Zwitterionic Research Articles

Dimerization of Intermediate P+–C–O– Dipolar Ions into Carbaphosphatrane Derivatives during Intramolecular Cyclization of 2-R-4,4-Bis(trifluoromethyl)benzo[f][1,3,2]dioxaphosphepin-5-ones

Dimerization of Intermediate P+–C–O– Dipolar Ions into Carbaphosphatrane Derivatives during Intramolecular Cyclization of 2-R-4,4-Bis(trifluoromethyl)benzo[f][1,3,2]dioxaphosphepin-5-ones

Thermodynamics of aggregation and modulation of Rheo-Thermal properties of hydroxypropyl cellulose by imidazolium ionic liquids

Mixtures based on cellulose derivatives/ionic liquids (ILs) are potential viscosity modifiers for enhanced oil recovery (EOR). This paper investigates the thermodynamic of monocationic imidazolium ionic liquids (1-alkyl-3-methylimidazolium bromide, CnMIMBr) aggregation with hydroxypropyl cellulose (HPC) in the dilute regime and the modulation of its rheological and thermal properties in the semi-dilute regime. The outcomes showed that binding occurs by hydrophobic interactions between the alkyl chain of ILs and hydroxypropyl group on HPC and by ion–dipole interactions, and it is driven by entropy. The addition of ILs produced a significant increase in the HPC solutions' viscosity, which depends on the concentration and alkyl chain length of the ILs (n = 10, 12, 14, 16). Moreover, the presence of ILs produces an effect salt-in delaying the HPC phase separation. These findings highlight the role of ILs on the rheological and thermal properties of HPC, opening new possibilities for the design of new complex mixtures.

Quaternary Ammonium Salts Interact with Enolates and Sulfonates via Formation of Multiple +N-C-H Hydrogen Bonding Interactions

We report herein sharp physical evidence, i.e., single-crystal X-ray diffraction and 1H-NMR spectral data, confirming that quaternary ammonium species interact with anions via a set of directional ion–dipole cooperative +N-C-H unusual H-bonding interactions and not via pure non-directional ionic electrostatic interactions. This finding, which has been often invoked by calculations, is herein substantiated by the preparation of two model compounds and an analysis of their X-ray crystal structures in the solid state and 1H-NMR spectra in solution. These observations are particularly pertinent for the rational design of novel catalyses and catalysts and providing guidance to an understanding of these species in solution and during asymmetric enantioselective catalysis.

Stable High-Temperature Lithium-Metal Batteries Enabled by Strong Multiple Ion-Dipole Interactions.

Lithium-metal batteries (LMBs) capable of operating stably at high temperature application scenarios are highly desirable. Conventional lithium-ion batteries could only work stably under 60 °C because of the thermal instability of electrolyte at elevated temperature. Here we design and develop a thermal stable electrolyte based on stable solvation structure using multiple ion-dipole interactions. The strong coordination in solvated structure of electrolyte defines the Li deposition behaviour and the evolution of solid electrolyte interphase at high temperature, which is important to achieve high Li Coulombic efficiency and avoid Li dendritic growth. For high mass loading LiFePO4 -Li cells, the cells at 60 °C with conventional electrolyte easily run into failures, but the cells with our electrolyte at 90 °C and 100 °C could cycle more than 120 and 50 cycles respectively. This work provides new insight into electrolyte design and contributes to the development of high temperature LMBs.

Stable High‐Temperature Lithium‐Metal Batteries Enabled by Strong Multiple Ion–Dipole Interactions

AbstractLithium‐metal batteries (LMBs) capable of operating stably at high temperature application scenarios are highly desirable. Conventional lithium‐ion batteries could only work stably under 60 °C because of the thermal instability of electrolyte at elevated temperature. Here we design and develop a thermal stable electrolyte based on stable solvation structure using multiple ion–dipole interactions. The strong coordination in solvated structure of electrolyte defines the Li deposition behaviour and the evolution of solid electrolyte interphase at high temperature, which is important to achieve high Li Coulombic efficiency and avoid Li dendritic growth. For high mass loading LiFePO4‐Li cells, the cells at 60 °C with conventional electrolyte easily run into failures, but the cells with our electrolyte at 90 °C and 100 °C could cycle more than 120 and 50 cycles respectively. This work provides new insight into electrolyte design and contributes to the development of high temperature LMBs.

Interactions and dynamics of cations and interlayer quest molecules in nontronite and nontronite–formamide intercalation

Nontronite is a swelling clay mineral. Between the layers, it contains water and cations. Nontronite can be easily modified by intercalation. This work focuses on characterizing unmodified nontronite and nontronite intercalated with formamide. Thermal measurements, infrared spectroscopy, X–ray diffraction, and dielectric relaxation measurements were made to evaluate the interactions of the guest molecules with the host layers. A startling effect was observed in dielectric experiments: the low–frequency permittivity detected in nontronite was much larger than in the material intercalated with formamide, the molecule with a high dipole moment. To explain this effect, it was assumed that the low–frequency dielectric relaxation was associated with the movement of interlayer ions. Dehydration of nontronite, which is a stage of preparation for intercalation, can probably fix some ions in hexagonal cavities (privileged positions). Subsequent intercalation of nontronite by formamide does not bring back the mobility of ions, and the low–frequency electric permittivity remains relatively low. To achieve mobility of the cations, an expansion of the interlayer space is required, and ion–dipole interactions with guest molecules should be present.

A green 3-step combined modification for the preparation of biomass sorbent from waste chestnut thorns shell to efficient removal of methylene blue

Although several green methods for the preparation of biomass adsorbents have been proposed, the low adsorption performance of the biomass adsorbents prepared by these methods has limited the development of this technological route. This is the first work that uses an ultrasound-assisted binary solvent system and low temperature ice crystal fixation to achieve high adsorption performance of a biomass sorbent. Chestnut thorns shell (CTS) sorbent with high adsorption performance on MB was successfully prepared with an adsorption performance of 305.81 mg/g, which is on par with most high temperature carbonized adsorbents. Further reaction kinetics, TEM, XPS and FTIR studies showed that the MB adsorption of CTS was through electrostatic attraction, hydrogen bonding, ion–dipole interaction and π-π interaction. After five cycles, the adsorption capacity of the adsorbent remained at a high level. This work provided an effective strategy for safer and greener preparation of high adsorption performance adsorbents from agroforestry waste.

Expanded Azaporphyrins Consisting of Multiple BODIPY Units: Global Aromaticity and High Affinities Towards Alkali Metal Ions

AbstractThe one‐pot self‐coupling reaction of 3‐amino‐5‐bromo‐BODIPY 9 under Buchwald–Hartwig amination conditions gave nitrogen‐bridged cyclic BODIPY tetramer 10, pentamer 11, and hexamer 12. Oxidation of 10, 11, and 12 in the presence of alkali metal ions provided 13, 15, and 16, respectively, as the first examples of expanded azaporphyrins possessing more than six pyrrole rings. Curiously, the oxidation even in the absence of alkali metal ions gave the same complexes as a result of spontaneous complexation. 10–12 showed large association constants (104–106 M−1) with K+ and Na+, but the spontaneous complexations were not observed, indicating the extremely high affinities of 13–16 toward alkali metal ions, which can be ascribed to the multiple and effective ion–dipole interaction of the alkali metal ion with the negatively polarized F atoms of the BF2 walls surrounding the cavity. Importantly, 13, 14, and 15 show diatropic ring currents as a result of global aromaticity.

Tailoring electric dipole of hole-transporting material p-dopants for perovskite solar cells

•Efficient doping of PTAA via regulatory molecular dipole •Surface doping of perovskite via oriented dipole •Trap states restrain via the oriented dipole •High efficiency of modules based on PTAA Li-TFSI/t-BP are the most widely employed p-dopants for hole-transporting materials (HTMs) within the state-of-the-art perovskite solar cells (PSCs). The hygroscopicity and migration of these dopants, however, lead to devices with limited stability. To solve this problem, we report here on a diphenyl iodide cation and pentafluorophenyl boric acid anion-based dopant (DIC-PBA) with an oriented interfacial dipole moment as an alternative to Li-TFSI/t-BP. Theoretical and experimental data reveal that DIC-PBA exhibits deep doping of poly[bis(4-phenyl)(2,4,6-triMethylphenyl)aMine] (PTAA) and also creates p-doping of perovskite surface, which originates from ionic interactions-derived dipole arrangement that yields fast interfacial charge transport. The improved intrinsic stability of PSCs originates from the inhibition of dipole moment degeneration on the perovskite surface. Devices prepared with DIC-PBA yielded high efficiency of 22.86%, and the modules (aperture area: 33.2 cm2) efficiency reached 19.13%. Importantly, the storage stability also significantly improved exceeding to 90% after aging 1,200 h under air ambient. Li-TFSI/t-BP are the most widely employed p-dopants for hole-transporting materials (HTMs) within the state-of-the-art perovskite solar cells (PSCs). The hygroscopicity and migration of these dopants, however, lead to devices with limited stability. To solve this problem, we report here on a diphenyl iodide cation and pentafluorophenyl boric acid anion-based dopant (DIC-PBA) with an oriented interfacial dipole moment as an alternative to Li-TFSI/t-BP. Theoretical and experimental data reveal that DIC-PBA exhibits deep doping of poly[bis(4-phenyl)(2,4,6-triMethylphenyl)aMine] (PTAA) and also creates p-doping of perovskite surface, which originates from ionic interactions-derived dipole arrangement that yields fast interfacial charge transport. The improved intrinsic stability of PSCs originates from the inhibition of dipole moment degeneration on the perovskite surface. Devices prepared with DIC-PBA yielded high efficiency of 22.86%, and the modules (aperture area: 33.2 cm2) efficiency reached 19.13%. Importantly, the storage stability also significantly improved exceeding to 90% after aging 1,200 h under air ambient.

Cucurbit[8]uril-controlled [2 + 2] photodimerization of styrylpyridinium molecule

Complexation of ( E )-4-(4-(1-methyl-pyridinium)styryl)-1-methyl-pyridinium chloride (SMP) guest and cucurbit[8]uril (CB[8]) host depending on the host-guest interactions which was characterized by 1 H NMR spectroscopy, electronic absorption, isothermal titration calorimetry, high-resolution electrospray mass spectrum and fluorescence spectroscopy. What’s more interesting is that the styryl units in supramolecular complexes can more easily undergo [2 + 2] photodimerization under the promotion of macrocyclic CB[8] when irradiated with visible light. • Complexation of SMP and CB[8] depending on the host-guest interaction. • The styryl group of SMP is located in the cavity of CB[8], resulting in a highly stable inclusion complex SMP@CB[8] with a host-guest binding ratio of 2:1. • The styryl units of supramolecular complexes can more easily undergo [2 + 2] photodimerization under the promotion of CB[8] when irradiated with visible light. he interaction of ( E )-4-(4-(1-methyl-pyridinium)styryl)-1-methyl-pyridinium chloride (SMP) guest, with cucurbit[8]uril (CB[8]) host was characterized by 1 H NMR spectroscopy, electronic absorption, isothermal titration calorimetry (ITC), high-resolution electrospray mass spectrum and fluorescence spectroscopy. Experimental data indicated that the styryl group of SMP resides within the cavity of CB[8] in aqueous solution, generating a highly stable inclusion complex SMP@CB[8] with a host-guest binding ratio of 1:2. Isothermal titration calorimetry experiments showed that the complexation of the SMP guest with CB[8] were enthalpy and entropy driven, which benefits from ion dipole interactions between the guest SMP and the host CB[8]. What’s more interesting is that the styryl units of supramolecular complexes can more easily undergo [2 + 2] photodimerization under the promotion of macrocyclic CB[8] when irradiated with visible light.

Kinetic and mechanistic study of oxidation of phenyl thiourea by pyridinium chlorochromate in aqueous DMF medium

Oxidation of Phenyl Thiourea by pyridinium chlorochromate in aqueous DMF medium, containing perchloric acid has been studied. The rate of reaction was found to be of first order with respect to [PCC], [PTU] and [H+]. The increase in the rate of oxidation with increase in acidity indicates the involvement of a protonated chromium(VI) species in the rate-determining step. the rate of reaction increased with increase in dielectric constant of the reaction medium., which indicates that there is involvement of an ion–dipole type of interaction in the rate-determining step. The activation parameters have been evaluated. On the basis of the experimental findings, a suitable mechanism and rate law has been proposed.

Structure and Rheology of Poly(vinylidene difluoride-co-hexafluoropropylene) in an Ionic Liquid: The Solvent Behaves as a Weak Cross-Linker through Ion–Dipole Interaction

Mixtures of poly(vinylidene difluoride-co-hexafluoropropylene) (PVDF-HFP) and ionic liquids (IL) are known to form flexible, self-healing, and ion-conductive materials that are often referred to as polymer–gel electrolytes. The ion–dipole interaction occurs between PVDF-HFP and the cation; that is, the IL acts not only as a solvent but also as a transient cross-linker to form the network structure, and the density of the binding site (C–F dipole) along the polymer chain is quite high. While the practical importance of this type of polymer/IL has become evident, the fundamental solution properties of these types of polymers have not been clearly understood. Here, we studied the structure and viscoelastic properties of the PVDF-HFP/IL system using infrared spectroscopy, wide- and small-angle X-ray scattering (WAXS/SAXS), and steady-state and oscillatory shear rheology. The polymer network structure was found to maintain the geometrically similar figure ξ ∼ ϕ1/3, where ξ and ϕ denote the correlation length (length of the network strand) and volume fraction of the polymer, respectively. In addition, with an increase in ϕ, the larger-scale structure changed from a mass fractal to a surface fractal morphology at the overlap concentration. The dynamics of this polymer network system is presumed to be governed by the relaxation through repeated association–dissociation processes with the cation. The specific viscosity followed ηsp ∼ ϕ8 in the concentrated solution of PVDF-HFP. The viscometry results indicated that the apparent binding energy increased with ϕ; that is, the C–F dipoles were cooperatively bound to each other via the cations.

Front Cover: Cucurbit[7]uril Inhibits Islet Amyloid Polypeptide Aggregation by Targeting N Terminus Hot Segments and Attenuates Cytotoxicity (Chem. Eur. J. 38/2022)

Islet amyloid polypeptide (IAPP) self-assembly is responsible for the decline of pancreatic β-cells, which is implicated in type II diabetes. The macrocyclic host, cucurbit[7]uril (CB[7]), effectively inhibits IAPP aggregation through ion–dipole and hydrophobic interactions with different residues of the monomeric peptide in its primary random-coil conformation. Most importantly, CB[7] rescues rat insulinoma cells (a robust pancreatic β-cell model) from IAPP-assembly-associated cytotoxicity. More information can be found in the Research Article by D. Maity, A. D. Hamilton, and co-workers (DOI: 10.1002/chem.202200456).

Cucurbit[6]uril-based supramolecular frameworks formed through outer surface interactions and application for iodine adsorption

The interaction between the outer surface of cucurbit[6]uril (Q[6]) and methyl triphenyl phosphorus iodide (MTPI) has been studied in the presence of [CdCl4]2-. The MTPI is connected to four neighboring Q[6]s through weak interactions such as C-H···π and C-H···O, whilst the [CdCl4]2- is connected with the portal carbonyl oxygen, glycoside urea methylene and a bridging methylene of a Q[6] molecule via ion–dipole interactions. These interactions were evident from a single crystal X-ray diffraction study of Q[6]-MTPI-[CdCl4]2-. Furthermore, this complex exhibits a porous structure, which can be described as a Q[6]-based supramolecular framework (QSF), and its ability to adsorb iodine was also investigated.

Intermolecular/intramolecular interactions for high-performance organic batteries

<p indent="0mm">The development of new materials for lithium-ion batteries and similar next-generation secondary batteries is one of the hottest topics in the field of materials science. Organic electrode materials have attracted much attention because of their rich resources, structural designability, molecular level controllability and flexibility. Different from traditional inorganic electrode materials, organic compounds have various intermolecular/intramolecular interactions, which undoubtedly could affect the electrochemical performances of organic batteries. This review mainly outlined our efforts to develop high-performance organic batteries through rational molecular design to adjust the intermolecular or intramolecular interactions, mainly including the hydrogen bonding, π–π, ion–ion, ion–dipole as well as the dipole–dipole interactions, so as to solve the key challenges in organic electrode materials. And some prospects are provided for the development of high-performance organic energy-storage materials in the future.

Loose nanofiltration membranes functionalized with in situ-synthesized metal organic framework for water treatment

In this study, modified loose nanofiltration membranes were prepared by in-situ decoration with Zeolitic Imidazolate Framework-7 (ZIF-7) on the surface of porous polyethersulfone substrates functionalized with co-deposited sulfobetaine methacrylate (SBMA) zwitterion (ZW) and polydopamine (PDA). With the aid of ZW/PDA active layer co-deposition under mild conditions, ZIF-7 metal organic framework (MOF) nanocrystals were successfully formed and anchored onto the membrane surface via both non-covalent and covalent bonds to simultaneously achieve the desired selectivity and productivity of the loose nanofiltration membranes. The characterization results confirmed the successful deposition of the ZW/PDA active layer and the consequent decoration with ZIF-7 nanocrystals. The average water contact angle decreased notably from 81.4 to 51.43° upon the formation of ZIF-7. This membrane showed high rejection (∼99.9%) of methyl blue and Congo red dyes and high water flux with dye solutions (around 40 L m−2h−1) at a very low applied pressure of 1.5 bar. Moreover, the filtration experiments revealed that functionalized membranes exhibited a significant reduction in fouling and biofouling propensity. Notably, the MOF-SBMA/PDA membrane displayed favorable antifouling behavior associated with a significant ability to recover flux upon simple physical cleaning. The combination of these two properties is possibly the most promising feature of the membrane proposed in this study.

Influence of zwitterionic structure design on mixed matrix membrane stability, hydrophilicity, and fouling resistance: A computational study

Zwitterion-based mixed matrix membranes (MMMs) with designed characteristics of enhanced water flux, selectivity, and fouling mitigation have emerged as a new class of advanced membranes for oilsands process-affected wastewater (OSPW) treatment. Zwitterions (ZW) characterized by super-hydrophilicity and excellent fouling resistance have gained increasing attention in membrane modification research. In general, zwitterion properties are determined by the chemistry and structural properties of its constituents, including the polymer backbone, charged moieties, spacers, as well as molecular configuration. This study used molecular dynamics simulation (MDS) to investigate the effects of polymer backbone (PB), spacer length (SL), and spacer chemistry (SC) on ZW-based MMM properties such as stability, hydrophilicity, and oil-antifouling potentiality. Membrane performance was also assessed at high temperatures (50, 70, and 90 °C. The results suggest PB, SL, and SC all influence the resultant MMM performance, with SL being the most impactful structural parameter on stability and hydrophilicity. Variation of SL was suspected to alter the ionic association and partial charges of zwitterionic moieties, which affect their ability to interact with the polymer network and water molecules. Spacer chemistry (i.e., hydroxyl (-OH) groups) can initiate self-association between zwitterionic charged groups having short SL, lessening their inter-molecular networking ability. However, for ZWs with long SL, the presence of hydroxyl groups on the spacer can result in the formation of hydrogen bonds and/or electrostatic interactions with other ZW molecules and polyvinylidene difluoride (PVDF) polymer chains or water molecules, improving membrane stability and hydrophilicity. High temperatures reduced membrane stability but to a lesser extent for MMMs compared to unmodified PVDF membrane. While temperature greatly influenced membrane hydrophilicity, the impacts were membrane-specific. The oil-fouling propensity of pristine PVDF membrane increased with temperature but of MMMs appeared stable across the temperature range studied.

Friction-induced supramolecular nanovalves for the potential treatment of osteoarthritis

Owing to the overuse of rough articular cartilage, it increases the friction of joint and further leads to inflammation in joint cavities. However, the pathological changes also bring a new opportunity to achieve the treatment of osteoarthritis (OA). The increasing friction from damaged articular cartilage can convert more mechanical energy to heat. The higher localized temperature can reduce supramolecular interactions in general. Therefore, friction becomes another new activation to operate nanovalve systems for the targeting treatment of OA. Here, we designed and prepared a friction-induced nanovalve system constructed with β-cyclodextrins (β-CD)-modified mesoporous silica nanoparticles (MSN). Besides, a copolymer containing two components – guest molecules (adamantane, AD) and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) – has been self-assembled on the surface of β-CD-modified MSN (MSN-CD) by supramolecular host–guest interactions. In this design, the charged PMPC on the MSN surface can form a dense hydration layer by ion–dipole interactions, switch the friction from surfaces to water molecules to achieve hydration lubrication, and sharply reduce the coefficient of friction (COF). Besides, the higher localized temperature from the mechanical conversion can weaken the supramolecular host–guest interactions and turn on the nanovalves to accomplish the targeted release near rough articular cartilage of OA. Even when PMPC is peeled off, the hydrophilic surface of β-CD on MSN surface can still perform the acceptable lubricating properties. The following testings of cytotoxicity by CCK-8 and live/dead staining indicated the excellent biocompatibility. Further analysis of protein expression levels has also shown the potential application in OA.

PEGylated and zwitterated silica nanoparticles as doxorubicin carriers applied in a breast cancer cell line: Effects on protein corona formation

Nanomaterials exposed to biological fluids form protein coronas on their surfaces, changing their original properties. Surface functionalization with nonfouling moieties is a strategy to synthesize silica nanoparticles (SiNPs) with the ability to hinder protein corona formation. We report a simple poly(ethylene glycol) (PEG) and zwitterionic (ZWT)-based surface modification method to prepare doxorubicin-loaded SiNPs to avoid protein corona formation in breast cancer cells. Drug-loaded SiNPs were characterized in terms of particle size, charge, and drug loading content. A comparison of the stability between PEG and ZWT on SiNP surfaces was performed at 25 °C and 37 °C in a high salt solution using turbidimetry. At 37 °C, the PEGylated SiNPs showed aggregation. In contrast, under the same conditions, zwitterated SiNPs did not show aggregation. Both PEG and ZWTSiNP savoided protein adsorption in the presence of increasing concentrations of bovine serum albumin (BSA). In vitro cell experiments demonstrated that both functionalization approaches (SiNPs-PEG and SiNPs-ZWT) improved biocompatibility in the breast cancer cell line MCF-7compared to SiNPs. The antitumour effects of doxorubicin-loaded SiNPs were evaluated via red neutral cell uptake and annexin V assays, and the results demonstrated that surface functionalization plays an important role in the cytotoxic profile of these systems, with SiNPs-DOX-PEG and SiNPs-DOX-ZWT exhibiting a superior cytotoxic effect compared to SiNPs-DOX.

Nonvolatile, stretchable and adhesive ionogel fiber sensor designed for extreme environments

Stretchable conductive sensors based on iontronics are key components for next generation sensing systems in wearable devices or soft robots. Considering the narrow working temperature range of hydrogels-based ionic conductors, ionogel with inherent non-volatility and survivability over a wide temperature range, is proposed to prepare gel fiber-based sensor, via exceedingly simple mold method. Zwitterionic monomer [2-(Methacryloyloxy) ethyl] dimethyl-(3-sulfopropyl) (SBMA) and acrylamide (AM) were selected to construct the crosslinked ionogel networks. The ion–dipole, dipole–dipole interactions and interchain hydrogen bonds introduced in the ionogel fiber (IGF) system, simultaneously improve the gel strength and endow the IGF with distinctive properties. The resultant IGF exhibits unique self-adhesiveness, excellent transparency, tunable mechanical properties and ultrahigh stability in various extreme environments. Moreover, as a strain sensor, the as-fabricated IGF is characteristic by outstanding sensitivity with a gauge factor (GF) of 6.20, low detection threshold (0.5% strain) and high durability (1000 cycles at 100% strain). The sensor works well in harsh environments, exhibiting an enlarged working temperature range (–80 ∼ 150 °C) and high tolerance under vacuum (1.325 kPa). We anticipate this IGF-based sensor to make up for the vacancy of flexible sensors in extreme circumstances, thus expanding more application scenarios.