Application of capillary electrophoresis technique for the enantioseparation of bioactive ferrocene-based compounds versus DFT calculated data

Herein, a series of bioactive ferrocene-modified N-heterocycles with alkyl linkers was prepared in good to quantitative yields starting from easy accessible ferrocene alcohols and heterocycles under acidic or neutral (for imidazole) conditions in racemic forms. The analytical resolution of a number of bioactive racemic ferrocene azoles 1-6 (where azole = imidazole, pyrazole, and benzotriazole derivatives) into enantiomers was first carried out by CE using sulfobuthylether-β-CD (captisol) as a chiral selector. The analytical approaches to highly enantiomeric-enriched ferrocene derivatives are based on the formation of their inclusion complexes. The best chiral separation was achieved using zone CE in a quartz capillary. The ACE was used to evaluate the stability constants of captisol complexes with enantiomeric forms of two ferrocene derivatives 1, FcCHMe-imidazole, and 6, FcCHMe-benzotriazole. The optimal conditions for the resolution of the studied (R, S)-ferrocene compounds 1, 2, and 6 were predicted on the basis of the performed quantum chemical calculations and then implemented by the electrophoretic method. A high correlation between density functional theory calculation results and experimental electrophoresis data were obtained. Successful enantioseparation of racemic mixtures is of great importance for the characterization and further applications of drug candidates in enantiopure forms and in the development of clinical treatment. The advantages of the CE procedure make it possible to have important practical value and significance for determining the purity and enantiomeric excess of other ferrocene-containing compounds.

Potentials and challenges of phosphorus recovery as vivianite from wastewater: A review

Due to the shortage of phosphorus resources and the limitations of existing phosphorus recovery methods, phosphorus recovery in the form of vivianite has attracted considerable attention with its natural ubiquity, easy accessibility and foreseeable economic value. This review systematically summarizes the chemistry of vivianite, including the characteristics, formation process and influencing factors of the material. Additionally, the potential of phosphorus recovery as vivianite from wastewater has also been comprehensively examined from the prospects of economic value and engineering feasibility. In general, this method is theoretically and practically feasible, and brings some extra benefits in WWTPs. However, the insufficient understanding on vivianite recovery in wastewater/sludge decelerate the development and exploration of such advanced approach. Further researches and cross-field supports would facilitate the improvement of this technique in the future.

Electrochemically induced oxidative precipitation of Fe(II) for As(III) oxidation and removal in synthetic groundwater

Mobilization of Arsenic in groundwater is primarily induced by reductive dissolution of As-rich Fe(III) oxyhydroxides under anoxic conditions. Creating a well-controlled artificial environment that favors oxidative precipitation of Fe(II) and subsequent oxidation and uptake of aqueous As can serve as a remediation strategy. We reported a proof of concept study of a novel iron-based dual anode system for As(III) oxidation and removal in synthetic groundwater. An iron anode was used to produce Fe(II) under iron-deficient conditions, and another inert anode was used to generate O2 for oxidative precipitation of Fe(II). For 30 min's treatment, 6.67 μM (500 μg/L) of As(III) was completely oxidized and removed from the solution during the oxidative precipitation process when a total current of 60 mA was equally partitioned between the two anodes. The current on the inert anode determined the rate of O2 generation and was linearly related to the rates of Fe(II) oxidation and of As oxidation and removal, suggesting that the process could be manipulated electrochemically. The composition of Fe precipitates transformed from carbonate green rust to amorphous iron oxyhydroxide as the inert anode current increased. A conceptual model was proposed for the in situ application of the electrochemically induced oxidative precipitation process for As(III) remediation.

A novel electrochemical process for the recovery and recycling of ferric chloride from precipitation sludge

During wastewater treatment and drinking water production, significant amounts of ferric sludge (comprising ferric oxy-hydroxides and FePO4) are generated that require disposal. This practice has a major impact on the overall treatment cost as a result of both chemical addition and the disposal of the generated chemical sludge. Iron sulfide (FeS) precipitation via sulfide addition to ferric phosphate (FePO4) sludge has been proven as an effective process for phosphate recovery. In turn, iron and sulfide could potentially be recovered from the FeS sludge, and recycled back to the process. In this work, a novel process was investigated at lab scale for the recovery of soluble iron and sulfide from FeS sludge. Soluble iron is regenerated electrochemically at a graphite anode, while sulfide is recovered at the cathode of the same electrochemical cell. Up to 60 ± 18% soluble Fe and 46 ± 11% sulfide were recovered on graphite granules for up-stream reuse. Peak current densities of 9.5 ± 4.2 A m(-2) and minimum power requirements of 2.4 ± 0.5 kWh kg Fe(-1) were reached with real full strength FeS suspensions. Multiple consecutive runs of the electrochemical process were performed, leading to the successful demonstration of an integrated process, comprising FeS formation/separation and ferric/sulfide electrochemical regeneration.

Ferrous iron removal by limestone and crushed concrete in dynamic flow columns

In-situ passive reactive barriers containing carbonate minerals show potential for dissolved iron removal from groundwater at landfill sites. The removal of Fe(II) from synthetic groundwater using limestone and crushed concrete (7-10 mm) was evaluated using dynamic flow columns. Solutions of 50 mg/L Fe(II) were passed through duplicate columns of limestone and concrete until breakthrough (250-300 days); water quality was evaluated at distinct column depths throughout the study. Each material was successful in reducing the concentration of Fe(II), with both achieving an average of greater than 99.4% iron removal (<0.3 mg/L effluent concentration) over 288 and 216 pore volumes, resulting in effective removal capacities of 4.06 and 3.80 g Fe/kg reactive material for limestone and crushed concrete, respectively. These values are less than removal capacities achieved from a sequencing batch test (32.9 and 27.9 g Fe/kg limestone and crushed concrete, respectively), a possible result of preferential flow pathways, shorter equilibration time, and formation of surface films on the reactive materials in the columns.

Sediment porewater extraction and analysis combining filter tube samplers and capillary electrophoresis

Careful extraction and analysis of porewater from sediment cores are critical for the investigation of small-scale biogeochemical processes. Firstly, small sample volumes and high spatial resolution are required. Secondly, several chemical species in the anaerobic porewater are sensitive to oxidation when brought in contact with ambient air. Here we present the combination of a special sampling technique and an analytical method for the porewater extraction of a varved sediment core from Lake Baldegg in central Switzerland, using MicroRhizon samplers and a portable capillary electrophoresis (CE) instrument. MicroRhizon filter tubes of 1 mm diameter and 20 mm length are suitable for fast retrieval of particle-free porewater samples directly from the sediment core. Since the time-span between sampling and analysis is less than 20 seconds, oxygen-sensitive Fe(ii) can be analyzed in one go together with Na(+), K(+), Ca(2+), Mg(2+), NH4(+), and Mn(ii) without splitting, acidification or dilution of the sample. The major inorganic cations and anions of the sediment porewater can be determined in less than 15 minutes. Detection limits are in the sub-micromolar concentration range. The capillary electrophoresis instrument used in this study requires sample volumes of only 20 μL. These remarkable small sample volumes allow the minimization of disturbance of the sediment cores and a high spatial resolution of the sediment profile, even in sediments with low water content. The equipment is inexpensive, easy to handle, fully portable and therefore suitable for environmental on-site applications.

Removal of FePO4 and Fe3(PO4)2 crystals on the surface of passive fillers in Fe0/GAC reactor using the acclimated bacteria

As past studies presented, there is obvious defect that the fillers in the Fe(0)/GAC reactor begin to be passive after about 60 d continuous running, although the complicated, toxic and refractory ABS resin wastewater can be pretreated efficiently by the Fe(0)/GAC reactor. During the process, the Fe(3)(PO(4))(2) and FePO(4) crystals with high density in the passive film are formed by the reaction between PO(4)(3-) and Fe(2+)/Fe(3+). Meanwhile, they obstruct the formation of macroscopic galvanic cells between Fe(0) and GAC, which will lower the wastewater treatment efficiency of Fe(0)/GAC reactor. In this study, in order to remove the Fe(3)(PO(4))(2) and FePO(4) crystals on the surface of the passive fillers, the bacteria were acclimated in the passive Fe(0)/GAC reactor. According to the results, it can be concluded that the Fe(3)(PO(4))(2) and FePO(4) crystals with high density in the passive film could be decomposed or removed by the joint action between the typical propionic acid type fermentation bacteria and sulfate reducing bacteria (SRB), whereas the PO(4)(3-) ions from the decomposition of the Fe(3)(PO(4))(2) and FePO(4) crystals were released into aqueous solution which would be discharged from the passive Fe(0)/GAC reactor. Furthermore, the remained FeS and sulfur (S) in the passive film also can be decomposed or removed easily by the oxidation of the sulfur-oxidizing bacteria. This study provides some theoretical references for the further study of a cost-effective bio-regeneration technology to solve the passive problems of the fillers in the zero-valent iron (ZVI) or Fe(0)/GAC reactor.

Optimization of hydrous ferrous sulfate dehydration by microwave heating using response surface methodology

The work relates to assessing the ability of the microwave for dehydration of large amount of waste hydrous ferrous sulfate generated from the titanium pigment process industry. The popular process optimization tool of response surface methodology with central composite design was adopted to estimate the effect of dehydration. The process variables were chosen to be power input, duration of heating and the bed thickness, while the response variable being the weight loss. An increase in all the three process variables were found to significantly increase the weight loss, while the effect of interaction among the parameters were found to be insignificant. The optimized process conditions that contribute to the maximum weight loss were identified to be a power input of 960 W, duration of heating of 14 min and bed thickness of 5 cm, resulting in a weight loss of 31.44%. The validity of the optimization process was tested with the repeat runs at optimized conditions.

Removal and recovery of lead (II) ions from contaminated licorice extracts using oxidized multi-walled carbon nanotubes

A column with oxidized multi-walled carbon nanotubes (MWNTs) has been studied as a sorbent for removing and accumulating lead (II) from contaminated Licorice extracts. Under optimized situation, the adsorption capacity of lead (II) on oxidized MWNTs was 17 mg g(-1) at pH 7.0, and the lead (II) was eluted with 10 ml of 1% hydrochloric acid. Additionally, the effects of adsorptive parameters, including pH of the solution, sample volume, flow rates of the sample, matrix ions, and eluent type were investigated for optimization of the presented procedure. A fluorescence spectrophotometer was employed to determine the contents of lead (II). High-performance liquid chromatography (HPLC) was developed for the quantitative determination of main constituents of Licorice extracts. Oxidized MWNT cartridges were used to remove lead ions from contaminated Licorice extracts, high adsorption capacity, adsorption reversibility of lead (II), and low loss of major constituents. The results suggested that the oxidized MWNT column has the potential to remove heavy metal ions from herbal extracts.

A comparative study on two extraction procedures in speciation of iron in municipal solid waste

Two extraction reagents, hydrochloric acid (HCl) and acid ammonium oxalate solution (Tamm's reagent), were used to evaluate the redox state of iron in municipal solid waste (MSW) with different deposit ages. Orthogonal experiments were conducted to optimize the extraction conditions for extractable iron speciation (ferric and ferrous) in MSW. The optimal extraction conditions for HCl were determined as follows: the liquid-to-solid ratio was set at 100, and then the samples were extracted at the shaking speed of 200 rpm at 35 degrees C for 60 min by 1.00 M HCl. For Tamm's reagent, the optimal extraction conditions were extracted at the shaking speed of 175 rpm at 30 degrees C for 12 h with the same liquid-to-solid ratio. However, Tamm's reagent extraction is much more laborious and time-consuming. Thus the HC1 extraction might be a better choice for the evaluation of the redox state of iron in MSW. The results also showed that the yield of extractable iron increased with deposited age. About 60-83% of extractable iron was presented as ferrous in the MSW deposited for 1-8 years. This study supplied a tool for investigating the role of iron on the fate of pollutants in the landfill.

On the validity of specific rate constants (kSA) in Fe0/H2O systems

The validity of the specific reaction rate constants (k(SA)) in modelling contaminant removal in Fe(0)/H(2)O systems is questioned. It is shown that the current k(SA)-model does not consider the large reactive surface area provided by the in-situ formed oxide film, and thus the adsorptive interactions between contaminants and film materials. Furthermore, neither the dynamic nature of film formation nor the fact that the Fe(0) surface is shielded by the film is considered. Suggestions are made how the k(SA)-model could be further developed to meet its original goal.

Iron-monosulfide oxidation in natural sediments: resolving microbially mediated S transformations using XANES, electron microscopy, and selective extractions

Iron-monosulfide oxidation and associated S transformations in a natural sediment were examined by combining selective extractions, electron microscopy and S K-edge X-ray absorption near-edge structure (XANES) spectroscopy, The sediment examined in this study was collected from a waterway receiving acid-sulfate soil drainage. It contained a high acid-volatile sulfide content (1031 micromol g(-1)), reflecting an abundance of iron-monosulfide. The iron-monosulfide speciation in the initial sediment sample was dominated by nanocrystalline mackinawite (tetragonal FeS). At near-neutral pH and an 02 partial pressure of approximately 0.2 atm, the mackinawite was found to oxidize rapidly, with a half-time of 29 +/- 2 min. This oxidation rate did not differ significantly (P < 0.05) between abiotic versus biotic conditions, demonstrating that oxidation of nanocrystalline mackinawite was not microbially mediated. The extraction results suggested that elemental S (S8(0)) was a key intermediate S oxidation product Transmission electron microscopy showed the S8(0) to be amorphous nanoglobules, 100-200 nm in diameter. The quantitative importance of S8(0) was confirmed by linear combination XANES spectroscopy, after accounting for the inherent effect of the nanoscale S8(0) particle-size on the corresponding XANES spectrum. Both the selective extraction and XANES data showed that oxidation of S8(0) to SO4(2-) was mediated by microbial activity. In addition to directly revealing important S transformations, the XANES results support the accuracy of the selective extraction scheme employed here.

Enhanced heavy metals removal without phosphorus loss from anaerobically digested sewage sludge

Heavy metals removal without phosphorus loss from anaerobically digested sewage sludge was investigated by conducting batch experiments using hydrogen peroxide and/or iron sulphate under acidified conditions at pH 3. The addition of hydrogen peroxide to the sludge improved the elution efficiencies of As, Cd, Cu and Zn with phosphorus loss from the sludge. The optimum initial concentrations of hydrogen peroxide were. Respectively. 0.1% for As, Cd, Mn and Zn and 0.5% for Cu and Ni. The combined process of 0.1% hydrogen peroxide and 1 g Fe/L ferric sulphate enhanced the initial elution rate of Cu and Cr compared to the addition of either ferric sulphate or hydrogen peroxide, indicating that oxidants stronger than hydrogen peroxide were produced in the sludge. Furthermore, the combined process immobilised phosphorus in the sludge due to co-precipitation with ferric hydroxide or precipitation as ferric phosphate. It was concluded that there is a possibility that the combined process could remove heavy metals effectively without phosphorus loss from anaerobically digested sewage sludge.

Separation and determination of metallocyanide complexes of Fe(II), Ni(II) and Co(III) by ion-interaction chromatography with membrane suppressed conductivity detection applied to analysis of oil refinery streams (sour water)

A separation and determination method for the analysis of cyanometallic complexes of Fe(II), Ni(II) and Co(III) was developed to be applied to the analysis of petroleum refinery streams (sour water). Ion-interaction chromatography was used employing an analytical column IonPac NS1 10 microm and a chromatographic system ICS 2500 equipped with a membrane conductivity suppression ASRS ultra 4mm, both supplied by Dionex Corporation. The mobile phase was composed of 2 mmol l(-1) TBAOH, 1 mmol l(-1) Na(2)CO(3), 0.1 mol l(-1) NaCN and ACN (77:23, v/v), flowing at 0.7 ml min(-1). At the optimized conditions, detection limits estimated by the calibration curve parameters and relative standard deviation were: 0.002 mg CNl(-1) and 3.1% for Fe(CN)(6)(4-); 0.003 mg CNl(-1) and 2.5% for Ni(CN)(4)(2-) and 0.003 mg CNl(-1) and 2.8% for Co(CN)(6)(3-). Sour water samples without any pretreatment (except membrane filtration) from a petroleum refinery in Brazil were analyzed successfully by external calibration method.

Removal of iron and manganese using biological roughing up flow filtration technology

The removal of iron and manganese from groundwater using biological treatment methods is almost unknown in Latin America. Biological systems used in Europe are based on the process of double rapid biofiltration during which dissolved oxygen and pH need to be strictly controlled in order to limit abiotic iron oxidation. The performance of roughing filter technology in a biological treatment process for the removal of iron and manganese, without the use of chemical agents and under natural pH conditions was studied. Two pilot plants, using two different natural groundwaters, were operated with the following treatment line: aeration, up flow roughing filtration and final filtration (either slow or rapid). Iron and manganese removal efficiencies were found to be between 85% and 95%. The high solid retention capability of the roughing filter means that it is possible to remove iron and manganese simultaneously by biotic and abiotic mechanisms. This system combines simple, low-cost operation and maintenance with high iron and manganese removal efficiencies, thus constituting a technology which is particularly suited to small waterworks.

Preparation and characterization of the native iron(II)-containing DNA repair AlkB protein directly from Escherichia coli

The Escherichia coli AlkB protein was recently found to repair cytotoxic DNA lesions 1-methyladenine and 3-methylcytosine by using a novel iron-catalyzed oxidative demethylation mechanism. This protein belongs to a family of 2-ketoglutarate-Fe(II)-dependent dioxygenase proteins that utilize iron and 2-ketoglutarate to activate dioxygen for oxidation reactions. We report here the overexpression and isolation of the native Fe(II)-AlkB with a bound cofactor, 2-ketoglutarate, directly from E. coli. UV-vis measurements showed an absorption peak at 560 nm, which is characteristic of a bidentate 2-ketoglutarate bound to an iron(II) ion. Addition of excess amounts of single-stranded DNA to this isolated Fe(II)-AlkB protein caused a 9 nm shift of the 560 nm band to a higher energy, indicating a DNA-binding-induced geometry change of the active site. X-ray absorption spectra of the active site iron(II) in AlkB suggest a five-coordinate iron(II) center in the protein itself and a centrosymmetric six-coordinate iron(II) site upon addition of single-stranded DNA. This geometry change may play important roles in the DNA damage-searching and damage-repair functions of AlkB. These results provide direct evidence for DNA binding to AlkB which modulates the active site iron(II) geometry. The isolation of the native Fe(II)-AlkB also allows for further investigation of the iron(II) center and detailed mechanistic studies of the dioxygen-activation and damage-repair reactions performed by AlkB.

Iron Coordination Chemistry of Phenylpyruvate: An Unexpected κ3-Bridging Mode That Leads to Oxidative Cleavage of the C2−C3 Bond

One mononuclear iron(II)-phenylpyruvate complex [Tp(Ph2)Fe(II)(PPH)] (1) of the tridentate face-capping Tp(Ph2) ligand and two dinuclear iron(II)-phenylpyruvate enolate complexes [(6-Me3-TPA)2Fe(II)2(PP)]2+ (2) and [(6-Me3-TPA)2Fe(II)2(2-NO2-PP)]2+ (3) of the tetradentate 6-Me3-TPA ligand are reported to demonstrate two different binding modes of phenylpyruvate to the iron(II) centers. Phenylpyruvate binds in a kappa2-(O,O) manner to the mononuclear Fe(II)(Tp(Ph2)) center of 1 but bridges in a kappa3-(O,O,O) fashion to the two Fe(II)(6-Me3-TPA) centers of 2 and 3. Mononuclear complex 1 reacts with O2 to undergo oxidative decarboxylation and ortho-hydroxylation of one of the aromatic rings of the Tp(Ph2) ligand. In contrast, dinuclear complexes 2 and 3 react with O2 to undergo oxidative cleavage of the C2-C3 bond of phenylpyruvate.

Reactions ofmeso-Hydroxyhemes with Carbon Monoxide and Reducing Agents in Search of the Elusive Species Responsible for theg= 2.006 Resonance of Carbon Monoxide-Treated Heme Oxygenase. Isolation of Diamagnetic Iron(II) Complexes of Octaethyl-meso-hydroxyporphyrin

To examine possible models for the g = 2.006 resonance seen when the hydroxylated heme-heme oxygenase complex in the Fe(III) state is treated with CO, the reactivities of CO and reducing agents with (py)(2)Fe(III)(OEPO) and [Fe(III)(OEPO)](2) (OEPO is the trianion of octaethyl-meso-hydroxyporphyrin) have been examined. A pyridine solution of (py)(2)Fe(III)(OEPO) reacts in a matter of minutes with zinc amalgam (or with hydrazine) under an atmosphere of dioxygen-free dinitrogen to produce bright-red (py)(2)Fe(II)(OEPOH).2py.0.33H(2)O, which has been isolated in crystalline form. The (1)H NMR spectrum of (py)(2)Fe(II)(OEPOH) in a pyridine-d(5) solution is indicative of the presence of a diamagnetic compound, and no EPR resonance was observed for this compound. Treatment of a solution of (py)(2)Fe(II)(OEPOH) in pyridine-d(5) with carbon monoxide produces spectral changes after a 30 s exposure that are indicative of the formation of diamagnetic (OC)(py)Fe(II)(OEPOH). Treatment of a green pyridine solution of (py)(2)Fe(III)(OEPO) with carbon monoxide reveals a slow color change to deep red over a 16 h period. Although a resonance at g = 2.006 was observed in the EPR spectrum of the sample during the reaction, the isolated product is EPR silent. The spectroscopic features of the final solution are identical to those of a solution formed by treating (py)(2)Fe(II)(OEPOH) with carbon monoxide. Addition of hydrazine to solutions of (OC)(py)Fe(II)(OEPOH) produces red, diamagnetic (OC)(N(2)H(4))Fe(II)(OEPOH).py in crystalline form. The X-ray crystal structures of (py)(2)Fe(II)(OEPOH).2py.0.33H(2)O and (OC)(N(2)H(4))Fe(II)(OEPOH).py have been determined. Solutions of diamagnetic (OC)(N(2)H(4))Fe(II)(OEPOH).py and (OC)(py)Fe(II)(OEPOH) are extremely air sensitive and are immediately converted in a pyridine solution into paramagnetic (py)(2)Fe(III)(OEPO) in the presence of dioxygen.

On-column complexation capillary electrophoretic separation of Fe2+ and Fe3+ using 2,6-pyridinedicarboxylic acid coupled with large-volume sample stacking

On-column complexation of Fe2+ and Fe3+ with 2,6-pyridinedicarboxylic acid (2,6-PDCA) formed anionic complexes, which were then separated by capillary zone electrophoresis with direct UV detection at 214 nm. To achieve reasonable separation selectivity and on-column complexation, the conditions such as pH, the concentration of 2,6-PCDA and the EOF modifiers in the electrolyte were examined. The electrolyte contained 5.0 mM 2,6-PDCA, 0.25 mM tetradecyltrimethlammonium bromide (TTAB) and 5% (v/v) acetonitrile at pH 4.0 was optimised for on-column complexation and the separation of Fe[PCDA]2(2-) and Fe[PCDA]2(-). To enhance the detection sensitivity, large-volume sample stacking (LVSS) was used for the on-line preconcentration of Fe[PCDA]2(2-) and Fe[PCDA]2(-). Under the optimised conditions, satisfactory working ranges (0.5-50 microM), lower detection limits (less than 0.1 microM) and good repeatability of the peak areas (R.S.D.: 5.2-7.8%, n = 5) was achieved using LVSS (300 s). With LVSS, the detection sensitivity was enhanced more than 50-fold compared to conventional hydrodynamic injection. The proposed method was used successfully for the determination of Fe2+ and Fe3+ in water samples.

Fast liquid chromatography-electrochemistry-mass spectrometry of ferrocenecarboxylic acid esters

Rapid liquid chromatographic separations of ferrocenecarboxylic esters of various alcohols and phenols have been achieved on reversed-phase columns of 20 mm length. After separation, the ferrocene derivatives are oxidized electrochemically under formation of the charged ferrocinium species, which are easily detected by mass spectrometry using an atmospheric pressure chemical ionization source operated in the heated nebulizer mode. While a series of nine phenol derivatives was separated within less than 1.5 min, six alcohol derivatives eluted within 1 min. Limits of detection using a single quadrupole mass analyzer ranged from 60 to 190 nmol/l. Additional work was directed on the use of a graphite in-line filter instead of a silica-based reversed-phase column to achieve the separation.

Separation of planar chiral ferrocene derivatives on beta-cyclodextrin-based polymer supports prepared via ring-opening metathesis graft-polymerization

A series of beta-cyclodextrin (beta-CD) based chiral stationary phases (CSPs) were synthesized by ring-opening metathesis graft polymerization of various norborn-2-ene (NBE) substituted CDs. Chiral selectors based on endo/exo-6-O-(norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD, tris(endo/exo-6-O-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD, tetrakis(endolexo-6-0-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD, hexakis(endo/exo-6-O-norborn-2-ene-5-ylmethoxymethylsilyl)-beta-CD and tetrakis(endo-6-O-norborn-2-ene-5-carboxyl)-beta-CD were grafted onto Nucleosil 300-5 using well-established grafting procedures. CSPs were investigated for their separation capabilities for a series of the planar chiral ferrocene derivatives, rac-ferroceno[2,3a]inden-1-one (1a, 1b), rac-6-(3-hydroxy-3-methylbut-1-yn-1-yl)ferroceno[2,3a]inden-1-one (2a, 2b), rac-ferrocene[2,3a]indene (3a, 3b), rac-endo 1-methoxy-1-allylferroceno[2,3a]indene (4a, 4b) and rac-1,4-dihydroxybutylferrocene (5a, 5b). Compounds la, lb and 2a, 2b bearing a carbonyl group were successfully separated on these CSPs, while compounds 3-5 do not undergo enantioselective interaction under the conditions applied. General aspects of separation as well as mechanistic implementations are discussed.

Magnetic and structural properties of electrochemically self-assembled Fe1-xCox nanowires

Fe1-xCox (0 < or = x < or = 1) nanowires have been self-assembled by electrodeposition in porous alumina films. The crystal structure is bee at the Fe end. With increased addition of Co, the crystal structure remains bcc until about 67% addition of Co. At the Co end, the structure is a mixture of hcp and fcc. Magnetic studies show very high coercivities for the Fe-Co alloys in the bcc phase. For Fe0.67Co0.33 nanowires of diameter 9 nm, the coercivity is about 2900 Oe, whereas for Fe0.33Co0.67 nanowires, it is about 2850 Oe. Temperature and size dependence of magnetic properties show no indication of superparamagnetic effects down to wire diameters of 9 nm.

Ferroverdins, inhibitors of cholesteryl ester transfer protein produced by Streptomyces sp. WK-5344. I. Production, isolation and biological properties

Streptomyces sp. WK-5344, a soil isolate, was found to produce structurally related inhibitors of cholesteryl ester transfer protein (CETP). New active compounds, designated ferroverdins B and C, were isolated along with known ferroverdin A from the fermentation broth by solvent extraction, ODS column chromatography and silica gel column chromatography. All ferroverdins showed a dose-dependent inhibitory activity against human CETP. The IC50 values were 21, 0.62 and 2.2 microM for ferroverdins A, B and C, respectively, indicating that ferroverdin B is one of the most potent CETP inhibitors of microbial origin.

[The determination of ferroceron in the practice of forensic chemical expertise]

Valov's method followed by extraction of the acid form of ferroceron with ether is recommended for isolation of ferroceron from cadaveric material in forensic chemical practice expert evaluation. Detection and measurement of isolated ferroceron are carried out by thin-layer chromatography and spectroscopy in the visible part of the spectrum. The developed method for ferroceron detection in cadaveric material was used in two expert evaluations. Recommendations are offered on the detection of ferroceron in cadaveric and biological material and on resuscitation measures in cases with poisoning with this drug.