Tetrachloroferrate Anion Research Articles

Effervescence tablets based on magnetic ionic liquids as simple microdevices for the in situ dispersive liquid-liquid microextraction of urinary biomarkers

BackgroundMagnetic ionic liquids (MILs) have been explored in dispersive liquid-liquid microextraction (DLLME). Their usage allows to substitute centrifugation and/or filtration steps by a quick magnetic separation. Besides, effervescence-assisted DLLME is one of the most known options to improve the dispersion of the extractant in the sample, while allowing to avoid the consumption of external energy during dispersion. Despite these interesting features, only one study incorporates MILs containing the tetrachloroferrate anion in effervescence tablets. These MILs are highly viscous and liquid at room temperature, thus compromising the stability of the tablets when used as extraction microdevices in effervescence-assisted DLLME, and only allowing their use in the conventional MIL-DLLME mode. ResultsA new class of effervescence tablets containing a Ni(II)-based MIL, that is solid at room temperature, is here proposed. This type of tablets permits their use, for first time, in the in situ DLLME mode, occurring through the transformation of a water-soluble MIL into a water-insoluble MIL microdroplet. This way, the tablet formulation included: the MIL, the metathesis reagent lithium bis[(trifluoromethyl)sulfonyl]imide, NaH2PO4 and K2CO3 as effervescence precursors salts, and Na2SO4 as salting-out and desiccating agent. The method is combined with high-performance liquid-chromatography and both fluorescence and ultraviolet detection, for the determination of monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and benzophenones (BPs), as biomarkers in urine. The method simply involved the addition of the effervescence tablet to the sample, thus taken place simultaneously the effervescence process and the metathesis reaction, without requiring any external energy consumption. The method presented limits of detection down to 10 ng L−1 for OH-PAHs and to 0.60 μg L−1 for BPs, inter-day relative standard deviations lower than 17 %, and average relative recoveries of 94 % in urine. The determined OH-PAHs contents in urine were between 0.40 and 16 μg L−1, and between 17.8 and 334 μg L−1 for BPs. SignificanceWe have developed the first MIL-based effervescence tablets that are completely solid, thus improving the stability and robustness of these microdevices with respect to previously reported tablets involving MILs, while permitting to perform into the in situ DLLME mode (thus gaining in extraction efficiency). This approach including the MIL-based effervescence tablets constitutes an alternative on-site platform for the analysis of urine, as satisfactory precision, accuracy, and sensitivity are achieved despite not involving any external energy input within the analytical sample preparation setup. This method also constitutes the first application of MIL-based effervescence tablets for bioanalysis.

An investigative study on different magnetic ionic liquids to be used as a lubricant and sealant in a vacuum pump

The aim of this work is to explore the possibility of using a magnetic ionic liquid as both a lubricant and sealant in a vacuum pump. The current lubricant in use is due to become obsolete due to incoming legislation on fluorinated compounds. The long-term goal is to use a magnetic field to hold the novel lubricant in place to create a better seal and thus reduce pressure more effectively whilst also lubricating the necessary mechanical parts. This paper explores physical properties (contact angle, viscosity, coefficient of friction (COF) and magnetism) and chemical properties (thermal stability and chemical stability as deduced by X-ray photoelectron spectroscopy (XPS)) of three ionic liquids based on imidazolium cations with varying length of alkyl side chain and a tetrachloroferrate anion along with two control lubricants which are used currently in the field and based upon perfluoropolyether (PFPE). The work shows that the three magnetic ionic liquids possess a lower COF value than the two control lubricants when measured using a Bruker UMT TriboLab suggesting they may perform better in the real life vacuum pump. Upon analysis of the three ionic liquid samples after tribological testing using XPS, it was shown that the ionic liquid samples displayed minor differences in spectra suggesting good stability with no obvious decomposition or degradation of the sample.

Preparation, thermal properties and electrical conductivity of solutions of pyridinium ionic liquids with tetrachloroferrate anion

Thermal stability of N -alkylpyridinium tetrachloroferrates(III) [C5H5NR]FeCl4 [R = C4H9, (CH2)3CN, CH2C6H5, C8H17, C10H21] in air in the range of 25-600°C was studied, as well as the thermal stability of N -alkylpyridinium chlorides. The equivalent electrical conductivity of N -alkylpyridinium tetrachloroferrates(III) in acetonitrile solution at 25°C was investigated. The ionic association constants K a , the limiting molar electrical conductivity (λ0) and the standard Gibbs energy of the association (Δ G °) in acetonitrile solutions were calculated based on conductometric data by the Lee-Wheaton method.

Preparation, Thermal Properties, and Electrical Conductivity of Solutions of Pyridinium Ionic Liquids with Tetrachloroferrate Anion

Preparation, Thermal Properties, and Electrical Conductivity of Solutions of Pyridinium Ionic Liquids with Tetrachloroferrate Anion

Liquid-crystalline behavior and magnetorheological effect of PVC-based ionic polymers with tetrachloroferrate anions

• Ionic liquid-crystalline (LC) polymers with FeCl 4 − were synthesized by PVC and FeCl 3 . • The magnetorheological (MR) effect and LC behavior were investigated. • The MR fluids were fabricated by the ionic polymer and silicone oil. • The MR effect was caused by a synergistic effect between the LC orientation and rearrangement of FeCl 4 − . Ionic polymers based on tetrachloroferrate anions (FeCl 4 − ) have become one of the attractive functional materials due to their magnetic property. Series of polyvinyl chloride (PVC)-based ionic polymers ([PBCs][FeCl 4 ]) containing tetrachloroferrate anions were prepared by self-assembly using PVC, cholesteric pyridine-3,5-dicarbonate, 4,4 -bipyridine and FeCl 3 ·6H 2 O, and their liquid-crystalline (LC) behavior and magnetorheological (MR) effect were investigated in this study. The chemical structure, thermal properties and LC behavior were characterized by various equipment and instruments. The magnetic field response behavior, MR effect, and sedimentation stability were investigated by various technical methods. The [PBCs][FeCl 4 ] showed smectic A phase on heating and cooling cycles. The magnetorheological fluids (MRFs) were fabricated by the [PBCs][FeCl 4 ] polymers as suspended particles and silicone oil as carrier liquids, which presented a Bingham flow characteristics under an external magnetic field. For these [PBCs][FeCl 4 ]-based MRFs, both shear stress and magnetorheological effects increased with the increase of magnetic field strength, and it exhibited a maximum MR efficiency of 15.3 at 1.23 s −1 of shear rate under 80 kA/m of magnetic field strength. The MR effect of the [PBCs][FeCl 4 ]-based fluids was originated from a synergistic effect between the LC orientation of the mesogens and rearrangement of the FeCl 4 − anions when an external magnetic field was applied.

Tuning the 1H NMR Paramagnetic Relaxation Enhancement and Local Order of [Aliquat]+-Based Systems Mixed with DMSO.

Understanding the behavior of a chemical compound at a molecular level is fundamental, not only to explain its macroscopic properties, but also to enable the control and optimization of these properties. The present work aims to characterize a set of systems based on the ionic liquids [Aliquat][Cl] and [Aliquat][FeCl] and on mixtures of these with different concentrations of DMSO by means of H NMR relaxometry, diffusometry and X-ray diffractometry. Without DMSO, the compounds reveal locally ordered domains, which are large enough to induce order fluctuation as a significant relaxation pathway, and present paramagnetic relaxation enhancement for the [Aliquat][Cl] and [Aliquat][FeCl] mixture. The addition of DMSO provides a way of tuning both the local order of these systems and the relaxation enhancement produced by the tetrachloroferrate anion. Very small DMSO volume concentrations (at least up to 1%) lead to enhanced paramagnetic relaxation without compromising the locally ordered domains. Larger DMSO concentrations gradually destroy these domains and reduce the effect of paramagnetic relaxation, while solvating the ions present in the mixtures. The paramagnetic relaxation was explained as a correlated combination of inner and outer-sphere mechanisms, in line with the size and structure differences between cation and anion. This study presents a robust method of characterizing paramagnetic ionic systems and obtaining a consistent analysis for a large set of samples having different co-solvent concentrations.

Synthesis, structural analysis, electrochemical and magnetic properties of tetrachloroferrate ionic liquids

Eight ionic liquids have been synthesized with the tetrachloroferrate anion and varying cations, with the general formula of [RA]+[FeCl4]− (R = –CH3, –CH2C6H5; A = pyridine, benzimidazole, trimethylamine, triphenylphosphine).

Synthesis and characterization of a novel organic–inorganic hybrid salt and its application as a highly effectual Brønsted–Lewis acidic catalyst for the production of N,N′‐alkylidene bisamides

In this research, a novel organic–inorganic hybrid salt, namely, N1,N1,N2,N2‐tetramethyl‐N1,N2‐bis(sulfo)ethane‐1,2‐diaminium tetrachloroferrate ([TMBSED][FeCl4]2) was prepared and characterized by Fourier‐transform infrared spectroscopy (FT‐IR), energy‐dispersive X‐ray spectroscopy (EDX), elemental mapping, field emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), thermal gravimetric (TG), differential thermal gravimetric (DTG), and vibrating‐sample magnetometry (VSM) analyses. Catalytic activity of the hybrid salt was tested for the synthesis of N,N′‐alkylidene bisamides through the reaction of benzamide (2 eq.) and aromatic aldehydes (1 eq.) under solvent‐free conditions in which the products were obtained in high yields and short reaction times. The catalyst was superior to many of the reported catalysts in terms of two or more of these factors: the reaction medium and temperature, yield, time, and turnover frequency (TOF). [TMBSED][FeCl4]2 is a Brønsted–Lewis acidic catalyst; there are two SO3H groups (as Brønsted acidic sites) and two tetrachloroferrate anions (as Lewis acidic sites) in its structure. Highly effectiveness of the catalyst for the synthesis of N,N′‐alkylidene bisamides can be attributed to synergy of the Brønsted and Lewis acids and also possessing two sites of each acid.

Nonaqueous synthesis of magnetite nanoparticles via oxidation of tetrachloroferrate anions by pyridine-N-oxide

Fe3O4 nanoparticles were prepared from a salt comprising a tetrachloroferrate anion and a methyltrioctylammonium cation in toluene using ethylenediamine as a reductant and pyridine-N-oxide as an oxygen donor and an oxidant. The X-ray diffraction (XRD) analysis, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy showed that the product was Fe3O4. Water content measurement with a Karl Fischer moisture meter showed the presence of only a small amount of water in the present system, indicating a limited contribution of water to the formation of Fe3O4 nanoparticles. The Fe3O4 nanoparticle size based on transmission electron microscopy (TEM) observation was approximately 10–30 nm, a result consistent with the crystallite diameter estimated by Scherrer's equation (15.7 nm). A possible reaction mechanism involves the reduction of Fe3+ to Fe2+ by ethylenediamine, coordination of both ethylenediamine and pyridine-N-oxide to Fe2+, and oxidation of a part of Fe2+, leading to a mixed-valence iron-oxygen network, which was a precursor of Fe3O4 nanoparticles. As concerns magnetic properties, saturation magnetization of the product was 57 emu g−1. Both the coercivity and remanent magnetization were nearly zero and the similar decreases in magnetization were observed above the blocking temperature in the zero-field-cooled and field-cooled curves, results indicating the formation of superparamagnetic Fe3O4 nanoparticles.

Preparation of a Magnetic-responsive Polycation with a Tetrachloroferrate Anion

Poly[3-(methacrylamido)propyltrimethylammonium chloride] (PMAPTAC) with a well-controlled structure was reacted with FeCl3 to exchange the counter anion from chloride (Cl−) to tetrachloroferrate (FeCl4−) to prepare a magnetic-responsive polymer (PMAPTAFe). PMAPTAFe powder was attracted to a neodymium magnet. A cast film of PMAPTAFe, which can be prepared from the aqueous solution, also showed magnetic-responsive behavior.

Reversible Structural Phase Transition and Dielectric Switches Induced by Disordering‐Ordering Motion of Tetrachloroferrate (III) Anions

AbstractReversible phase transitions triggered by guest AX4 type metal structural anions such as AuCl4−, FeCl4− etc are sparely documented before. Here we reported a host–guest clathrate, 18‐crown‐6 potassium tetrachloroferrate, [K2(C12H24O6)]2+⋅[FeCl4]22–(1) which exhibits reversible phase transition around 135 K. This special phase transition behaviours were further confirmed by the heat and dielectric anomalies in the vicinity of 135 K. The structural transition mechanism can be attributed to the ordering‐disordering motion of the tetrachloroferrate anions. Its switchable dielectric behaviours around the phase transition point suggest it maybe a potential material for dielectric switches.

Magnetic ionic plastic crystal: choline[FeCl4

A novel organic ionic plastic crystal (OIPC) based on a quaternary ammonium cation and a tetrachloroferrate anion has been synthesized with the intention of combining the properties of the ionic plastic crystal and the magnetism originating from the iron incorporated in the anion. The thermal analysis of the obtained OIPC showed a solid-solid phase transition below room temperature and a high melting point above 220 °C, indicating their plastic crystalline behaviour over a wide temperature range, as well as thermal stability up to approximately 200 °C. The magnetization measurements show the presence of three-dimensional antiferromagnetic ordering below 4 K. The results from electrochemical characterization display a solid-state ionic conduction sufficiently high and stable (between 10(-2.7) and 10(-3.6) S cm(-1) from 20 to 180 °C) for electrochemical applications.

ChemInform Abstract: Iron(III)‐Based Ionic Liquid‐Catalyzed Regioselective Benzylation of Arenes and Heteroarenes.

AbstractThe easily prepared catalyst is easy to handle and efficient in the presented reaction.

Iron(iii)-based ionic liquid-catalyzed regioselective benzylation of arenes and heteroarenes

An easily prepared Fe(III)-derived Lewis acid ionic liquid ([C4mim][FeCl4]), being comprised of 1-butyl-3-methyl imidazolium cation and tetrachloroferrate anion, was found to be an efficient, recyclable catalyst for benzylation of various arenes/heteroarenes into the diarylmethanes derivatives under mild reaction conditions without utilization of additional organic solvent. Interestingly, the acidity of [C4mim][FeCl4] could account for its catalytic activity in promoting the Lewis acid-catalyzed alkylation. Notably, this type of Fe(III)-based ionic liquid (IL) shows excellent stability, and could be easily recovered, and reused for five times without significant loss of its catalytic activity.

Magnetic and Transport Properties of Organic Radical Ion Salts Containing Metal Ions

Two isomorphous TMTSF cation radical salts with tetrachlorometalate anion, TMTSF·FeCl4 (ρrt = 40 Ωcm), and TMTSF·GaCl4 (ρrt = 20 Ωcm) were prepared. The crystal containing tetrachloroferrate anion undergoes an antiferromagnetic ordering below Tn = 4K with the easy axis perpendicular to the TMTSF stacking direction. X-ray crystallographic analysis of the crystal reveals that Cl atoms of the anions closely contact with Se atoms of the donor molecules and suggests that the spin ordering is mediated by magnetic interaction between donors and anions.

Magnetic and transport properties of organic radical ion salts containing tetrahalogenoferrate anion

A molecular antiferromagnet ( T N = 4 K) crystal TMTSF·FeCl 4 was prepared, in which antiferromagnetic interaction between localized spins on tetrachloroferrate anion are mediated by π-electrons on donor molecules. By contrast, in BMDT-TTF(MT)·FeCl 4 crystal, d-spins and π-electrons are magnetically isolated from each other.