, analogues of manganese minerals of oceanic ferromanganese formations (vernadite, birnessite, buserite-I, and asbolan), were prepared at 4–6°C. All Mn-phases have poorly ordered structures. The sorption properties of phase compounds were studied in relation to alkali-metal (Na+ and K+) and other s-, p-, and d-metal cations. The exchange capacities of Mn-phases for alkali cations are very low, within 0.02–0.10 mg-equiv/g; for the other cations, the exchange capacities are 0.13–4.20 mg-equiv/g. The sorption of divalent metal cations depends on the phase and chemical composition of the Mn-phase.

Self-assembly of nanosized aggregates based on the photoswitchable p-tert-butyl thiacalix[4]arene derivative and Fe III, CuII, and AgI cations

New p-tert-butyl thiacalix[4]arene tetrasubstituted at the lower rim and containing the azobenzene fragments in the 1,3-alternate configuration was synthesized. Its receptor properties with respect to d-metal cations (Fe 3+, Cu2+, Ag+) were studied using UV spectroscopy and dynamic light scattering (DLS). The ability of p-tert-butyl thiacalix[4]arene to molecular recognition of silver cations was estimated by UV spectroscopy. The aggregation of these systems was studied by the dynamic light scattering method.

Effect of d-metal cations on the reduction of nitrotetrazolium blue to formazan

A method is suggested for quantitative assessment of the anti-/prooxidant activity of d-metal cations by their effect of the rate of the reduction of nitrotetrazolium blue to formazan in a system generating the superoxide radical anion in the presence of reduced nicotinamide adenine dinucleotide (NADH2). The effect of the acidity of the medium on the anti/prooxidant activity of cations, as well as correlations between the ionization potentials, ionic radii, and antioxidant properties of cations are analyzed.

Layered hydrous manganese dioxide saturated with alkaline-earth cations: Synthesis and sorption properties

Layered compounds based on hydrous manganese dioxides (hereafter, Mn-phases) saturated with alkaline-earth cations were synthesized at 3–6°C. These phases are analogues of manganese minerals from oceanic iron-manganese sediments (vernadite, birnessite, buserite-I, an asbolan-like phase, and a hybrid phase). All the Mn-phases, as a rule, had poorly ordered structures. The sorption properties of these phases were studied with respect to alkali-metal cations (Na+, K+), an s-metal cation (Ba2+), a p-metal cation (Pb2+), and d-metal cations (Mn2+, Co2+, Ni2+, Cu2+, Zn2+ and Cd2+). The exchange capacities of the Mn-phases were 0.45–1.06 mg-equiv/g for the alkali cations and 0.94–5.78 mg-equiv/g for the other cations. The phase composition of the Mn-phase did not affect the alkali cation sorption but affected the divalent cation sorption. The divalent cation exchange capacity increased from well-ordered birnessite to poorly ordered vernadite.

Photochromic Cation Sensors

ABSTRACT Novel photochromic chemosensors for alkali-, alkali-earth and d-metal cations were synthesized and their photochemical and complexing properties investigated with the use of UV/vis, IR, 1H/7Li NMR spectroscopy and quantum chemical calculations – DFT(B3LYP/6-31G).

Phase transitions and diffusion kinetics during Mg2+- and Li+-ion insertions into the Mo6S8 chevrel phase compound studied by PITT

Careful potentiostatic intermittent titrations (PITT) were performed in order to study Li+- and Mg2+-ion insertions into the Mo6S8 chevrel phase compound. Potential dependences of equilibrium and dynamic characteristics of the insertion processes, such as the differential intercalation capacitance, Cdif, the chemical diffusion coefficient, D, and the specific ionic conductivity, κ, were measured and interpreted in terms of lattice-gas models with highly attractive interactions between the inserted ions. Li-ion conductivity of the slightly intercalated chevrel phase is much higher than that of Mg-ions, which can be attributed to a higher charge density of the latter ion and to its higher polarization effect on the S8 anions’ lattice of the host material. Some crystallographic arguments related to the low mobility of the Mg-ion on the one hand, and the extremely high mobility of most of the divalent d-metal cations in the Mo6S8 chevrel phase on the other hand, are discussed.

Phase transitions and diffusion kinetics during Mg 2+- and Li +-ion insertions into the Mo 6S 8 chevrel phase compound studied by PITT

Careful potentiostatic intermittent titrations (PITT) were performed in order to study Li +- and Mg 2+-ion insertions into the Mo 6S 8 chevrel phase compound. Potential dependences of equilibrium and dynamic characteristics of the insertion processes, such as the differential intercalation capacitance, C dif, the chemical diffusion coefficient, D, and the specific ionic conductivity, κ, were measured and interpreted in terms of lattice-gas models with highly attractive interactions between the inserted ions. Li-ion conductivity of the slightly intercalated chevrel phase is much higher than that of Mg-ions, which can be attributed to a higher charge density of the latter ion and to its higher polarization effect on the S 8 anions’ lattice of the host material. Some crystallographic arguments related to the low mobility of the Mg-ion on the one hand, and the extremely high mobility of most of the divalent d-metal cations in the Mo 6S 8 chevrel phase on the other hand, are discussed.