Some New Organoantimony(V) Compounds

A series of antimony(V) compounds containing bifunctional ligands has been prepared. These compounds are of the structure (C₆H₅)₃ Sb (OOCR)₂ and (R = P ? C₆H₄OH₅ o-C₆X₄COOMe and cis-CX=CX where X = H, Cl and Br). These are the first antimony(V) compounds which contain functional reactive end groups.     

Electrolytic preparation of an isomer pair of cobalt (III) mixed complexes

The electrolytic preparation of some coordination compounds of cobalt (III), such as the amino-, sulphato- and acetato-complexes, had already been described [1–5]: the presence of the ligand in the electrolysed solution stabilizes the + 3 oxidation state of cobalt, which is generated anodically. All the cobalt (III) complexes prepared up to date by electrochemical methods contain various numbers of the same ligand group, without having regard to the coordinated water molecules. In this note we deal with the electrolytic preparation of two mixed complexes of cobalt (III),cis- andtrans-[Co en₂ (OCOCH₃)₂]ClO₄, where en=ethylenediamine.Work carrid out with the aid of C.N.R. (Consiglio Nazionale delle Ricerche).     

Permeability of ethanol solution through poly(lactic acid) film

The permeation properties of ethanol solution through poly(lactic acid) (PLA) films were investigated. The total flux of ethanol solution through PLA films was strongly depended on the flux of water. In addition, the diffusion coefficient of water was 1000 times higher than that of ethanol, and decreased with increasing feed concentration. After the permeation measurement, crystallization (X_C‐DSC = 1–2%) was observed. However, the crystallinity was not dependent on the feed concentration. On the other hand, the mole ratio of ethanol and water molecules in the PLA film strongly depended on the feed concentration. Based on the results, we concluded that the interaction with ethanol molecules caused the decrease in diffusion coefficient of water in PLA film. Thus, the permeation mechanism of the ethanol solution to the PLA film was investigated in detail. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42031.     

Selectively removal of Al(III) from Pr(III) and Nd(III) rare earth solution using surface imprinted polymer

Rare earth is a very important strategic resource. But, impurities, such as Al³⁺, have great influence on the properties of rare earth material. In this paper, an Al³⁺-ionic imprinted polyamine functionalized silica gel sorbent was prepared by a surface imprinting technique for selectively adsorbing Al³⁺ from rare earth solution. The adsorption and recognition properties of IIP-PEI/SiO₂ for Al³⁺ were studied in detail. The experimental results showed that IIP-PEI/SiO₂ possessed strong adsorption affinity, specific recognition ability, and excellent selectivity for Al³⁺. The adsorption isotherm data greatly obey the Langmuir model, and the adsorption was typical monolayer. The adsorption capacity could reach to 1.98 mmol g^?1, and relative selectivity coefficients relative to Pr³⁺ and Nd³⁺ are 23.47 and 22.85, respectively. Besides, IIP-PEI/SiO₂ was regenerated easily using diluted hydrochloric acid solution as eluent and IIP-PEI/SiO₂ possesses better reusability.     

Synthesis of Solid Phosphate Compounds of Ti(III) and Ti(IV)

Several new methods for the synthesis of TiPO₄ are described. Crystalline phosphate compounds containing boron and titanium in a single III or mixed (III, IV) oxidation states have been synthesized and identified by X-ray diffraction. An additional family of phosphate compounds containing only Ti(III, IV) has also been synthesized and identified. All the compounds exhibit attractive colors, e.g., bright green, blue, purple, and black, and are stable at room temperature in air and in boiling water.     

Preparation and Properties of Monodispersed Colloidal Particles of Lanthanide Compounds: III, Yttrium(III) and Mixed Yttrium(III)/Cerium(III) Systems

Colloidal dispersions of uniform spherical particles of yttrium basic carbonate and rodlike particles of yttrium ammine carbonate were prepared by aging at elevated temperatures yttrium salt solutions in the presence of urea. Different composition and morphology were achieved by altering the aging temperature and time. Coprecipitation in mixed solutions of yttrium(III) and cerium(III) salts under similar experimental conditions yielded composite spherical particles of basic carbonate. The content of the two metals in the solids followed closely the initial composition of the reacting solutions. On calcination all prepared solids converted to their corresponding oxides while retaining their particle morphology. The so-prepared powders were characterized by various techniques.     

Aquaporin Inhibition by Gold(III) Compounds: New Insights

Aquaporins (AQPs) are membrane water/glycerol channels with essential roles in biological systems, as well as being promising targets for therapy and imaging. Using a stopped‐flow method, a series of gold(III), platinum(II) and copper(II) complexes bearing nitrogen donor ligands, such as 1,10‐phenatroline, 2,2′‐bipyridine, 4,4′‐dimethyl‐2,2′‐bipyridine, 4,4′‐diamino‐2,2′‐bipyridine and 2,2′;6′,2“‐terpyridine, were evaluated in human red blood cells expressing AQP1 and AQP3, responsible for water and glycerol movement, respectively. The results showed that the gold(III) complexes selectively modulate AQP3 over AQP1. Molecular modeling and density functional theory (DFT) calculations were subsequently performed to rationalize the observations and to investigate the possible molecular mechanism through which these gold compounds act on their putative target (AQP3). In the absence of any crystallographic data, a previously reported homology model was used for this purpose. Combined, the findings of this study show that potent and selective modulation of these solute channels is possible, however further investigation is required into the selectivity of this class of agents against all AQP isoforms and their potential therapeutic uses.     

Novel Unsymmetrical Ru(III) and Mixed-valence Ru(III)/Ru(II) Dinuclear Compounds Related to the Antimetastatic Ru(III) Drug NAMI-A

In this paper we report the stepwise preparation and the characterization of new unsymmetrical monoanionic Ru(III) dinuclear compounds, [NH(4)][{trans-RuCl(4)(Me(2)SO-S)}(mu-L){mer-RuCl(3)(Me(2)SO-S)(Me(2)SO-O)}] (L = pyz (1), pym (2)). By a similar synthetic approach we also prepared new mixed-valence Ru(III)/Ru(II) dinuclear compounds of formula [NH(4)][{trans-RuCl(4)(Me(2)SO-S)}(mu-pyz){cis,cis,cis-RuCl(2)(Me(2)SO-S)(2)(CO)}] (L = pyrazine (pyz, 3), pyrimidine (pym, 4)). Moreover, we describe the chemical behavior of compounds 1-4 in physiological solution, also after complete reduction (with ascorbic acid) to the corresponding Ru(II)/Ru(II) species. Overall, the chemical behavior of 1 and 2 after reduction resembles that of the corresponding dianionic and neutral dinuclear species, [{trans-RuCl(3)(Me(2)SO-S)}(2)(mu-L)](2-)and [{mer-RuCl(3)(Me(2)SO-S)(Me(2)SO-O)}(2) (mu-L)]. On the other hand, the mixed-valence dinuclear compounds 3 and 4, owing to the great inertness of the cis,cis,cis-RuCl(2)(Me(2)SO-S)(2)(CO)(1/2mu-L) fragment, behave substantially like the mononuclear species [trans-RuCl(4)(Me(2)SO-S)(L)](-) in which the terminally bonded L ligand can be considered as bearing a bulky substituent on the other N atom.     

High selectivity and removal efficiency of lotus root-based activated carbon towards Fe(III) in La(III) solution

Rare earth elements are an important strategic resource. However, a trace of Fe(III) impurity has serious adverse impact on the performance of rare earth materials. We synthesized a novel nitrogen-containing carbon material, AC_LR-400, using lotus root as raw materials. The AC_LR-400 was characterized by surface area analyzer, elemental analysis and FT-IR. The selectivity and removal efficiency of AC_LR-400 towards Fe(III) were also investigated. The BET specific surface area of AC_LR-400 was 68.44 m²·g^?1, and the average pore diameter was 12.54 nm. With abundant nitrogen- containing functional groups and well-developed internal pore structure, AC_LR-400 possesses strong adsorption affinity, excellent selectivity and removal efficiency for Fe(III). The adsorption capacity of AC_LR-400 towards Fe(III) could reach to 0.46 mmol·g^?1, selectivity coefficient with respect to La(III) was 8.9, and removal efficiency was 99.61%. The adsorption isotherm data greatly obey the Freundlich isotherm. In addition, AC_LR-400 can be regenerated easily and possesses better regeneration ability and reusability.     

Behaviour of poly(β-hydroxybutyric acid) in dilute solution

The refractive indices of poly(β-hydroxybutyric acid) (PHB) at four wavelengths have been determined via different procedures. Viscometric and light scattering measurements have been made on solutions of eight samples of PHB (M_w = 20·9 × 10³?929 × 10³ g mol^?1) in 2,2,2-trifluoroethanol. From the dependences of intrinsic viscosity and of radius of gyration on molar mass, the conformation of PHB in dilute solution is shown to be that of a random coil. The findings are discussed in relation to existing conflicting evidence on the conformation of this polymer.     

膜电解法再生碳酸钾脱碳溶液(英文)

In this work, the regeneration mechanism of potassium carbonate solution after absorption of CO2 using ion-exchange membrane electrolysis was presented. The solutions of potassium carbonate (K2CO3) and potassium bicarbonate (KHCO3) were used to simulate the solution after absorbing CO2. Experiments were carried out at various electrodes, temperatures and current densities. The results indicate that the membrane electrolysis can increase concentration ratio of K2CO3 and KHCO3, and achieve 100% conversion. In this process, not only CO2 is desorbed from carbonate solution, but also hydrogen, as a byproduct, is generated at the cathode, which is the main contributor to reduce energy consumption. Thus, the membrane electrolysis is valuable in the regeneration of the K2CO3 absorbent.     

Water-Soluble Ruthenium(III)-Dimethyl Sulfoxide Complexes: Chemical Behaviour and Pharmaceutical Properties

In this paper we report a review of the results obtained in the last few years by our group in the development of ruthenium(III) complexes characterized by the presence of sulfoxide ligands and endowed with antitumor properties. In particular, we will focus on ruthenates of general formula Na[trans-RuCl(4)(R(1)R(2)SO)(L)], where R(1)R(2)SO = dimethylsulfoxide (DMSO) or tetramethylenesulfoxide (TMSO) and L = nitrogen donor ligand. The chemical behavior of these complexes has been studied by means of spectroscopic techniques both in slightly acidic distilled water and in phosphate buffered solution at physiological pH. The influence of biological reductants on the chemical behavior is also described. The antitumor properties have been investigated on a number of experimental tumors. Out of the effects observed, notheworthy appears the capability of the tested ruthenates to control the metastatic dissemination of solid metastasizing tumors. The analysis of the antimetastatic action, made in particular on the MCa mammary carcinoma of CBA mouse, has demonstrated a therapeutic value for these complexes which are able to significantly prolong the survival time of the treated animals. The antimetastatic effect is not attributable to a specific cytotoxicity for metastatic tumor cells although in vitro experiments on pBR322 double stranded DNA has shown that the test ruthenates bind to the macromolecule, causing breaks corresponding to almost all bases, except than thymine, and are able to cause interstrand bonds, depending on the nature of the complex being tested, some of which results active as cisplatin itself.     

Effect of Cr(III) solution chemistry on electrodeposition of chromium

This work provides a new insight into the interaction of urea with formate during the chromium electrodeposition from a sulphate-based Cr(III) solution. The influence of solution chemistry on chromium electrodeposition in a Cr(III) bath containing sodium formate and urea as complexing agents was studied by FT-IR, XPS and AFM. The results show that good quality Cr coatings may be obtained only in those cases when the secondary ligand with the carbamidic group predominates over urea in the electrolyte. This suggests that electrodeposition of good quality chromium deposit is possible due to the formation of active chromium–carbamid complexes [Cr(carbamid)_n(H₂O)_6-n ]³⁺. These complexes delay the formation of the stable oligomeric species, and thus provide a prolonged working lifetime in the Cr(III) formate-urea electrolyte.     

Removal of arsenic(III) from aqueous solution by concrete-based adsorbents

The present paper investigates the adsorption of arsenic(III) (As(III)) onto 2 concrete-based low-cost materials, i.e., Aerocrete and Vermiculite impregnated by ferric oxyhydroxide. Adsorption experiments were performed to study the effect of initial pH, initial concentration of As(III), contact time, and ions usually present in water. No significant effect of the initial pH on the adsorption of As(III) by Aerocrete and Vermiculite was observed at the pH range of 4–8. The As(III) removal efficiency decreased at a high initial pH (i.e., 10). The Langmuir isotherm showed that the maximum As(III) adsorption capacity of Aerocrete and Vermiculite is 15.15 and 13.51 mg/g, respectively, which is higher than that observed using titanium dioxide (i.e., 3.52 mg/g), at pH 7 and 24 ±1 °C. A pseudo-second order kinetic model fitted well the experimentally obtained kinetic data. This suggests that chemisorption most probably controls the adsorption of As(III) on Aeroctere and Vermiculite. Significantly, As(III) (1 mg/L) could be removed almost completely by both Aeroctere and Vermiculite (1 g/L) in 30 and 60 min, respectively at pH 7 and 24 ±1 °C. Importantly, Ca²⁺, Mg²⁺, Na⁺, HCO₃⁻, SO₄²⁻, and Cl⁻ ions had no significant effect on the adsorption of As(III) on Aeroctere and Vermiculite. The results showed that the proposed concrete-based adsorbents have the potential to remove As(III) from water.     

Electrolytic oxidation of Ce(III) in nitric acid and sulfuric acid media using a flow type cell

The electrochemical oxidation behavior of Ce(III) in nitric acid and sulfuric acid media with various concentrations and compositions were investigated by cyclic voltammetry (CV) and potentiostatic electrolysis. In nitric acid media, the peak potential separation for the redox reactions of the Ce(III)/Ce(IV) couple shifted to base side with the increasing concentration of nitric acid from 1 to 6 M. The kinetics of the Ce(III)/Ce(IV) couple is rapid in high concentration nitric acid. The formal potential is independent of both proton and nitrate concentrations while the standard rate constant increases with added protons but is independent of nitrate concentration. Constant-potential electrolysis also shows that a high proton concentration is electrochemically favorable for the electron transfer of the Ce(III)/Ce(IV) couple and for a high Ce(IV) yield in nitric acid media. The current efficiency was ca. 75% for the oxidation process of Ce(III) at 298 K. A Ce(IV) yield of ca. 80% was achieved for the electrolysis of 100 mM Ce(III) in 6 M HNO₃ solution. In sulfuric acid media, the peak potential separation for the redox reactions of the Ce(III)/Ce(IV) couple shifted to noble side with rising concentration of sulfuric acid from 0.1 to 2 M and then shifted to base side with further increase in the concentration. A Ce(IV) yield of ca. 95% was achieved for the potentiostatic electrolysis of 100 mM Ce(III) in 3 M H₂SO₄ solution.     

Voltammetric investigation of iron(III) complexes with siderophore chrysobactin in aqueous solution

Voltammetric investigations of iron(III)–chrysobactin complexes in aqueous solution at static mercury electrode, were performed. With c_Fe = (0.5–30) × 10^?7 mol dm^?3 and c_Cb = (0.5–100) × 10^?7 mol dm^?3 in pH range 6.7–10, reduction peaks with E_p ?0.64 to ?0.74 V (1) and E_p ?0.50 to ?0.62 V (2) vs. Ag/AgCl, were registered. These reduction processes were time dependent as well as solution composition (c_Fe, c_Cb and pH). Complexes are adsorbed at the mercury drop surface. Presumed stoichiometry of the detected complexes was Fe^IIICb₃ (1) and Fe^IIICb₂(OH)_x (2). Their formation/dissociation processes were described. These investigations are of biological importance as well, since provide an insight into possible reduction mechanism in the bacterial cells that use chrysobactin to acquire the iron.     

Removal of trivalent chromium(III) from solution by biosorption in cork powder

The removal of trivalent chromium from solutions using biosorption in cork powder is described. The adsorption isotherm was determined, along with the effect of different variables, such as biomass particle size, solid–liquid ratio, reaction time, metal concentration and pH, on the efficiency of chromium removal. It was concluded that the adsorption is slow and favoured by an increase in pH. Therefore, using a solid–liquid ratio of 4 g dm^?3 it is possible to reduce the chromium concentration in the solution from 10 mg dm^?3 to less than 1.5 mg dm^?3 in 2 h at 22 °C. The kinetic studies verified that the sorption of chromium by cork was described by a second‐order model. The elution results showed that 50% of the chromium bound to the cork was eluted using 0.5 mol dm^?3 H₂SO₄ and that cork maintains its binding capacity over four cycles of biosorption/elution. © 2002 Society of Chemical Industry     

Behaviour of poly(N-vinylcaprolactam) macromolecules in the presence of organic compounds in aqueous solution

Dynamic light scattering measurements have been performed for aqueous solutions of thermosensitive linear poly(N-vinylcaprolactam) (PVCa) macromolecules in the presence of NaCl and different water soluble amphiphilic organic compounds: pyrogallol (neutral amphiphilic compound), cetylpyridinium chloride (cationic surfactant) and sodium dodecylsulfate (anionic surfactant). A decrease in the macromolecular hydrodynamic diameter is observed upon addition of ionic surfactants (SDS, CPC) at low surfactant concentrations. This trend changes to an increase in the macromolecular hydrodynamic diameter at high surfactant concentration at temperatures below the temperature of polymer aggregation. This effect is in contrast with the behaviour of the systems of PVCa–non-ionic organic compounds (pyrogallol) and NaCl where we always observed the weak monotonic decrease of the hydrodynamic diameter with the increase in the concentration of organic compound, NaCl.

The behaviour of ternary systems PVCa macromolecules–ionic surfactant–pyrogallol and PVCa macromolecules–ionic surfactant–NaCl was studied. The addition of pyrogallol leads to the suppression of the intermacromolecular aggregation induced by temperature increase that is still observed at low surfactant concentrations and to the decrease of macromolecular hydrodynamic diameter. Also, the addition of NaCl to the PVCa/ionic surfactant systems results in the increase of the macromolecular hydrodynamic diameter. It is speculated that these results are due to the suppression of the cross-linking role of surfactant aggregates upon the addition of NaCl and pyrogallol.     

Iron(III) ion removal from solution through adsorption on chitosan

The potential of different forms of chitosan to adsorb iron(III) ion from a Jectofer [an iron(III)–sorbitol–citric acid complex] solution was investigated. The working solution was chosen as Jectofer, to mimic the composition of excess iron(III) as may be found in biological systems. The equilibrium studies showed that chitosan powder has the highest sorption capacity for the iron(III) ion when compared to chitosan flakes and microspheres. The amount of iron(III) adsorbed onto chitosan was found to increase with the contact time to reach equilibrium within 3 h at 37°C. A higher initial concentration of a Jectofer solution resulted in a higher amount of iron(III) adsorbed. Higher pH values, in the range 2–7, also resulted in an increase in iron(III) uptake from the solution. The data of adsorption from the Jectofer solution were found to correlate well with the Freundlich isotherm equation. In vitro adsorption experiments showed that chitosan is capable of adsorbing excess iron, measured in terms of the ferritin level, in human blood. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1185–1192, 2002; DOI 10.1002/app.10416