Studies on the fungicidal properties of some organo-tin compounds

The results of an investigation into the fungicidal properties of some bi-functional organo-tin compounds containing mono- and dithiocarbamate ligands are reported. These experiments were conducted against a number of soil and plant pathogenic fungi. While all the compounds examined proved to be powerful fungicides, differences at the concentration levels tested were not sufficiently significant to relate degree of toxicity to ligand structure. Comparison between the fungicidal activity of the di-and triphenyl-tin compounds is in agreement with earlier observations that the latter are more toxic than the former.     

Solvent Extraction Investigations on Pu(IV) and Th(IV) Complexes with Hydrophilic SO3-Ph-BTP and SO3-Ph-BTBP Ligands

ABSTRACT

Complexation of Pu(IV) and Th(IV) cations by the title ligands – hydrophilic sulfophenyl triazinyl derivatives of bis-triazinyl-pyridine and -bipyridine – was studied in solvent extraction systems containing a TODGA extractant and one of these hydrophilic ligands. Stoichiometries and stability constants of the complexes formed in an acidic (HNO₃) aqueous phase have been determined. The Pu(IV) complexes are significantly stronger than their Th(IV) analogues. Only two complexes of each metal with SO₃-Ph-BTP (1:1 and 1:2) have been detected, and only one (1:1) with SO₃-Ph-BTBP; both numbers being less than expected based on the coordination numbers of the metal ions and on the denticities of the ligands. Possible reasons of this discrepancy are discussed.     

Extraction of Uranium(VI) and Plutonium(IV) with Tetra-Alkylcarbamides

ABSTRACT

The use of tetra-alkylcarbamides as novel extractants for the separation of uranium(VI) and plutonium(IV) by solvent extraction from spent nuclear fuels is investigated in this study. Batch extraction experiments show that tetra-alkylcarbamides strongly extract U(VI) with high distribution ratios. Plutonium(IV) can be co-extracted with U(VI) at high nitric acid concentration, while high U(VI)/Pu(IV) selectivities can be reached at lower acidity. Loading capacity experiments with high uranium concentrations show that alkyl chains longer than butyl are necessary to avoid third phase formation. Nevertheless, the viscosity of uranium-loaded solvents gets too high with alkyl chains longer than pentyl. Overall, this study shows that with TPU extractant (with four pentyl chains), an efficient co-extraction of uranium and plutonium can be reached (D_U,Pu > 1) for a concentration of nitric acid higher than 4 mol?L^?1, while the partition between uranium(VI) and plutonium(IV) could be operated even at 2 mol?L^?1 nitric acid without redox chemistry.     

Kinetic,Mechanistic and Spectral Investigation of Ruthenium(III) Catalysed Oxidation of Atenolol by Alkaline Diperiodatonickelate(IV) (Stopped Flow Technique)

The kinetics of ruthenium(III) catalysed oxidation of atenolol by diperiodatonickelate(IV) (DPN) in alkaline medium at a constant ionic strength of 1.0 mol dm^–3 has been studied spectrophotometrically using a rapid kinetic accessory. The reaction exhibits 1:1 stoichiometry (DPN:atenolol). The reaction shows first order dependence on [DPN] and [Ruthenium(III)] and apparent less than unit order dependence each in atenolol and alkali concentrations. Addition of periodate has no effect on the rate of reaction. Effect of added products, ionic strength and dielectric constant of the reaction medium have been investigated. The main products were identified by IR, NMR, fluorimetry and mass spectral studies. The results suggest the formation of a complex between the atenolol and ruthenium(III) species which reacts with one mole of diperiodatonickelate(IV) species in a rate determining step, resulting in the formation of a free radical, which in a subsequent fast step yields the products. The reaction constants involved in the mechanism were evaluated. The activation parameters were computed with respect to the slow step of the mechanism and discussed.     

Synergistic Enhancement and Separation of Zirconium(IV) and Hafnium(IV) with 3-Phenyl-4-Benzoyl-5-Isoxazolone in the Presence of Crown Ethers

Abstract

3-Phenyl-4-benzoyl-5-isoxazolone (HPBI) was synthesized and examined with regard to the synergistic solvent extraction behavior of zirconium(IV) and hafnium(IV) in the presence of various crown ethers (CEs), namely, 18-crown-6 (18C6), dicylohexano-18-crown-6 (DC18C6) and benzo-15-crown-5 (B15C5) from hydrochloric acid solutions. The results demonstrated that zirconium(IV) and hafnium(IV) were synergistically extracted into chloroform with mixtures of HPBI and CEs as ZrO(PBI)₂ · CE and HfO(PBI)₂ · CE, respectively. The complexation strength follows the order DC18C6 >18C6 > B15C5. The addition of CEs not only enhances the extraction efficiency of zirconium(IV) and hafnium(IV) but also significantly, especially in the presence of B15C5, improves the selectivity (Zr/Hf = 4.73) between these metal ions as compared to HPBI alone (Zr/Hf = 2.09). On the other hand, selectivity has been moderately decreased by the addition of 18C6 or DC18C6 to the metal-chelate system.     

MNA-TBP从盐酸介质中萃取Ir(Ⅳ)

对ＭＮＡ－ＴＢＰ从盐酸介质中萃取Ｉｒ（Ⅳ）作了研究．结果表明：ＭＮＡ－ＴＢＰ对Ｉｒ（Ⅳ）萃取有协同效应．当ＭＮＡ和ＴＢＰ在正辛烷中的浓度各为０．４５ｍｏｌ／Ｌ，待萃液中ＨＣｌ总浓度为４ｍｏｌ／Ｌ，铱浓度为１７３．１３μｇ／ｍｌ，相比为１时，协萃系数Ｒ为２．３３，协萃合物的组成为（ＭＮＡＨ）＋．ＩｒＣｌ＄２－６．（ＨＴＢＰ）＋．     

Potent Chlorambucil-Platinum(IV) Prodrugs

The DNA-alkylating derivative chlorambucil was coordinated in the axial position to atypical cytotoxic, heterocyclic, and non-DNA coordinating platinum(IV) complexes of type, [Pt^IV(H_L)(A_L)(OH)₂](NO₃)₂ (where H_L is 1,10-phenanthroline, 5-methyl-1,10-phenanthroline or 5,6-dimethyl-1,10-phenanthroline, A_L is 1S,2S-diaminocyclohexane). The resultant platinum(IV)-chlorambucil prodrugs, PCLB, 5CLB, and 56CLB, were characterized using high-performance liquid chromatography, nuclear magnetic resonance, ultraviolet-visible, circular dichroism spectroscopy, and electrospray ionization mass spectrometry. The prodrugs displayed remarkable antitumor potential across multiple human cancer cell lines compared to chlorambucil, cisplatin, oxaliplatin, and carboplatin, as well as their platinum(II) precursors, PHENSS, 5MESS, and 56MESS. Notably, 56CLB was exceptionally potent in HT29 colon, Du145 prostate, MCF10A breast, MIA pancreas, H460 lung, A2780, and ADDP ovarian cell lines, with GI₅₀ values ranging between 2.7 and 21 nM. Moreover, significant production of reactive oxygen species was detected in HT29 cells after treatment with PCLB, 5CLB, and 56CLB up to 72 h compared to chlorambucil and the platinum(II) and (IV) precursors.     

腐植酸对高岭土吸附四价铀的影响

在土壤中,对放射性废物处理的安全性评估,要求评价放射性核素的迁移.PH值从4到8,腐植酸浓度从15 mg/kg到200 mg/kg条件下,腐植酸对高岭土吸附四价铀的影响试验表明,没有腐植酸的情况下,20%～40%的四价铀存在于溶液中,pH值越高,吸附作用越强.在腐植酸的存在下,随着腐植酸浓度和PH值的升高,四价铀的溶解...     

Influence of cerium (IV) ions on the mechanism of organosilane polymerization and on the improvement of its barrier properties

In this work, the effect of cerium (IV) ammonium nitrate (CAN) addition on the polymerization of bis-[triethoxysilyl]ethane (BTSE) film applied on carbon steel was studied. The electrochemical characterization of the films was carried out in 0.1 mol L⁻¹ NaCl solution by open-circuit potential measurements, anodic and cathodic polarization curves and electrochemical impedance spectroscopy (EIS). Morphological and chemical characterization were performed by atomic force microscopy (AFM), contact angle measurements, infrared-spectroscopy, nuclear magnetic resonance and thermogravimetric analysis. The results have clearly shown the improvement on the protective properties of the Ce⁴⁺ modified film as a consequence of the formation of a more uniform and densely reticulated silane film. A mechanism is proposed to explain the accelerating role of Ce⁴⁺ ions on the cross-linking of the silane layer.     

Synthesis and characterization of the first poly(imidazolyl)borate organotin(IV) complex exhibiting a polymeric chain structure

The reaction between SnR_nX_4−n (R=Me, Ph or cy; n=2 or 3) acceptors and sodium tetrakis(imidazol-1-yl)borate, Na[B(im)₄], yields {[B(im)₄]R_nSnCl_4−n−1} compounds. The X-ray crystal structure of [μ-(im)₂B(im)₂SnMe₃] is the first example of a polymeric derivative containing the [B(im)₄]⁻ ligand coordinated in bridging fashion.     

Separation of rhodium(III) and iridium(IV) chlorido complexes using polymer microspheres functionalized with quaternary diammonium groups

Merrifield resin functionalized with different quaternary diammonium groups derived from ethylenediamine (EDA), tetramethylenediamine (TMDA), hexamethylenediamine (HMDA), 1,8-diaminooctane (OMDA), 1,10-diaminodecane (DMDA) and 1,12-diaminododecane (DDMDA) were investigated for the separation of [RhCl₅(H₂O)]^2? and [IrCl₆]^2?. Selective loading of [IrCl₆]^2? in 6 M HCl medium onto the column was achieved in the presence of [RhCl₅(H₂O)]^2? by the synthesized sorbents. The iridium loading capacities were 3.80, 6.49, 13.07, 19.29, 27.09 and 4.36 mg/g for EDA, TMDA, HMDA, OMDA, DMDA and DDMDA-functionalized microspheres, respectively. The materials showed great potential for application in separating rhodium and iridium from aqueous HCl solutions.     

Structural and Catalytic Studies of a Trimethyltin Vanadate Coordination Polymer

The organotin vanadate [Me₃SnVO₃] (1) has been prepared and characterised in the solid state by powder X-ray diffraction (XRD), thermogravimetric analysis, multinuclear magic-angle spinning (MAS) NMR, IR and Raman spectroscopy. The phase purity and structure of microcrystalline 1 were confirmed by carrying out a full Rietveld structural refinement at ambient temperature and from conventional powder XRD. ⁵¹V and ¹¹⁹Sn MAS NMR data for compound 1 were in agreement with the predicted structure, showing two equally-abundant, nonequivalent Me₃Sn groups and two equally-abundant, nonequivalent vanadium atoms. The compound was applied as a catalyst for the liquid-phase epoxidation of olefins at 55 °C using tert-butyl hydroperoxide (tBuOOH) as the oxidant. The reaction rate for the different substrates followed the order cis-cyclooctene > (R)-(+)-limonene ≅ trans-2-octene > cyclododecene > styrene > 1-octene; the corresponding epoxides were the only observed products. Leaching tests indicated that the catalytic epoxidation of cyclooctene was mainly heterogeneous in nature. This paper is dedicated to Professor Ian Manners and his scientific accomplishments.     

Synthesis, Characterization and Crystal Structure of a Novel One-Dimensional Supramolecular Dimethyltin (IV) Compound

A novel one-dimensional (1D) supramolecular dimethyltin compound of (Me₂SnO)₂(Me₂SnOCH₃)(O₂CCH₂SC₄H₃N₂-2,6)[Me₂Sn(O₂CCH₂SC₄H₃N₂-2,6)₂]·CH₃OH was prepared by the reaction of (CH₃)₂SnCl₂ with (2-pyrimidylthio)acetic acid with CH₃ONa as a base. The title compound contained four different tin atom environments. Among them, Sn(1) and Sn(2) were both five-coordinate with distorted trigonal bipyramidal geometries, Sn(3) was six-coordinate with a distorted octahedral geometry and Sn(4) was seven-coordinate with pentagonal bipyramidal geometry. Meanwhile, the compound was stabilized in a 1D infinite chain by intermolecular Sn–O bonds. An erratum to this article can be found at     

Selective Extraction and Separation of Ce (IV) and Th (IV) from RE(III) in Sulfate Medium using Di(2-ethylhexyl)-N-heptylaminomethylphosphonate

The extraction and separation of Ce(IV) and Th(IV) from trivalent rare earths (RE, including scandium) in sulfate medium using di(2-ethylhexyl)-N-heptylaminomethylphosphonate (DEHAMP, L) were studied. The effects of H₂SO₄ concentration, extractant concentration, and temperature on the metal extraction were investigated systematically. It was found that the extraction of metal ions by DEHAMP decreases in the following order: Ce(IV) > Th(IV) > Sc(III) > other RE(III). A possible extraction mechanism was proposed and the extracted complexes as Ce(SO₄)₂·2L and Th(HSO₄)₂SO₄·L were determined by the slope analysis method. Thermodynamic parameters (ΔH, ΔG, and ΔS) were calculated. The extraction reactions of Ce(IV) and Th(IV) were each exothermic processes. The loaded Ce(IV) and Th(IV) can be stripped efficiently by 3% H₂O₂ and 4 mol/L HCl, respectively. The extraction capacity of 0.63 mol/L DEHAMP is 30.0 g/L CeO₂ and 24.4 g/L ThO₂, respectively. Furthermore, a solvent extraction process to selectively extract and recover cerium and thorium from bastnaesite leaching was proposed, by which the purities of cerium and thorium products reached 97.2% and 96.5% with a yield of 85.4% and 98.8%, respectively.     

Adsorption of Ce(IV) Ions from Aqueous Solution by Silica Aerogels

The adsorption process of Ce(IV) ions from aqueous solution by the silica aerogels was studied. The silica aerogels with hydrophobicity were prepared by the sol-gel process, supercritical drying, and heat treatment. The SEM image and nitrogen adsorption-desorption isotherm show that the heat-treated silica aerogel was a co-continuous porous structure with high BET surface area and narrow pore size distribution. The adsorption of Ce(IV) ions onto the silica aerogels was found to be fitted well by pseudo-second-order kinetics and Langmuir isotherm model. The activation energy for Ce(IV) adsorption onto silica aerogels could be calculated to be about 17.88 kJ/mol, which implied that the attractive forces of adsorption were weak electrostatic forces accompanying most ion-exchange reactions. The thermodynamic parameters showed that the adsorption process was spontaneous and endothermic.     

Extraction and separation of Pt(IV)/Rh(III) from acidic chloride solutions using Aliquat 336

Extraction and separation of Pt(IV)/Rh(III) from chloride solutions using Aliquat 336 (Quaternary ammonium salt made by the methylation of mixed tri octyl/decyl amine) diluted in kerosene as an extractant/synergist alone and mixed with organophosphorous extractants as synergists/extractants were carried out from an aqueous feed containing 0.0005 mol L⁻¹ Pt(IV)/Rh(III).Variation of hydrochloric acid concentration of aqueous phase from 0.005 to 10.0 mol L⁻¹ increased the percentage extraction of platinum up to 5.0 mol L⁻¹ there after it decreases. Whereas in the case of rhodium, from 0.005 to 1.0 mol L⁻¹ acid range the percentage extraction was decreased from 1.0 to 10.0 mol L⁻¹ acid range is favorable for extraction. Platinum(IV)/rhodium(III) separation factor of 279.2 was obtained at 1.0 mol L⁻¹ HCl concentration with 0.005 mol L⁻¹ Aliquat 336 and separation factor of 612.3 was obtained at 3.0 mol L⁻¹ HCl concentration with 0.01 mol L⁻¹ Aliquat 336. The present study optimized the various experimental parameters like phase contact time, effect of extractant, salts, temperature, loading capacity of extractant, stripping studies with various mineral acids/bases, recycling and reusing capacity of extractant up to ten cycles.     

The Separation of Rhodium and Iridium. II. Chloridation and Chlorination of Iridium(III) and (IV)

Abstract

The chloridation of iridium(III) chloro aquo complexes was studied at different aqueous HCl concentrations and temperatures to determine the optimum conditions which upon chlorination will lead to the most convenient method to produce an aqueous solution which only contains the [IrCl₆]^2? species required for very efficient separation of iridium from rhodium by separating agents like quaternary ammonium species. The interdependency of the two processes of chloridation and chlorination is indicated.     

Synthesis, ion exchange properties and applications of tin(IV) antimonoarsenate

Crystalline (c-SnSbAs) and amorphous (a-SnSbAs) samples of tin(IV) antimonoarsenate were prepared at different pH values from 0 to 5. Crystalline and amorphous samples, prepared at pH 1 having ion exchange capacities of 1.00 meq/g and 0.90 meq/g respectively, were selected for further studies. The materials show high thermal and chemical stability. Distribution coefficients (K_d values) for 22 metal ions have been determined in demineralised water. Structural studies based on IR, XRD, TGA, DTA are discussed. Some quantitative binary separations such as Mg²⁺–Mn²⁺, Cd²⁺–Mn²⁺, Ba²⁺–Mn²⁺ and Ni²⁺–Cu²⁺ were achieved on a-SnSbAs and ion selective electrodes prepared from c-SnSbAs are reported.     

Sequential Separation and Trace Enrichment of Thorium(IV) and Uranium(VI) on Chelating Resin Amberlite XAD-2-ortho-vanillinthiosemicarbazone (o-VTSC)

ABSTRACT

Polystyrenc-divinylbenzene-based Amberlite XAD-2 was funetionalized with ortho-vanillinthiosemicarbazone and its analytical properties were investigated. The resin was used successfully for the separation and preconcentration of thorium(IV) and uranium(VI) ions prior to their determination by spectrophotometry and by ICAP-AES and GF-AAS, respectively. The influence of several ions as interferents is discussed. The resin exhibits good chemical stability, reuseability, and a faster rate of equilibration for their determination. The proposed method has been applied to sequential chromatographic separation of thorium(IV) and uranium(VI) on river water samples with good analytical reliability such as recovery of 97–98%, relative standard deviation of 2–3%, and a detection limit of 100 ng-mL^-1. The present method is also used for their determination in monazite sand and some standard geological materials.     

Equilibrium studies of the extraction of zirconium(IV) from sulfuric acid solutions with Di(2-ethylhexyl)phosphoric acid

Equilibrium studies were made at 25°C in the extraction of zirconium(IV) from sulfuric acid solutions with di(2-ethylhexyl)phosphoric acid (D2EHPA, HR) dissolved in kerosene. The reaction stoichiometry was numerically determined and the compositions of the extracted species were found to be ZrR₄ and ZrR₄(HR) at low loading ratios of D2EHPA (α < 0.09), but became ZrR₄ and ZrR₄(HR)₃ at relatively higher loading ratios (0.10 < α < 0.32). The equilibrium constants for the formation of these species were also obtained. Furthermore, numerical treatment of the experimental data excluded the existence of polynuclear complexes under the conditions studied (α < 0.32).