Paramagnetic ionic liquids for advanced applications: A review

Fabrication of a magnetic functionalized chitosan hydrogel for effective extraction of aflatoxins from cereals

A magnetic adsorbent was synthesized by coupling magnetic nanoparticles, UiO-66-NH2 and 1-butyl-trimethylimidazole bromide ([BMIM][Br]) to chitosan (CS)-based composite conveniently. A series of modern characterizations were employed to assess its properties. The results showed that UiO-66-NH2 was uniformly distributed within the composite via in-situ growth, which can enhance the porosity obviously. The introduction of various ligands enables the composite to exhibit excellent extraction performance for four aflatoxins (AFs) through multiple interactions. The adsorption mechanism was elucidated and the main factors affecting extraction efficiency were evaluated. Under optimal conditions, the limits of detection (LODs) ranged from 0.08 to 0.56 μg/kg. The established method was successfully utilized to determine AFs from cereal samples (rice, glutinous rice, wheat, soybean, paddy, and corn) with satisfactory recovery of 77% ∼ 119% with relative standard deviations (RSDs) of 1.0% ∼ 11.7% (n = 5). The adsorbent demonstrated sufficient robustness for repeated use at least six times without obvious damage of extraction property.

Investigating a new approach for magnetic ionic liquids: Dispersive liquid-liquid microextraction coupled to pyrolysis gas-chromatography-mass spectrometry to determine flame retardants in sewage sludge samples

This study addresses the analysis of emerging contaminants, often using chromatographic techniques coupled to mass spectrometry. However, sample preparation is often required prior to instrumental analysis, and dispersive liquid-liquid microextraction (DLLME) is a viable strategy in this context. DLLME stands out for its ability to reduce sample and solvent volumes. Notably, dispersive liquid-liquid microextraction using magnetic ionic liquids (MILs) has gained relevance due to the incorporation of paramagnetic components in the chemical structure, thereby eliminating the centrifugation step. A pyrolizer was selected in this work to introduce sample onto the GC column, since the MIL is extremely viscous and incompatible with direct introduction through an autosampler. This study is the first to report the use of a DLLME/MIL technique for sample introduction through a pyrolizer in gas chromatography coupled to mass spectrometry (GC-MS). This approach enables the MIL to be compatible with gas chromatography systems, resulting in optimized analytical and instrument performance. The analysis of polybrominated diphenyl ether flame retardants (PBDEs) was focused on the PBDE congeners 28, 47, 99, 100, and 153 in sewage sludge samples. The [P6,6,6,14+]2[MnCl42-] MIL was thoroughly characterized using UV-Vis, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy, as well as thermal analysis. In the chromatographic method, a pyrolyzer was used in the sample introduction step (Py-GC-MS), and critical injection settings were optimized using multivariate approaches. Optimized conditions were achieved with a temperature of 220 °C, a pyrolysis time of 0.60 min, and an injection volume of 9.00 μL. DLLME optimization was performed through central compound planning (CCD), and optimized training conditions were achieved with 10.0 mg of MIL, 3.00 μL of acetonitrile (ACN) as dispersive solvent, extraction time of 60 s, and volume of a sample of 8.50 mL. Precision was observed to range from 0.11 % to 12.5 %, with limits of detection (LOD) of 44.4 μg L-1 for PBDE 28, 16.9 μg L-1 for PBDE 47 and PBDE 99, 33.0 μg L-1 for PBDE 100 and 375 μg L-1 for PBDE 153. PBDE 28 was identified and analyzed in the sludge sample at a concentration of 800 μg L-1. The use of MIL in dispersive liquid-liquid microextraction combined with pyrolysis gas chromatography-mass spectrometry enables identification and quantification of PBDEs in sewage sludge samples at concentrations down to the µg L-1 level.

Magnetic materials as adsorbents for the pre-concentration and separation of active ingredients from herbal medicine

Herbal medicine (HM) is crucial in disease management and contains complex compounds with few active pharmacological ingredients, presenting challenges in quality control of raw materials and formulations. Effective separation, identification, and analysis of active components are vital for HM efficacy. Traditional methods like liquid-liquid extraction and solid-phase extraction are time-consuming and environmentally concerning, with limitations such as sorbent issues, pressure, and clogging. Magnetic solid-phase extraction uses magnetic sorbents for targeted analyte separation and enrichment, offering rapid, pressure-free separation. However, inorganic magnetic particles' aggregation and oxidation, as well as lack of selectivity, have led to the use of various coatings and modifications to enhance specificity and selectivity for complex herbal samples. This review delves into magnetic composites in HM pretreatment, specifically focusing on encapsulated or modified magnetic nanoparticles and materials like silica, ionic liquids, graphene family derivatives, carbon nanotubes, metal-organic frameworks, covalent organic frameworks, and molecularly imprinted polymers.

Ionic Liquids in Metal, Photo-, Electro-, and (Bio) Catalysis

Ionic liquids (ILs) have unique physicochemical properties that make them advantageous for catalysis, such as low vapor pressure, non-flammability, high thermal and chemical stabilities, and the ability to enhance the activity and stability of (bio)catalysts. ILs can improve the efficiency, selectivity, and sustainability of bio(transformations) by acting as activators of enzymes, selectively dissolving substrates and products, and reducing toxicity. They can also be recycled and reused multiple times without losing their effectiveness. ILs based on imidazolium cation are preferred for structural organization aspects, with a semiorganized layer surrounding the catalyst. ILs act as a container, providing a confined space that allows modulation of electronic and geometric effects, miscibility of reactants and products, and residence time of species. ILs can stabilize ionic and radical species and control the catalytic activity of dynamic processes. Supported IL phase (SILP) derivatives and polymeric ILs (PILs) are good options for molecular engineering of greener catalytic processes. The major factors governing metal, photo-, electro-, and biocatalysts in ILs are discussed in detail based on the vast literature available over the past two and a half decades. Catalytic reactions, ranging from hydrogenation and cross-coupling to oxidations, promoted by homogeneous and heterogeneous catalysts in both single and multiphase conditions, are extensively reviewed and discussed considering the knowledge accumulated until now.

Magnetic Ionic Liquids: Current Achievements and Future Perspectives with a Focus on Computational Approaches

Magnetic ionic liquids (MILs) stand out as a remarkable subclass of ionic liquids (ILs), combining the desirable features of traditional ILs with the unique ability to respond to external magnetic fields. The incorporation of paramagnetic species into their structures endows them with additional attractive features, including thermochromic behavior and luminescence. These exceptional properties position MILs as highly promising materials for diverse applications, such as gas capture, DNA extractions, and sensing technologies. The present Review synthesizes key experimental findings, offering insights into the structural, thermal, magnetic, and optical properties across various MIL families. Special emphasis is placed on unraveling the influence of different paramagnetic species on MILs' behavior and functionality. Additionally, the Review highlights recent advancements in computational approaches applied to MIL research. By leveraging molecular dynamics (MD) simulations and density functional theory (DFT) calculations, these computational techniques have provided invaluable insights into the underlying mechanisms governing MILs' behavior, facilitating accurate property predictions. In conclusion, this Review provides a comprehensive overview of the current state of research on MILs, showcasing their special properties and potential applications while highlighting the indispensable role of computational methods in unraveling the complexities of these intriguing materials. The Review concludes with a forward-looking perspective on the future directions of research in the field of magnetic ionic liquids.

A tuned triboelectric nanogenerator using a magnetic liquid for low-frequency vibration energy harvesting

Wireless sensor networks have developed quickly in recent years, and the use of self-powered technology to replace traditional external power sources to power sensor nodes has become an urgent problem that needs to be solved. As an entirely novel type of self-powered technology, the triboelectric nanogenerator (TENG) has attracted widespread attention, but the inability to achieve adaptive adjustment based on the vibration environment has restricted the development of TENGs. Here, a magnetic liquid triboelectric nanogenerator (ML-TENG) is designed to harvest vibration energy to power sensing nodes, and ML-TENG tuning is achieved using a magnetic liquid to adapt to different vibration environments. The electrical performance of the ML-TENG was investigated by theoretical, experimental, and numerical research. According to the results, the developed ML-TENG responds well to low-frequency vibration, and the instantaneous power is up to 5.40 nW. The tuning function is achieved by adjusting the magnetic field, and the natural frequency can be adjusted between 6.6 Hz and 7.6 Hz. The strong linear connection between the output voltage of the ML-TENG and the external environment's vibration amplitude promotes the monitoring of the vibration environment and lays the groundwork for the creation of wireless sensor networks.

Organometallic Ionic Liquids Containing Sandwich Complexes: Molecular Design, Physical Properties, and Chemical Reactivities

Ionic liquids (ILs) are salts with low melting points and are useful as electrolytes and solvents. We have developed ILs containing cationic metal complexes, which form a family of functional liquids that exhibit unique physical properties and chemical reactivities originating from metal complexes. Our study explores the liquid chemistry in the field of coordination chemistry, where solid-state chemistry is currently the main focus. This review describes the molecular design, physical properties, and reactivities of organometallic ILs containing sandwich or half-sandwich complexes. This paper mainly covers stimuli-responsive ILs, whose magnetic properties, solvent polarities, colors, or structures change by the application of external fields, such as light, heat, and magnetic fields, or by reaction with coordinating molecules.

Coalescence of a Ferrofluid Drop at Its Bulk Surface with or without a Magnetic Field

The coalescence of a ferrofluid drop at its bulk surface, with or without a magnetic field, was investigated experimentally by a high-speed camera. Shape deformations of both the pendant ferrofluid drop and the bulk surface in the axial direction were observed during the approaching process even in the absence of a magnetic field. The angle of the upper pendant peak at the first contact decreases with the magnetic flux density, while the lower ferrofluid peak displays an opposite trend. The coalescing width of the ferrofluid drop follows a power-law relationship. The exponent of 0.64 under medium and high magnetic fields as well as the case without magnetic field confirms the inertial regime of drop coalescence. Under the low magnetic field, the significant exponent increasing from 0.59 to 3.02 at about 4 ms is in coincidence with the sudden change to a smooth coalescing section according to the visualized images. A high-speed microparticle image velocimetry (micro-PIV) technique was employed with a transparent model fluid to reveal the flow fields during the drop coalescence instead of opaque ferrofluids.

Confinement Effects on the Magnetic Ionic Liquid 1-Ethyl-3-methylimidazolium Tetrachloroferrate(III)

Confinement effects for the magnetoresponsive ionic liquid 1-ethyl-3-methylimidazolium tetrachloroferrate(III), [C2mim]FeCl4, are explored from thermal, spectroscopic, and magnetic points of view. Placing the ionic liquid inside SBA-15 mesoporous silica produces a significant impact on the material’s response to temperature, pressure, and magnetic fields. Isobaric thermal experiments show melting point reductions that depend on the pore diameter of the mesopores. The confinement-induced reductions in phase transition temperature follow the Gibbs–Thomson equation if a 1.60 nm non-freezable interfacial layer is postulated to exist along the pore wall. Isothermal pressure-dependent infrared spectroscopy reveals a similar modification to phase transition pressures, with the confined ionic liquid requiring higher pressures to trigger phase transformation than the unconfined system. Confinement also impedes ion transport as activation energies are elevated when the ionic liquid is placed inside the mesopores. Finally, the antiferromagnetic ordering that characterizes unconfined [C2mim]FeCl4 is suppressed when the ionic liquid is confined in 5.39-nm pores. Thus, confinement provides another avenue for manipulating the magnetic properties of this compound.

Preconcentration and determination of five antidepressants from human milk and urine samples by stir bar filled magnetic ionic liquids using liquid-liquid-liquid microextraction-high performance liquid chromatography

A sensitive and straightforward liquid-liquid-liquid microextraction method was developed to preconcentrate and cleanup antidepressants, including mirtazapine, venlafaxine, escitalopram, fluoxetine, and fluvoxamine, from biological samples before analyzing with high-performance liquid chromatography. The essential novelty of this study is using magnetic ionic liquids as the extraction phase in the lumen of hollow fiber and preparing a liquid magnetic stir bar. In the method, polypropylene hollow fiber was utilized as the permeable membrane for the analyte extraction. Six magnetic ionic liquids consisting of the transition metal and rare earth compounds were synthesized and then injected hollow fiber lumen as acceptor phase to extract the antidepressants. Besides, 3-pentanol as a water-immiscible solvent was impregnated in the hollow fiber wall pores. The effective factors in the method were optimized with the central composition design. The resultant calibration curves were linear over the concentration range of 0.8-400.0 ng mL^-1 (R² ≥ 0.996). The method displayed the proper detection limit (0.11-0.24 ng mL^-1 ), the reasonable limit of quantification (≤0.79 ng mL^-1 ), wide linear ranges, high preconcentration factors (≥294.3), and suitable relative standard deviation (2.31-5.47%) for measuring antidepressant medications. Analysis of human milk and urine samples showed acceptable recoveries of 96.5-103.8% with excellent relative standard deviations lower than 5.95%. This article is protected by copyright. All rights reserved.

Guanidinium Hydrophobic Magnetic Ionic Liquid-Based Dispersive Droplet Extraction for the Selective Extraction of DNA

Six hydrophobic magnetic guanidinium ionic liquids (HMILs) were designed and prepared for the extraction of DNA. The physical and thermal properties of the HMILs were characterized using vibrating sample magnetometry, density meter, rotational rheometer, Karl Fischer moisture, Fourier transform infrared spectrometry, and thermogravimetric analysis. Single-stranded DNA and duplex DNA extracted by HMILs can be rapidly collected by a magnet. Three assisted extraction methods, including vortex extraction, mechanical shaking extraction, and ultrasonic extraction, were introduced to extract DNA with HMILs and the extraction efficiencies were evaluated using NanoDrop. Influencing factors of the DNA extraction were comprehensively evaluated, involving the HMIL volume, extraction time, pH, and extraction temperature. The HMIL-based extraction method can well extract DNA from complex matrices and Escherichia coli cell lysates.

Unravelling the Interactions of Magnetic Ionic Liquids by Energy Decomposition Schemes: Towards a Transferable Polarizable Force Field

This work aims at unravelling the interactions in magnetic ionic liquids (MILs) by applying Symmetry-Adapted Perturbation Theory (SAPT) calculations, as well as based on those to set-up a polarisable force field model for these liquids. The targeted MILs comprise two different cations, namely: 1-butyl-3-methylimidazolium ([Bmim]⁺) and 1-ethyl-3-methylimidazolium ([Emim]⁺), along with several metal halides anions such as [FeCl₄]⁻, [FeBr₄]⁻, [ZnCl₃]⁻ and [SnCl₄]²⁻ To begin with, DFT geometry optimisations of such MILs were performed, which in turn revealed that the metallic anions prefer to stay close to the region of the carbon atom between the nitrogen atoms in the imidazolium fragment. Then, a SAPT study was carried out to find the optimal separation of the monomers and the different contributions for their interaction energy. It was found that the main contribution to the interaction energy is the electrostatic interaction component, followed by the dispersion one in most of the cases. The SAPT results were compared with those obtained by employing the local energy decomposition scheme based on the DLPNO-CCSD(T) method, the latter showing slightly lower values for the interaction energy as well as an increase of the distance between the minima centres of mass. Finally, the calculated SAPT interaction energies were found to correlate well with the melting points experimentally measured for these MILs.

New Low-Melting Triply Charged Homoleptic Cr(III)-Based Ionic Liquids in Comparison to Their Singly Charged Heteroleptic Analogues

A series of new low-melting triply charged homoleptic Cr(III)-based ionic liquids of the general formula (RMIm)3[Cr(NCS)6] (R = methyl, ethyl, n-butyl, benzyl) is reported. Their syntheses and properties are described in comparison to their singly charged heteroleptic analogues of the general formula (RMIm)[Cr(NCS)4L2] (R = methyl, ethyl, n-butyl, benzyl; L = pyridine, γ-picoline). In total, sixteen new Reineckate related salts with large imidazolium cations are described. Out of these, five compounds were crystallized, and their structures determined by single-crystal X-ray structure analyses. They all consisted of discrete anions and cations with octahedrally coordinated Cr(III) ions. In the structures, various hydrogen contacts interconnect the entities to build up hydrogen bonded networks. Thermal investigations showed relatively low melting points for the homoleptic complexes. The compounds with the [Cr(NCS)6]3- anion melt without decomposition and are stable up to 200 K above their melting points. The complex salts with the [Cr(NCS)4L2]- anion, in contrast, start to decompose and lose L molecules (Pyr or Pic) already at the melting point.

Ionic liquids as alternative solvents for energy conservation and environmental engineering

Because of industrialization and modernization, phenomenal changes have taken place in almost all spheres of life. Consequently, the consumption of energy resources and the cases of environmental hazards have risen to an unprecedentedly high level. A development model with due consideration to nature and an efficient utilization of energy sources has become the need of the hour, in order to ensure a sustainable balance between the environmental and technological needs. Recent studies have identified the suitability of ionic liquids (ILs), often labeled as ‘green solvents’, in the efficient utilization of energy resources and activities such as bio-extraction, pollution control, CO2 capture, waste management etc. in an environmentally friendly manner. The advent of magnetic ionic liquids (MILs) and deep eutectic solvents (DESs) have opened possibilities for a circular economic approach in this filed. This review intends to analyze the environmental and energy wise consumption of a wide variety of ionic liquids and their potential towards future.

Regeneration of [Bmim]BF4 ionic liquid by ozonation: hydrogen bond roles, synergistic effect, and DFT calculation

Ionic liquids (ILs) are a kind of promising extractants for removing undesirable organics from industrial wastewater and crude oil, etc. Herein, IL regeneration by ozonation was proposed for its recycling. 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄) and phenol were used as the representative IL and organic matter, respectively. The regeneration performance, stability of [Bmim]BF₄, and roles of hydrogen bonds between O₃ and [Bmim]BF₄ in the phenol removal were studied. The experimental results showed that 90.2% of phenol was degraded in [Bmim]BF₄ after ozonation treatment for 30 min with the O₃ concentration of 1.2 mg/L. The nonvolatility of [Bmim]BF₄-made phenol was adequately degraded, while the concentration of phenol increased during ozone treatment in the conventional extractants (ethanol, ethyl acetate, and dichloromethane) due to their high volatility. The reuse experiments, spectra of Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance spectroscopy indicated that [Bmim]BF₄ was steady under the ozonation process. Density functional theory simulation confirmed that hydrogen bonds between [Bmim]⁺ and O₃ could be formed, and calculational results of Hirshfeld charges indicated that the nucleophilicity of O₃ was enhanced by the hydrogen bonds. The enhanced nucleophilicity resulted in the increase of phenol degradation efficiency by ozonation, and the synergistic effect between O₃ and ILs was proportional to the hydrogen bond donor ability of ILs.

Double-enzymes-mediated Fe2+/Fe3+ conversion as magnetic relaxation switch for pesticide residues sensing

It is a great challenge to develop a newly rapid and accurate detection method for pesticide residues. In this work, based on acetylcholinesterase (AChE) and choline oxidase (CHO), a double-enzymes-mediated Fe²⁺/Fe³⁺ conversion as magnetic relaxation switch was explored for the measurement of acetamiprid residue. In the double-enzymes reactions, acetylcholine chloride (ACh) can be catalyzed to produce choline by AChE, which is successively hydrolyzed to betaine and hydrogen peroxide (H₂O₂) by CHO. According to the enzyme inhibition principle, AChE activity will be inactivated in the presence of acetamiprid, thus leading to the less production of H₂O₂. Wherein, Fe²⁺, ACh, AChE and CHO were optimized as the reaction substrates. In the reaction system, acetamiprid can be reflected by the transverse relaxation time (T₂) that related with H₂O₂ mediated Fe²⁺ variations, which was further developed as an enzyme cascade amplification method. The detection linear range is 0.01∼1000 μg mL^-1 (R² = 0.99), and the limit of detection (LOD) is 2.66 ng mL^-1 (S/N = 3, n = 3), behaving a 335-fold improvement in LOD than that of traditional enzyme inhibition method (0.89 μg mL^-1). This method can realize "one-step mixing" detection of acetamiprid, which makes it a promising analytical tool for monitoring pesticide residue in complicated samples.

Metal-Based Ionic Liquids in Oxidative Desulfurization: A Critical Review

Ionic liquids (ILs) as novel functional desulfurization materials have attracted increasing attentions. Metal-based ionic liquids (MILs) are classified into three types of metal chloride ILs, metal oxide ILs, and metal complex ILs based on the definition and basic structure of MILs in this critical review. On the basis of the properties of ILs such as structure designability, super dissolution performance, good thermal and chemical stability, nonflammability, and wide electrochemical window, MILs exhibit unique advantages on hydrophobicity, oxidation performance, and Brönsted-Lewis acidity. Therefore, MILs possess both the absorption and oxidation centers for the intramolecular adsorption and oxidation to improve the oxidative desulfurization (ODS) process. During the novel nonaqueous wet oxidative desulfurization process (Nasil), H₂S can be oxidized into elemental sulfur with hydrophobic MILs, which can be regenerated by oxygen for recycle, to solve the problems of low sulfur capacity, low sulfur quality, and severe secondary pollution in the aqueous Lo-Cat wet oxidative desulfurization process. Another outstanding feature of MILs in ODS is biomimetic catalysis, which has the function of activating molecular oxygen and improving the oxidation performance. Metal oxide ILs and metal complex ILs are used in combination with hydrogen peroxide or oxygen with the existing water to generate a Fenton-like reaction to convert hydrophobic organic sulfur or SO₂ into hydrophilic sulfoxide/sulfone or sulfur acid, respectively. However, the corrosion of Cl^- to the equipment and emulsification phenomenon in the extraction process of sulfoxide/sulfone separation still need further study. Furthermore, the promising strategies to construct highly efficient and green desulfurization processes for large-scale applications are provided.

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).

A gadolinium-based magnetic ionic liquid for dispersive liquid-liquid microextraction

A hydrophobic gadolinium-based magnetic ionic liquid (MIL) was investigated for the first time as an extraction solvent in dispersive liquid–liquid microextraction (DLLME). The tested MIL was composed of trihexyl(tetradecyl)phosphonium cations and paramagnetic gadolinium chloride anions. The prepared MIL showed low water miscibility, reasonable viscosity, markedly high magnetic susceptibility, adequate chemical stability, low UV background, and compatibility with reversed-phase HPLC solvents. These features resulted in a more efficient extraction than the corresponding iron or manganese analogues. Accordingly, the overall method sensitivity and reproducibility were improved, and the analysis time was reduced. The applicability of the proposed MIL was examined through the microextraction of four sartan antihypertensive drugs from aqueous samples followed by reversed-phase HPLC with UV detection at 240 nm. The DLLME procedures were optimized for disperser solvent type, MIL mass, disperser solvent volume, as well as acid, base, and salt addition. The limits of quantitation (LOQs) obtained with the analysis of 1.2-mL samples after DLLME and HPLC were 80, 30, 40, and 160 ng/mL for azilsartan medoxomil, irbesartan, telmisartan, and valsartan, respectively. Correlation coefficients were greater than 0.9988 and RSD values were in the range of 2.48–4.07%. Under the optimized microextraction conditions and using a 5-mL sample volume, enrichment factors were raised from about 40 for all sartans using a 1.2-mL sample to 175, 176, 169, and 103 for azilsartan medoxomil, irbesartan, valsartan, and telmisartan, respectively. The relative extraction recoveries for the studied sartans in river water varied from 82.5 to 101.48% at a spiked concentration of 0.5 μg/mL for telmisartan and irbesartan and 1 μg/mL for azilsartan medoxomil and valsartan.

Design of Ionic-Liquid-Based Hybrid Polymer Materials with a Magnetoactive and Electroactive Multifunctional Response

Multifunctional materials with sensor and actuator capabilities play an increasing role in modern technology. In this scope, hybrid materials with magnetic sensing and an electromechanical actuator response based on magnetic ionic liquids (MILs) and the polymer poly(vinylidene fluoride) (PVDF) have been developed. MILs comprising different cation alkyl chain lengths [C_nmim]⁺ and sharing the same anion [FeCl₄]^- were incorporated at 20 wt % into the PVDF matrix and the morphological, physical, chemical, and functional properties of the materials were evaluated. An increasing IL alkyl chain length leads to the formation of a porous structure, together with an increase in the electroactive PVDF β-phase content of the polymer and a decrease in the crystallinity degree and thermal stability. The magnetic susceptibility of the [C_nmim][FeCl₄]/PVDF films reveals a paramagnetic behavior. The multifunctional response is characterized by a magnetoionic response that decreases with increasing IL alkyl chain length, the highest magnetoionic coefficient (1.06 ± 0.015 V cm^-1 Oe^-1) being observed for [C₂mim][FeCl₄]/PVDF. The electromechanical actuator response is characterized by a highest displacement of 1.1 mm for the [C₄mim][FeCl₄]/PVDF film by applying a voltage of 4 V at a frequency of 100 mHz. Further, their solution processing makes these multiresponsive materials compatible with additive manufacturing technologies.

Allelic discrimination between circulating tumor DNA fragments enabled by a multiplex-qPCR assay containing DNA-enriched magnetic ionic liquids

Multiplex amplification of DNA can be highly valuable in circulating tumor DNA (ctDNA) analysis due to the sheer number of potential mutations. However, commercial ctDNA extraction methods struggle to preconcentrate low concentrations of DNA and require multiple sample handling steps. Recently, magnetic ionic liquids (MILs) have been used to extract DNA and were integrated with a quantitative polymerase chain reaction (qPCR). However, in previous studies, DNA could not be preconcentrated from plasma and only one fragment could be amplified per reaction. In this study, MILs were utilized as DNA extraction solvents and directly integrated into a multiplex-qPCR buffer to simultaneously amplify wild-type KRAS, G12S KRAS, and wild-type BRAF, three clinically-relevant genes whose mutation status can affect the success of anti-EGFR therapy. DNA was desorbed from the MIL solvent during a multiplex-PCR without having a significant effect on the amplification efficiency, and allelic discrimination of single-nucleotide polymorphisms could still be achieved. Enrichment factors over 35 for all three sequences were achieved from Tris buffer using the [N_8,8,8,Bz⁺][Ni(hfacac)₃^-]) and [P_6,6,6,14⁺][Ni(Phtfacac)₃^-] MILs. DNA could still be preconcentrated from 2-fold diluted human plasma using the [N_8,8,8,Bz⁺][Ni(hfacac)₃^-] MIL. Extractions from undiluted plasma were reproducible with the [P_6,6,6,14⁺][Ni(Phtfacac)₃^-] MIL although DNA was not preconcentrated with enrichment factors around 0.6 for all three fragments. Compared to commercial DNA extraction methods (i.e., silica-based spin columns and magnetic beads), the MIL-based extraction achieved higher enrichment factors in Tris buffer and plasma. The ability of the MIL-based dispersive liquid-liquid microextraction (DLLME) direct-multiplex-qPCR method to simultaneously achieve high enrichment factors of multiple DNA fragments from human plasma is highly promising in the field of ctDNA detection.

Magnetic proline-based ionic liquid surfactant as a nano-carrier for hydrophobic drug delivery

Biofriendly and magnetic proline based ionic liquid surfactant demonstrated for drug delivery system.

Magnetic polymerizable surfactants: thermotropic liquid crystal behaviors and construction of nanostructured films

Two polymerizable surfactants, 3-undecylene-1-vinylimidazolium bromide (C11VIMBr) and 3-dodecyl-1-vinylimidazolium bromide (C12VIMBr), were chosen to prepare magnetic surfactant monomers by introducing Mn2+, Gd3+ and Ho3+.

Low-Melting Manganese (II)-Based Ionic Liquids: Syntheses, Structures, Properties and Influence of Trace Impurities

The synthesis of more than 10 new magnetic ionic liquids with [MnX₄]^2- anions, X = Cl, NCS, NCO, is presented. Detailed structural information through single-crystal X-ray diffraction is given for (DMDIm)[Mn(NCS)₄], (BnEt₃N)₂[Mn(NCS)₄], and {(Ph₃P)₂N}₂[Mn(NCO₄)]·0.6H₂O, respectively. All compounds consist of discrete anions and cations with tetrahedrally coordinated Mn (II) atoms. They show paramagnetic behavior as expected for spin-only systems. Melting points are found for several systems below 100 °C classifying them as ionic liquids. Thermal properties are investigated using differential scanning calorimetry (DSC) measurements. The physicochemical properties of density, dynamic viscosity, electrolytic conductivity, and surface tension were measured temperature-dependent of selected samples. These properties are discussed in comparison to similar Co containing systems. An increasing amount of bromide impurity is found to affect the surface tension only up to 3.3%.

Porous ionic liquid polymer: A reusable adsorbent with broad operating pH range for speciation of nitrate and nitrite

Ionic liquids (ILs) are a class of fluids with unique physicochemical properties employing polymeric substances emerging new materials. Solidification of ILs into porous materials generates porous ionic liquid polymers that combine the unique characteristics of ILs with common porous materials and polymers. In this study, it's the first time the porous ionic liquid polymer was chosen as a sorbent for extraction and speciation of nitrite and nitrate. Porous IL was prepared through polymerization of 1-allyl-3-methylimidazolium bromide monomers in the presence of azobisisobutyronitrile (AIBN) and crosslinking of ethylene glycol dimethyl acrylate (EGDMA). Parameters affecting the adsorbent performance were optimized. Under the optimal conditions, correlation coefficient (R²) was 0.9996 and LOD was 0.1 µg L^-1. This method presented the linearity in the concentration range between 0.1-100 µg L^-1 and the relative standard deviation was 3.2%. Finally, the adsorption behavior of the obtained sorbent for nitrate and nitrite determination in various real samples was evaluated. The result indicates that the porous ionic liquid polymer showed high adsorption capacity (233 mg g^-1). The convenient preparation of the porous ionic liquid material, as well as high adsorption capacity for anionic pollutants predicted its broad application potential in anion removal materials.

The Nature of Cation-Anion Interactions in Magnetic Ionic Liquids as Revealed Using High-Pressure Fourier Transform Infrared (FT-IR) Spectroscopy

Magnetic ionic liquids are a group of magneto-responsive compounds that typically possess high ionic conductivities and low vapor pressures. In spite of the general interest in these materials, a number of questions concerning the fundamental interactions among the ions remain unanswered. We used vibrational spectroscopy to gain insight into the nature of these interactions. Intramolecular vibrational modes of the ions are quite sensitive to their local potential energy environments, which are ultimately defined by cation-anion coordination schemes present among the ions. Ambient pressure Fourier transform infrared (FT-IR) spectroscopy indicates comparable interaction motifs for 1-ethyl-3-methylimidazolium tetrachloroferrate(III), [emim]FeCl₄, and 1-ethyl-3-methylimidazolium tetrabromoferrate(III), [emim]FeBr₄, magnetic ionic liquids. However, the vibrational modes of [emim]FeCl₄ generally occur at slightly higher frequencies than those of [emim]FeBr₄. These differences reflect different interaction strengths between the [emim]⁺ cations and FeCl4- or FeBr4- anions. This conclusion is supported by gas-phase ab initio calculations of single [emim]FeCl₄ and [emim]FeBr₄ ion pairs that show longer C-H···Br-Fe interaction lengths compared to C-H···Cl-Fe. Although the IR spectra of [emim]FeCl₄ and [emim]FeBr₄ are comparable at ambient pressure, a different series of spectroscopic changes transpire when pressure is applied to these compounds. This suggests [emim]⁺ cations experience different types of interaction with the anions under high-pressure conditions. The pressure-dependent FT-IR spectra highlights the critical role ligands attached to the tetrahalogenoferrate(III) anions play in modulating cation-anion interactions in magnetic ionic liquids.