Stability In Solvents Research Articles

Enhanced Solvent and Thermal Stability in Cross-Linkable Conjugated Statistical Copolymers for Organic Field-Effect Transistors.

The ability to enhance both the solvent and thermal stability of semiconducting π-conjugated polymers is highly desired for various device-related applications. Herein, a series of poly(3-hexylthiophene)-stat-poly[3-(6-hydroxy)hexylthiophene] (P3HT-stat-P3HHT) statistical copolymers with thermally cross-linkable hydroxyl groups is synthesized and their crystalline structures in three different states, solvent and thermal stability for use in organic field-effect transistors (OFETs) are elucidated. Importantly, these initial P3HT-stat-P3HHT thin films in their as-cast state crystallize well in an edge-on orientation. During annealing at 150 °C, these P3HT-stat-P3HHT occur cross-linked and retain edge-on orientation with increased crystallinity and ordering. In contrast, after high-temperature annealing at 300 °C, their edge-on orientation is significantly destroyed due to the cross-linking of hydroxyl groups at melted state. The correlation between different P3HT-stat-P3HHT and their charge mobilities is scrutinized. These cross-linked P3HT-stat-P3HHT exhibit good solvent resistance property and improved thermal stability in OFETs. Conceptually, such side-chain functionalization approach to improve the stability of P3HT-stat-P3HHT can be conveniently extended to other conjugated polymers for diverse optoelectronic applications.

Organic solvent nanofiltration with nanoparticles aggregation based on electrostatic interaction for molecular separation

Organic solvent nanofiltration (OSN) has been regarded as a promising membrane-based separation technology with great potential in many fields. In this work, based on the strong electrostatic interaction between nanoparticles (NPs) prepared by the quaternized P(VC-r-DMAEMA) (Q-PVD) and hydrolyzed polyacrylonitrile (HPAN) substrate membranes, separation nanochannels were successfully constructed on the surface of membranes by a one-step coating method. The types of the substrates and concentrations of NPs were optimized to obtain the proper performance. The surface morphology, chemical compositions, surface wettability, surface charge, and pore size were characterized. The obtained thin-film nanocomposite (TFN) membranes exhibited excellent stability in various common organic solvents, such as n-heptane, acetonitrile, ethanol, etc. Furthermore, composite membranes showed excellent retention for dyes with specific molecular weights, with a molecular weight cut-off (MWCO) of 825 Da. In particular, the rejection rates of Coomassie brilliant blue (BB) and Bengal rose red (RB) were 96.6% and 97.9%, respectively. Given the above characteristics, the composite membranes are expected to be used in the field of OSN.

Primary amide-functionalized cyclotricatechylene covalent organic frameworks membrane for efficient enrichment of melamine and its derivatives in migration solution of food contact materials.

A highly chemically stable primary amide-functionalized cyclotricatechylene covalent organic framework was synthesized by an irreversible reaction and a post-synthetic modification. It possessed a rod-like morphology and exhibited strong solvent stability owing to the polyether bonds. The material showed good adsorption performance for melamine and its derivatives and adsorption mechanism was investigated by molecular simulations. The adsorbent was coated on the nylon-66 membrane to prepare the enrichment membrane. Under optimized conditions, an in-syringe membrane-based extraction method, combined with ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the analysis of melamine and six melamine derivatives in the migration solution. A good linearity was obtained with correlation coefficients ranging from 0.9924 to 0.9995. The limits of detection were 1-200ng/L and the limits of quantification were 3-500ng/L. This method was successfully applied to the migration solution of sushi bamboo rolling mats with spiked recoveries of 73.2%-115% and relative standard deviations of 0.9%-9.9%. This work shows a practical and perspective approach for the efficient enrichment of food contact material hazards.

Comparison of Four Immobilization Methods for Different Transaminases

Biocatalytic syntheses often require unfavorable conditions, which can adversely affect enzyme stability. Consequently, improving the stability of biocatalysts is needed, and this is often achieved by immobilization. In this study, we aimed to compare the stability of soluble and immobilized transaminases from different species. A cysteine in a consensus sequence was converted to a single aldehyde by the formylglycine-generating enzyme for directed single-point attachment to amine beads. This immobilization was compared to cross-linked enzyme aggregates (CLEAs) and multipoint attachments to glutaraldehyde-functionalized amine- and epoxy-beads. Subsequently, the reactivity and stability (i.e., thermal, storage, and solvent stability) of all soluble and immobilized transaminases were analyzed and compared under different conditions. The effect of immobilization was highly dependent on the type of enzyme, the immobilization strategy, and the application itself, with no superior immobilization technique identified. Immobilization of HAGA-beads often resulted in the highest activities of up to 62 U/g beads, and amine beads were best for the hexameric transaminase from Luminiphilus syltensis. Furthermore, the immobilization of transaminases enabled its reusability for at least 10 cycles, while maintaining full or high activity. Upscaled kinetic resolutions (partially performed in a SpinChemTM reactor) resulted in a high conversion, maintained enantioselectivity, and high product yields, demonstrating their applicability.

Structure and Properties of a Mixed-Ligand Co-MOF That Was Synthesized in Situ from a Single Imidazole–Pyridyl–Tetrazole Trifunctional Ligand

A mixed-ligand Co-MOF (SCNU-Z7) based on a new imidazole–pyridyl–tetrazole trifunctional ligand, 3-(imidazol-1-yl)-5-(tetrazol-5-yl) pyridine (HITP), was constructed using a solvothermal reaction. Single-crystal X-ray diffraction analysis revealed that in addition to HITP, the 5,5′-bis-(2H-tetrazol-5-yl)-[3,3′]bipyridinyl (H2BTBP) ligand obtained by the in situ reaction of HITP is also incorporated into the framework, thus generating a mixed-ligand metal–organic framework (MOF). SCNU-Z7 has a 3D porous framework with 1D channels along the c axis based on tetranuclear secondary building blocks and has a new highly (3,4,10)-connected network topology with the symbol (416·620·89)(43)2(44·62). SCNU-Z7 exhibits high stability in organic solvents but instability in water. Gas adsorption studies indicated that SCNU-Z7 can absorb CO2 more than N2. Magnetic studies indicate the existence of dominant antiferromagnetic interactions between Co(II) atoms. Due to porosity, Co(II) ions, nitrogen-rich conjugated aromatic rings, and uncoordinated nitrogen atoms in its framework, SCNU-Z7 can capture iodine in vapor with a capacity of 2.7 g/g. The strong interactions between the framework and the iodine molecules cause the amorphization of the framework, and approximately 60% of the adsorbed iodine molecules can be stably stored in the framework. This study provides a new possible route for obtaining mixed-ligand MOFs and provides a new example for stably capturing iodine in MOFs via amorphization.

Highly Stable and Photoluminescent CsPbBr3/Cs4PbBr6 Composites for White-Light-Emitting Diodes and Visible Light Communication

Inorganic lead halide perovskite is one of the most excellent fluorescent materials, and it plays an essential role in high-definition display and visible light communication (VLC). Its photochromic properties and stability determine the final performance of light-emitting devices. However, efficiently synthesizing perovskite with high quality and stability remains a significant challenge. Here, we develop a facile and environmentally friendly method for preparing high-stability and strong-emission CsPbBr3/Cs4PbBr6 composites using ultrasonication and liquid paraffin. Tuning the contents of liquid paraffin, bright-emission CsPbBr3/Cs4PbBr6 composite powders with a maximum PLQY of 74% were achieved. Thanks to the protection of the Cs4PbBr6 matrix and liquid paraffin, the photostability, thermostability, and polar solvent stability of CsPbBr3/Cs4PbBr6-LP are significantly improved compared to CsPbBr3 quantum dots and CsPbBr3/Cs4PbBr6 composites that were prepared without liquid paraffin. Moreover, the fabricated CsPbBr3/Cs4PbBr6-LP-based WLEDs show excellent luminescent performance with a power efficiency of 129.5 lm/W and a wide color gamut, with 121% of the NTSC and 94% of the Rec. 2020, demonstrating a promising candidate for displays. In addition, the CsPbBr3/Cs4PbBr6-LP-based WLEDs were also demonstrated in a VLC system. The results suggested the great potential of these high-performance WLEDs as an excitation light source to achieve VLC.

Enzymatic Reactions using Ionic Liquids for Green Sustainable Chemical Process; Stabilization and Activation of Lipases.

The enzymatic reaction is highly respected from an environmentally-friendly point-of-view. Optimization of the reaction media and supporting materials of enzymes must be investigated in parallel with the effort to develop new enzymes. Lipases are frequently used for organic syntheses as synthetic tools even industry because of their acceptance of having a broad range of substrates, stability, and availability. We have investigated the possibility of ILs as both a solvent and activating or stabilization agent of enzymes, in particular, lipase as a model enzyme. ILs allowed recyclable use of a lipase and significant acceleration of transesterification, and also enhanced the stability and reaction activity of a lipase by immobilization through a lyophilization process. We discuss how we enhanced the enzyme capability using the IL engineering focusing on lipase-catalyzed reactions, i. e., realization of the recyclable use of an enzyme, how ILs mediated the enhanced reaction rate, and improved the stability of the enzyme.

Intelligent pH-responsive PMIA membrane with reversible wettability for controllable oil/water and emulsion separation

Intelligent membrane with reversible wettability is an ideal strategy for oil/water separation, but there are still limitations of the reality application of oil/water separation. This effort produced a distinctive, intelligent, pH-sensitive oil/water separation membrane. Modified silica (SiO2-OTES), low-budget titanic oxide (TiO2), decanoic acid (DA), pollution-free chitosan (CTS), and Poly (m-phthaloyl-m-phenylenediamine) (PMIA) are selected to combine to form a superhydrophobic SO@TDC/PM membrane. The wettability of the modified membrane is reversible under the different effects of ammonia treatment and heat treatment. Also, the intelligent membrane is used to achieve controllable separation of oil/water mixtures, and to effectively separate various oil-in-water emulsions and water-in-oil emulsions before and after wettability conversion. In addition, the intelligent membrane has excellent self-cleaning ability, a high separation flux, and high separation efficiency. At the same time, the intelligent membrane itself has good organic solvent, storage, and mechanical stability. The results show that SO@TDC/PM membrane has good reversible wettability, which provides a broad prospect for the development of intelligent response materials with reversible wettability.

Intermolecular cross-linked polymer of intrinsic microporosity-1 (PIM-1)-based thin-film composite hollow fiber membrane for organic solvent nanofiltration

Organic solvent nanofiltration (OSN) is a membrane-based organic solution separation process that has emerged as a viable alternative to energy- and solvent-intensive separation processes. Polymers of intrinsic microporosity (PIMs) are the targets of recent active research on OSN membrane materials because of their unique physicochemical properties, such as solution processability, chemical tunability, robust porosity, and high thermal stability. However, applying PIMs-based membranes in practical OSN applications is still challenging because of their limited organic solvent stability and inevitable decrease in performance. Meanwhile, despite the potential of thin-film composite hollow fiber membranes for OSN, only a few studies have been reported to date. In this study, we fabricated a PIMs-based thin-film composite hollow fiber membrane by dip-coating and improved its organic solvent stability by intermolecular cross-linking. The membrane exhibited pure ethanol permeance of 10.9 LMH/bar and a molecular weight cut-off of 952 g/mol in ethanol. The membrane displayed stable dye rejection performance (>95%) even after immersion in ethanol, acetone, and toluene for seven days. This study demonstrates that intermolecular cross-linking between PIMs polymer chains can improve the organic solvent stability of PIMs-based membranes and provides a desirable strategy to fabricate feasible organic solvent stable PIMs-based thin-film composite hollow fiber membranes for OSN applications.

Lignocellulose-Based Optical Biofilter with High Near-Infrared Transmittance via Lignin Capturing-Fusing Approach.

Near-infrared (NIR) transparent optical filters show great promise in night vision and receiving windows. However, NIR optical filters are generally prepared by laborious, environmentally unfriendly processes that involve metal oxides or petroleum-based polymers. We propose a lignin capturing-fusing approach to manufacturing optical biofilters based on molecular collaboration between lignin and cellulose from waste agricultural biomass. In this process, lignin is captured via self-assembly in a cellulose network; then, the lignin is fused to fill gaps and hold the cellulose fibers tightly. The resulting optical biofilter featured a dense structure and smooth surface with NIR transmittance of ~90%, ultralow haze of close to 0%, strong ultraviolet-visible light blocking (~100% at 400 nm and 57.58% to 98.59% at 550 nm). Further, the optical biofilter has comprehensive stability, including water stability, solvent stability, thermal stability, and environmental stability. Because of its unique properties, the optical biofilter demonstrates potential applications in the NIR region, such as an NIR-transmitting window, NIR night vision, and privacy protection. These applications represent a promising route to produce NIR transparent optical filters starting from lignocellulose biomass waste.

Chiral lanthanide-silver(I) cluster-based metal-organic frameworks exhibiting solvent stability, and tunable photoluminescence.

Due to the lack of effective synthetic strategies, the preparation of chemically stable chiral Ag(I) cluster-based materials for assembly remains challenging. Here, we have developed an approach to synthesize three pairs of chiral Ln-Ag(I) cluster-based metal-organic frameworks (MOFs) named l-LnAg5-3D (Ln = Gd for 1-L, Eu for 2-L, and Tb for 3-L) and d-LnAg5-3D (Ln = Gd for 1-D, Eu for 2-D, and Tb for 3-D) by employing a chiral Ag(I) cluster ({Ag5S6}) as the node and Ln3+ ion as the inorganic linker. Structural analysis revealed that the chiral ligands induced chirality through the entire structure, resulting in a chiral helix arrangement of the C3-symmetric chiral {Ag5S6} nodes and Ln3+ ions. These compounds showed high solvent stability in various polar organic solvents. The solid-state circular dichroism (CD) spectra of compounds l-LnAg5-3D and d-LnAg5-3D exhibited obvious mirror symmetrical peaks. The emission spectra in the solid state revealed that compound 1-L only exhibited the emission peak of {Ag5S6}, while compounds 2-L and 3-L exhibited overlapping peaks of Ln3+ and {Ag5S6} at different excitation wavelengths. This demonstrates the tunable photoluminescence from {Ag5S6} to Ln3+ by introducing different Ln3+ ions and manipulating the excitation wavelengths. The study underscores the enhanced stability of Ag(I) cluster-based MOFs achieved through the incorporation of Ln3+ ions and establishes chiral Ln-Ag(I) cluster-based MOFs as promising candidates for advanced materials with tunable photoluminescence.

Surface engineering of colloidal nanoparticles.

Synthesis of engineered colloidal nanoparticles (NPs) with delicate surface characteristics leads to well-defined physicochemical properties and contributes to multifunctional applications. Surface engineering of colloidal NPs can improve their stability in diverse solvents by inhibiting the interparticle attractive forces, thus providing a prerequisite for further particle manipulation, fabrication of the following materials and biological applications. During the last decades, surface engineering methods for colloidal NPs have been well-developed by numerous researchers. However, accurate control of surface properties is still an important topic. The emerging DNA/protein nanotechnology offers additional possibility of surface modification of NPs and programmable particle self-assembly. Here, we first briefly review the recent progress in surface engineering of colloidal NPs, focusing on the improved stability by grafting suitable small molecules, polymers or biological macromolecules. We then present the practical strategies for nucleic acid surface encoding of NPs and subsequent programmable assembly. Various exciting applications of these unique materials are summarized with a specific focus on the cellular uptake, bio-toxicity, imaging and diagnosis of colloidal NPs in vivo. With the growing interest in colloidal NPs in nano-biological research, we expect that this review can play an instructive role in engineering the surface properties for desired applications.

Ultra-stable CsPbBr3@PbBrOH nanorods for fluorescence labeling application based on methylimidazole-assisted synthesis.

The extension application of perovskites in aqueous media such as bioassays requires the development of a water-stable perovskite with a simple preparation process and low cost. However, the degradation of perovskites in aqueous solution is still a thorny problem. Here, we develop a methylimidazole-assisted two-step synthesis protocol to prepare CsPbBr3@PbBrOH nanorods with superior water stability and remarkable optical properties at room temperature. The synergy of 2-methylimidazole (2-MIM), an N-donor ligand, with water can not only facilitate CsPbBr3 formation and suppress CsPb2Br5 or Cs4PbBr6 formation, but also promote the formation of a PbBrOH shell capping CsPbBr3. 2-MIM is ionized into 2-MIM- in DMF and 2-MIM+ in water. They passivated the surface defects and changed the crystallization environment, leading to water-stable CsPbBr3@PbBrOH. The obtained CsPbBr3@PbBrOH nanorods can still maintain 91% PL intensity after being stored in water for more than 2 months. Furthermore, the CsPbBr3@PbBrOH nanorods show excellent stability in polar solvents, water, and phosphate buffer solution in a wide pH range, as well as better thermal and irradiation stability. In addition, the CsPbBr3@PbBrOH nanorods are further functionalized with polydopamine (PDA) for biomolecular immobilization and immunoassay studies. The resulting assay shows a detection limit of 0.003 ng mL-1 for IgG detection, illustrating important progress towards expanding fluorescence labeling application of perovskite nanomaterials for immunoassays.

Lanthanide-MOFs as multi-responsive photoluminescence sensor for sensitively detecting Fe3+, Cr2O72- and nitrofuran antibiotics.

Fast and selective detection of contaminants plays a key role in meeting human health and environmental concerns. Herein, two groups of isostructural lanthanide MOFs, [Ln(Hpta)(oxalic acid)]·H2O (1-Eu, 2-Gd) and [Ln(pta)(oxalic acid)0.5(H2O)2]·2H2O (3-Eu, 4-Gd) (H2pta = 2-(4-pyridyl)-terephthalic acid, C2O4- = oxalic acid), were synthesized by solvothermal method. Single crystal X-ray diffraction reveals that 1 and 2 are 3D neutral frameworks, while 3 and 4 consist of 2D layers with parallelogram holes and stack into 3D networks through O-H⋯N and O-H⋯O hydrogen bonding interactions. All complexes remain crystalline and stable below 400 °C, suggesting preeminent thermostability. Noteworthily, only 3 shows excellent chemical stability in water and organic solvent. Therefore, the solid-state fluorescence spectrum was used to characterize 3 which exhibited intense red luminescence. The N active sites in the pore channels of 3 are conducive to displaying a distinct quenching effect for Fe3+ cations in aqueous solutions, Cr2O72- anions in DMF and DMA solutions, and nitrofuran antibiotics in the DMF solvent. Overall, 3 is a prospective luminescent sensor for detecting Fe3+, Cr2O72- and nitrofuran antibiotics.

Current Status and Future Directions in Environmental Stability of Sulfide Solid-State Electrolytes for All-Solid-State Batteries

Recently, sulfide-based solid-state electrolytes (SSEs) have attracted much attention owing to their high ionic conductivity and feasible mechanical features. The environmental stability of sulfide-based SSEs is one of the critical aspects due to the possible decomposition, and ionic conductivity change will affect the fabrication and electrochemical performance of the batteries. Thus, important efforts have been made to reveal and improve their environmental stability, and a timely summary of the progress is urgently needed. In this review, we first clarify the definition of environmental stability and its significance in the context of practical use. After indicating the degradation mechanisms of sulfide-based SSEs, we summarize several effective strategies to improve their stability and also highlight the related theoretical studies. The stability of organic solvents of sulfide SSEs is also summarized and discussed, which may help reliable sulfide SSEs in the battery system. The main target of this review is to gain insights and provide useful guidance to further improve the environmental stability of sulfide SSEs, which will finally promote the commercialization of sulfide-based all-solid-state batteries.

CsPbBr3 perovskite quantum dot decorated ZIF-8 MOF: a selective dual recognition fluorometric visual probe for 4-nitroaniline and rhodamine blue.

The uses of highly luminescent perovskite quantum dots in real analytical detection were limited by their supersensitive nature. Here, we have designed a CsPbBr3 perovskite based fluorometric sensor by integrating them with a zeolitic imidazole framework (ZIF-8) via an in situ one step technique and established its stability in aqueous and other polar solvents. The CsPbBr3@ZIF-8 luminescence sensor functioned excellently for the trace detection of 4-nitroaniline and rhodamine blue dye molecules with a detection limit value of 8.367 ppb and 0.088 ppm, respectively. A comprehensive investigation found that the quenching of the fluorescence signal occurred via fluorescence resonance energy transfer (FRET) for rhodamine blue dye and a H-bonding interaction induced trap density mediated quenching mechanism was responsible for 4-NA detection. The potential of this suggested sensor as a cheap portable test paper probe for analyte detection was also explored. This study introduces CsPbBr3 as a cutting-edge sensing platform for industrial pollutants such as dye molecules and nitroaromatics.

An ultra-fast UV-electrochemical sensor based on Cu-MOF for highly sensitive and selective detection of ferric ions.

A 2D Cu-MOF: {[CuL(H2O)]}n (Cu-1, H2L = 3,4-ethylene dioxythiophene-2,5-dicarboxylic acid) was synthesized using the hydrothermal method. Cu-1 showed excellent solvent stability and was used to fabricate a UV ferric ion sensor. An ultra-low limit of detection (LOD) at 14.5 fM was obtained. Furthermore, N,N-dimethylformamide (DMF) as a 'turn-off' switch was introduced into the Cu-1 framework to construct another 2D Cu-MOF: {[CuL(DMF)]}n (Cu-2) by a single crystal to single crystal (SCSC) transformation method. Cu-2 lost the ability to recognize ferric ions and the switching effect of Fe3+ recognition was realized. Cyclic voltammograms (CVs) were employed to investigate this conversion process and provided a way for explaining the interaction mechanism between Cu-1 and ferric ions. We present an approach for designing and synthesizing MOFs that are suitable for ion sensing.

Low-Energy Shape Resonances of a Nucleobase in Water.

When high-energy radiation passes through aqueous material, low-energy electrons are produced which cause DNA damage. Electronic states of anionic nucleobases have been suggested as an entrance channel to capture the electron. However, identifying these electronic resonances have been restricted to gas-phase electron-nucleobase studies and offer limited insight into the resonances available within the aqueous environment of DNA. Here, resonance and detachment energies of the micro-hydrated uracil pyrimidine nucleobase anion are determined by two-dimensional photoelectron spectroscopy and are shown to extrapolate linearly with cluster size. This extrapolation allows the corresponding resonance and detachment energies to be determined for uracil in aqueous solution as well as the reorganization energy associated with electron capture. Two shape resonances are clearly identified that can capture low-energy electrons and subsequently form the radical anion by solvent stabilization and internal conversion to the ground electronic state. The resonances and their dynamics probed here are the nucleobase-centered doorway states for low-energy electron capture and damage in DNA.

Calcium-alginate/HKUST-1 interlayer-assisted interfacial polymerization reaction enhances performance of solvent-resistant nanofiltration membranes

This study aimed to further enhance the solvent stability and flux of organic solvent-resistant nanofiltration (OSN) membranes. Based on hexane diamine cross-linked polyetherimide (PEI) ultrafiltration membranes, in-situ calcium alginate (CaAlg) hydrogel doped with HKUST-1 was constructed as an interlayer, and then the OSN membrane with an integral covalent bond structure was constructed from interfacial polymerization reaction and NN dimethylformamide (DMF) activation. The membrane showed ultra-thinness (polyamide (PA) layer thickness reduced from 97 to 11 nm), large surface area (surface roughness increased from 75.6 to 113 nm), high hydrophilicity (water contact angle reduced from 60.1° to 54.45°), and negative charge. The CaAlg-HKUST-1 interlayer limited the piperazine diffusion rate by hydrogen bonding and covalent bonding, etc., reduced the thickness of the PA layer, and linked the base membrane and the PA layer by its internal integral covalent bonding, which effectively enhanced the structural stability of the OSN membrane. The PA/CaAlg-HKUST-16/PEI membrane achieved a flux of 29.4 L·m−2·h−1 in ethanol and a rejection of 94.7 % in 0.1 g·L-1 methyl blue. Different dye rejection tests, solvent flux tests, DMF and acetone immersion tests, fouling resistance tests, and continuous operation tests show PA/CaAlg-HKUST-16/PEI membrane has better solvent resistance, dye separation performance, and stable membrane flux. Hence, it has great application prospects in the fields of organic solvents and other types of wastewater treatment.

A Robust Molecular Porous Material for C2 H2 /CO2 Separation.

A molecular porous material, MPM-2, comprised of cationic [Ni2 (AlF6 )(pzH)8 (H2 O)2 ] and anionic [Ni2 Al2 F11 (pzH)8 (H2 O)2 ] complexes that generate a charge-assisted hydrogen-bonded network with pcu topology is reported. The packing in MPM-2 is sustained by multiple interionic hydrogen bonding interactions that afford ultramicroporous channels between dense layers of anionic units. MPM-2 is found to exhibit excellent stability in water (>1year). Unlike most hydrogen-bonded organic frameworks which typically show poor stability in organic solvents, MPM-2 exhibited excellent stability with respect to various organic solvents for at least two days. MPM-2 is found to be permanently porous with gas sorption isotherms at 298K revealing a strong affinity for C2 H2 over CO2 thanks to a high (ΔQst )AC [Qst (C2 H2 ) - Qst (CO2 )] of 13.7kJ mol-1 at low coverage. Dynamic column breakthrough experiments on MPM-2 demonstrated the separation of C2 H2 from a 1:1 C2 H2 /CO2 mixture at 298 K with effluent CO2 purity of 99.995% and C2 H2 purity of >95% after temperature-programmed desorption. C-H···F interactions between C2 H2 molecules and F atoms of AlF6 3- are found to enable high selectivity toward C2 H2 , as determined by density functional theory simulations.