Phosphonate Groups Research Articles

Anhydrous proton-conducting material consisting of basic protein protamine

• Protein composite material indicates anhydrous proton conductivity. • Basic protein protamine and acid molecule form an acid-base composite. • Protamine is used as an energy material, such as anhydrous proton conductor. Protamine, one of the nucleoproteins, is contained in the sperm of fishes and is a linear polypeptide with many arginine (Arg) residues. The basic polypeptide chain can behave as the proton acceptor site in the acid-base composite material. Therefore, we prepared the composite material by the mixing of the basic protein, protamine, and the acidic molecule, methanediphosphonic acid (MP). The protamine-MP composite materials formed the acid-base complex by the electrostatic interaction between the protonated guanidino group in Arg residue and the deprotonated phosphonic acid group in the MP molecule. In addition, the protamine-MP composite material showed the anhydrous proton conductivity of 9.1 × 10 −4 S cm −1 at 160 °C in the flowing dry nitrogen. The proton conducting mechanism in the protamine-MP composite material depended on the proton transfer to the proton defect site in the MP molecule without the need of diffusible molecules, such as the oxonium ion.

Phytic acid-decorated porous organic polymer for uranium extraction under highly acidic conditions

Although various kinds of adsorbents have good uranium adsorption capacity, they still meet the challenge in capturing uranium under highly acidic condition. Therefore, efficiently extracting uranium under strong acidic condition become the pursuit of researchers. In this study, a new phytic acid decorated porous organic polymers (POPs) named MA-U-PA was prepared by synthesizing a organic framework (MA-U) using melamine and uracil and with subsequent phytic acid modification. The results showed that the excellent stability of the prepared organic framework and strong uranium chelating ability of phytic acid endowed the as-prepared material being an excellent adsorbent under strong acidic condition. The adsorption capacity achieved 106.7 mg·g -1 at the pH of 1 which was much higher than that of MA-U and most of other adsorbents. The study of modification mechanism confirmed that the hydrogen bonds interaction of phytic acid with MA-U lead to the successful modification. In addition, the phosphonate groups of PA was mainly the active groups chelated with uranium. Moreover, the uranium adsorption process of MA-U-PA was in accordance with the pseudo-second-order kinetic and Langmuir isothermal model. The newly prepared phytic acid decorated porous organic material could achieve efficient uranium capturing from highly acidic nuclear wastewater. • The raw materials were melamine, uracil and phytic acid which were relatively green and nontoxic. • The organic framework made the adsorbent stable and phosphoric groups on the surface endowed the adsorbent capturing uranium efficiently under strong acidic conditions. • The uranium adsorption capacity of MA-U-PA attained to 106.7 mg·g -1 under pH of 1, higher than most of other adsorbents.

Mesoporous Silica Nanoparticles Improve Oral Delivery of Antitubercular Bicyclic Nitroimidazoles.

Pretomanid and MCC7433, a novel nitroimidazopyrazinone analog, are promising antitubercular agents that belong to the bicyclic nitroimidazole family. Despite possessing high cell permeability, they suffer from poor aqueous solubility and require specialized formulations in order to be orally bioavailable. To address this limitation, we investigated the use of mesoporous silica nanoparticles (MCM-41) as drug carriers. MCM-41 nanoparticles were synthesized using a sol–gel method, and their surface was further modified with amine and phosphonate groups. A simple rotary evaporation method was used to incorporate the compounds of interest into the nanoparticles, leading to a high encapsulation efficiency of ≥86% with ∼10% loading (w/w). An overall significant improvement of solubility was also observed, and the pharmacological activity of pretomanid and MCC7433 was fully retained when tested in vitro against Mycobacterium tuberculosis using these nanocarriers. Amino-functionalized MCM-41 nanoparticles were found to enhance the systemic exposure of MCC7433 in mice (1.3-fold higher Cmax) compared to MCC7433 alone. The current work highlights the potential of using nanoparticles such as mesoporous silica as a carrier for oral delivery of poorly soluble antibacterial agents against tuberculosis.

Phosphonate functionalized N-heterocyclic carbene Pd(II) complexes as efficient catalysts for Suzuki-Miyaura cross coupling reaction

A N-heterocyclic carbene (NHC) ligand, L1 bearing a pendant phosphonate ester group is used to prepare two new NHC-Pd(II) complexes, [Pd(L1)2I2] (1) and [Pd(L1)(py)I2] (2) (py = pyridine). Hydrolysis of phosphonate ester group in 2 results another Pd(II)-NHC complex, [Pd(L2)(py)I2] (3) where a phosphonic acid group is attached to the NHC ligand L2. All the three complexes are characterized by analytical and spectroscopic studies while the molecular structures of 1-2 are also determined by single crystal X-ray diffraction measurement. The catalytic efficacies of 1-3 in Suzuki-Miyaura cross coupling reactions of aryl halides and aryl boronic acid are investigated. DFT calculations were performed to decipher the role phosphonate ester or phosphonic acid substituents on the catalytic efficacy.

The utilization of 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) as a novel sphalerite depressant in the selective flotation of galena from sphalerite

In this work, 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) was explored as a novel sphalerite depressant in the selective flotation of galena from sphalerite. The separation performances were investigated by single and synthetic flotation tests. The depression mechanism was examined by Fourier Transform Infrared spectroscopy (FTIR), zeta potential and X-ray Photoelectron Spectroscopy (XPS) analysis. The flotation test results showed that PBTCA was an effective sphalerite depressant with good selectivity at broad pH range, which could achieve satisfactory separation results. Zeta potential and FTIR results indicated that PBTCA was more prone to adsorb on sphalerite surface than that of galena. In addition, SIBX could replace adsorbed PBTCA on the galena surface while it was impossible to substitute that on the sphalerite surface, which rendered sphalerite surface hydrophilic and enlarged the floatability difference. XPS analysis manifested that PBTCA was adsorbed on sphalerite surface through the strong complexation between carboxyl, phosphonic acid groups and Zn sites on sphalerite surface, forming C-O-Zn or P-O-Zn bond.

Hybrid Quinolinyl Phosphonates as Heterocyclic Carboxylate Isosteres: Synthesis and Biological Evaluation against Topoisomerase 1B (TOP1B).

This work describes, for the first time, the synthesis of dialkyl (2-arylquinolin-8-yl)phosphonate derivatives. The preparation was carried out through a direct and simple process as a multicomponent Povarov reaction of aminophenylphosphonates, aldehydes, and styrenes and subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or, alternatively, by a cycloaddition reaction between phosphonate aldimines and acetylenes. Based on phosphonate group structural characteristics, considered as phosphorous isosteres of carboxylic heterocycles, they may present interesting biological properties related to cell proliferation. In the current report, a new series of dialkyl (2-arylquinolin-8-yl)phosphonates have been synthesized and their antiproliferative effect evaluated on different human cancer and embryonic cells, as well as on Leishmania infantum parasites, a eukaryotic protist responsible for visceral leishmaniasis. Thereby, the antitumor effect was assessed in human lung adenocarcinoma cells (A549), human ovarian carcinoma cells (SKOV3), and human embryonic kidney cells (HEK293) versus the non-cancerous lung fibroblasts cell line (MRC5). On the other hand, the antileishmanial activity was tested against both stages of L. infantum cell cycle, namely free-living promastigotes and intramacrophage amastigotes, using a primary culture of Balb/c splenocytes to calculate the selectivity index. Besides the antiproliferative and antileishmanial capacities, their behavior as topoisomerase 1B inhibitors has been evaluated as a possible mechanism of action.

Aggregation of Bifunctional Extractants Used for Uranium(VI) Separation.

DEHCNPB (butyl-N,N-di(2-ethylhexyl)carbamoyl-nonylphosphonate) is an amido-phosphonic acid that has remarkable properties for the separation of uranium from wet phosphoric acid. Despite previous studies, a detailed description of the DEHCNPB organic solutions at the supramolecular and molecular scales is missing. In the present work, we use classical Molecular Dynamics (MD) combined with SANS and SAXS experimental data in order to describe the aggregation of the bifunctional extractant DEHCNPB as well as the speciation of uranium(VI) in such systems. We provide a fine description of the molecular species in the organic solution and of the interactions within the aggregates formed, shedding light on solvent extraction mechanisms. Without uranium, the organic phase is highly composed of dimers and trimers H-bonded through phosphonate functions and without water molecules. With uranium, two to three extractant molecules coordinate directly the uranyl cation by their phosphonate groups. Uranyl is not fully dehydrated in this organic solution, and the amide groups of the extractants are found to form H-bonds with the water molecules bound to uranyl. These H-bond networks around the metallic cation stabilize the complexes and facilitate the extraction. These results underline the importance of considering weak interactions in the understanding of extraction processes and demonstrate how molecular simulations provide essential insights into such complex organic phase chemistry with a high number of species.

Co‐Evaporated Formamidinium Lead Iodide Based Perovskites with 1000 h Constant Stability for Fully Textured Monolithic Perovskite/Silicon Tandem Solar Cells

AbstractFormamidinium iodide (FAI) based perovskite absorbers have been shown to be ideal candidates for highly efficient and operationally stable perovskite solar cells (PSC). A major challenge for formamidinium lead iodide (FAPbI3) is to suppress the phase transition from the photoactive black phase into yellow nonperovskite δ‐phase. Several approaches to stabilize the black phase have been developed for solution‐based perovskites, whereas so far, vacuum‐deposited FAPbI3 has rarely been reported. This study demonstrates the preparation of FAPbI3 by co‐evaporation and discusses the influence of the subjacent hole transporting layer (HTL) on its phase stability. By using FAI excess in the evaporation process in combination with phosphonic acids groups from the HTL, the black perovskite phase is stabilized at room temperature. Further addition of 32–59% methylammonium iodide (MAI) during the co‐evaporation process leads to good absorption properties and high PSC efficiencies of 20.4%. In addition, excellent stability is achieved for optimized MAI to FAI ratios, maintaining 100% of the initial PSC performance after 1000 h under constant operation. This highly stable perovskite composition enables the first monolithic fully textured perovskite/silicon tandem solar cells with co‐evaporated perovskite absorbers. Due to the conformally covered pyramid texture, these tandem cells show minimal reflection losses and reach an efficiency of 24.6%.

A turn-on fluorescence sensor based on Cu2+ modulated DNA-templated silver nanoclusters for glyphosate detection and mechanism investigation

The abuse application of glyphosate can result in a potential hazard for environment and human, however its ultrasensitive detection remains challenging. Herein, a Cu2+ modulated DNA-templated silver nanoclusters (DNA-AgNCs) sensor was constructed to sensitively determine glyphosate based on the turn-on fluorescence strategy. The fluorescence quenching of DNA-AgNCs occurred with the existence of Cu2+. Upon the presence of glyphosate, the functional groups on the surface of glyphosate could chelate with Cu2+, following the fluorescence recovery of DNA-AgNCs. Through the stoichiometric methods, we unveil that Cu2+-trigged fluorescence quenching mode is a combination of static and dynamic quenching with the static mode being predominant. In DNA-AgNCs/Cu2+ system, the carboxylate, amine, and phosphonate groups of glyphosate interact with Cu2+ through chelation, in which the carboxylate oxygen, the phosphonate oxygen atoms, and the monoprotonated secondary amine nitrogen atom and Cu2+ form chelate rings. This fluorescence sensor showed a desired linearity of glyphosate analysis under the optimum conditions, ranging from 15 to 100 μg/L with a low detection down to 5 μg/L. Moreover, the proposed sensor was successfully utilized to measure glyphosate in real samples, indicating a promising application in pesticide residues detection.

Development of a fluorescent probe for detecting Al3+ in cooked wheaten food based on phosphonic acid group functionalized polythiophene derivatives.

As an unnecessary trace element, the content of aluminium in biological systems should be strictly controlled. Therefore, it was necessary to develop a convenient method for detection of aluminium ions. In this study, a fluorescent probe based on polythiophene derivatives was developed and used to detect Al3+ in Chinese traditional pasta. The fluorescence of this probe showed a significant decrease in hexamethylenetetramine-HCl buffer solution (pH 5) when Al3+ was present. In addition, the probe exhibited good sensitivity and selectivity to Al3+ over other metal ions when EDTA was used as the masking agent. Fluorescence intensity had a good linear relationship with the Al3+ concentration in the range 0.1-10 μM and the limit of detection for Al3+ was 39 nM. Furthermore, the probe was successfully applied to detect Al3+ in food samples and the results were consistent with ICP-AES.

Reusable selective sensing-substrate for ultrasensitive and rapid detection of uranium radioisotopes

An analytical method based on a fabricated analytical disc was developed using a phosphonate-immobilized quartz substrate for the rapid analysis of uranium. Phosphonate groups selectively adsorb uranium dissolved in a solution through the formation of stable complexes. The uranium concentration and isotopic ratios in the sample can rapidly be determined by measuring the radioactivity of the adsorbed uranium on the analytical disc using alpha-particle spectrometry. The chemical structure and elemental composition of the fabricated disc were analyzed by XPS, and the adsorption properties were evaluated as functions of pH of a sample solution, reaction time, and adsorbate concentration, as well as reusability and selectivity, using alpha-particle spectrometry, ICP-OES, and ICP-MS. An analytical method was developed based on these properties and validated with prepared uranium solutions by assessing the chemical recovery yield, relative error, and relative standard deviation. The developed method is expected to be used for on-the-spot uranium analysis.

(Bis)phosphonic Acid-Functionalized Poly(ethyleneimine)–Poly(amido amine)s for Selective In Vitro Transfection of Osteosarcoma Cells

Osteosarcoma is aggressive bone cancer, whose treatment has not changed significantly for the past few decades. Although gene therapy methods have emerged as potential treatment routes, the need for efficient and nontoxic gene delivery systems targeting osteosarcoma cells remains a challenge. High-molecular-weight poly(ethyleneimine)s (PEIs) are used as universal transfection agents; however, they cause significant cytotoxicity. On the other hand, poly(amido amine)s (PAAs) are biocompatible, biodegradable polymers with promising transfection efficiency, which should be improved further. In this paper, we combined low-molecular-weight branched PEI (1800 Da) and PAA macromers functionalized with various amounts of (bis)phosphonic acid groups and pentanol (via 5-amino-1-pentanol (AP)). The (bis)phosphonic acid groups on these polymers (PAEIs) are intended to facilitate bone targeting. The molecular weights of the PAEI polymers were between 2600 and 8600 g/mol. Their cytotoxicities and green fluorescence protein (GFP) transfection efficiencies were tested on an osteosarcoma cell line (U-2 OS cells), which is challenging to transfect, and healthy muscle cells (C2C12). Both the cytotoxicity and transfection efficiency of PAEIs were affected by the phosphonic acid (via APA, 2-aminoethyl phosphonic acid) or bisphosphonic acid (via ALE, sodium alendronate) content of the polymers. PAEIs are more cytocompatible than both linear and branched 25 kDa PEI. ALE-containing PAEIs provided better transfection than APA-containing ones. The most efficient PAEI polymer, containing a 0.7:0.3 AP/ALE ratio, displayed a transfection efficiency that was five times higher than that of 25 kDa PEI with dramatically better cytocompatibility. This is comparable to FuGENE, but PAEI is more advantageous in selective transfection of the U-2 OS. This set of polymers may be promising candidates for targeted gene therapy of osteosarcoma.

Effect of Functional Phosphonic Groups Grafted on the Silica Surface on the Properties of Hybrid Membranes Based on Polybenzimidazole PBI-O-PhT

Effect of Functional Phosphonic Groups Grafted on the Silica Surface on the Properties of Hybrid Membranes Based on Polybenzimidazole PBI-O-PhT

Hexagonal Cylinder Mesoporous Sorbent for Separation of Uranium Ions from Nitrate Media

AbstractThe synthesis of mesoporous silica monoliths‐based phosphonate groups (SiO2‐DPTS) through immobilization of diethylphosphatoethyltriethoxysilane using the post‐grafting approach to be applied as a sensitive sorbent for selective separation of U(IV) ions from aqueous solutions is described. The designed SiO2‐DPTS sorbent was characterized by Fourier transform infrared, scanning electron and high‐resolution transmission electron microscopy, scanning transmission electron microscopy/energy‐dispersive X‐ray spectroscopy, N2 adsorption‐desorption, and elemental analysis. The adsorption process was studied under different experimental conditions of pH, concentration, and time. The mechanism of interaction of SiO2‐DPTS with U(VI) ions was explored and supported by density functional theory (DFT) calculations. This synthesized sorbent allows highly efficient extraction of U(IV) ions from uranyl leach liquor.

N-methylene phosphonic chitosan aerogels for efficient capture of Cu2+ and Pb2+ from aqueous environment

In this paper, N-methylene phosphonic acid chitosan (NPCS-PEI) was synthesized from chitosan, phosphorous acid, formaldehyde and hyperbranched polyethyleneimine (PEI), and Cu2+ and Pb2+ removal performance was examined in aqueous solution. NPCS-PEI exhibited three-dimensional porous architectures, with a specific surface area of 490.61 m2/g. The effects of pH, initial concentration, adsorption time, temperature and ionic strength on the adsorption capacity were investigated. The adsorption kinetics indicated that Cu2+ and Pb2+ adsorption onto NPCS-PEI follows a pseudo-second-order model. The adsorption isotherms agree well with the Langmuir isotherm model, and the maximum adsorption capacities of Cu2+ and Pb2+ on the NPCS-PEI are approximately 276.12 and 645.16 mg/g, respectively. The adsorption efficiency of NPCS-PEI remained above 85% after 5 adsorption-desorption successive cycles. Moreover, the NPCS-PEI aerogels had selective adsorption toward Cu2+. The FTIR and XPS analysis proved that amino, hydroxyl, and phosphonic acid groups were involved in the chelation with metal ions.

Recovery of lanthanum, praseodymium and samarium by adsorption using magnetic nanoparticles functionalized with a phosphonic group

In this work, the synthesis and application of a promising magnetic adsorbent for the recovery of lanthanum, praseodymium, and samarium was studied. To obtain the magnetic adsorbent, magnetite nanoparticles were functionalized with a phosphonic acid group (PA-MNPs) by an efficient and reproducible method. Based on HR-TEM analysis, PA-MNPs present an average diameter of 6.8 nm, have a spherical shape, and a certain degree of agglomeration at approximately 20 to 40 nm. The nanoparticles' magnetic saturation was found to be approximately 55 emu/g, enough to provoke their complete separation from an aqueous raffinate using a common magnet. The XPS and FTIR analyses provided evidence for a phosphonic acid group on the surface of the magnetite nanoparticles. The effect of the pH and the initial concentration of lanthanide ions in the aqueous feed solution and the adsorbent dose on REE adsorption was studied. Maximum lanthanide ion loading capacities in the range of 20–24 mg lanthanide/g adsorbent were measured close to pH 4 (contact time: 5 min.; mass of adsorbent: 200 mg). The PA-MNPs adsorbent presented high mechanical and chemical stability in aqueous solutions with initial pH between 3 and 7. The more efficient desorption (75–100%) of lanthanide ions from the adsorbent was achieved using H2SO4 0.1 M solution. The feasibility of regenerating and reusing functionalized magnetic nanoparticles in five cycles of adsorption/desorption was verified. Freundlich and Langmuir adsorption isotherms fit the experimental equilibrium data well, which would be indicating that the adsorption process would be ruled by a hybrid model. The results of kinetic experiments were well explained by a pseudosecond-order kinetic model, and a very fast initial adsorption rate was observed.

A molecular dynamics study of a fully zwitterionic copolymer/ionic liquid-based electrolyte: Li+ transport mechanisms and ionic interactions.

The development of polymer electrolytes (PEs) is crucial for advancing safe, high-energy density batteries, such as lithium-metal and other beyond lithium-ion chemistries. However, reaching the optimum balance between mechanical stiffness and ionic conductivity is not a straightforward task. Zwitterionic (ZI) gel electrolytes comprising lithium salt and ionic liquid (IL) solutions within a fully ZI polymer network can, in this context, provide useful properties. Although such materials have shown compatibility with lithium metal in batteries, several fundamental structure-dynamic relationships regarding ionic transport and the Li+ coordination environment remain unclear. To better resolve such issues, molecular dynamics simulations were carried out for two IL-based electrolyte systems, N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([BMP][TFSI]) with 1M LiTFSI salt and a ZI gel electrolyte containing the IL and a ZI copolymer: poly(2-methacryloyloxyethyl phosphorylcholine-co-sulfobetaine vinylimidazole), poly(MPC-co-SBVI). The addition of ZI polymer decreases the [TFSI]- -[Li]+ interactions and increases the IL ion diffusivities, and consequently, the overall ZI gel ionic conductivity. The structural analyses showed a large preference for lithium-ion interactions with the polymer phosphonate groups, while the [TFSI]- anions interact directly with the sulfonate group and the [BMP]+ cations only display secondary interactions with the polymer. In contrast to previous experimental data on the same system, the simulated transference numbers showed smaller [Li]+ contributions to the overall ionic conductivities, mainly due to negatively charged lithium aggregates and the strong lithium-ion interactions in the systems.

Heterometallic uranyl-organic frameworks incorporating manganese and copper: Structures, ammonia sorption and magnetic properties

Incorporating transition metal ions into uranyl phosphonate frameworks can bring not only new structure types but also interesting physical or chemical properties. Herein we report two heterometallic uranyl carboxyphenylphosphonates, namely, [Cu2(UO2)3(2-pmbH)2(2-pmb)2(H2O)4]·2H2O (1) and [Mn3(UO2)6(2-pmb)6(H2O)8]·10H2O (2) [2-pmbH3 = 2-(phosphonomethyl)benzoic acid]. Compound 1 shows a two-dimensional layered structure in which uranyl-PO3 chains are linked by {Cu2O2} dimers. Within the uranyl-PO3 chain, {UO6} tetragonal bipyramids and edge-sharing dimers of {UO7} pentagonal bipyramids are connected by edge-sharing {PO3C} tetrahedra. Compound 2 possesses a unique 3D open framework structure, where the Mn-layers are pillared by uranyl-PO3 chains. The uranyl-PO3 chain in 2 is very different from that in 1, which contains trimers of edge-sharing {UO7} and {UO8} polyhedra and {PO3C} linkages. While the Mn-layer consists of chains of {MnO6} octahedra bridged alternatively by carboxylate and phosphonate groups, which are inter-connected by organic moieties of 2-pmb3-. The thermally activated sample of 2 displays strong adsorption capability toward NH3. Magnetic studies revealed dominant antiferromagnetic interactions between the metal centers in both compounds.

Enhancement of flame retardancy and physical property for poly(vinyl chloride) having renewable cardanol-based self-polymerizable phosphonate under heat treatment process

Considering the drawbacks of conventional plasticizers used for poly(vinyl chloride) (PVC), it is imperative to develop bio-based additives. Herein, bis(cardanyl) phenylphosphonate (CP), which is not only a flame retardant but also a plasticizer for PVC, was designed and synthesized from cardanol. The flame retardancy and flexibility of PVC improved with an increase in the CP content (wt%) because of the presence of the phosphonate group and long alkyl chain of CP, respectively. Meanwhile, we found that CP can be self-polymerized by heat treatment and that the cross-linked network of CP leads to an additional enhancement in the flame retardancy of PVC by inducing anti-dripping property and the formation of graphitized char layer. Also, the flexibility of the PVC films was preserved without deteriorating its transparency. CP with self-polymerization properties is a promising candidate to improve the thermal stability, flame retardancy, and flexibility of PVC while maintaining its transparency and migration stability.

A Sustainable Improvement of ω-Bromoalkylphosphonates Synthesis to Access Novel KuQuinones

Owing to the attractiveness of organic phosphonic acids and esters in the pharmacological field and in the functionalization of conductive metal-oxides, the research of effective synthetic protocols is pivotal. Among the others, ω-bromoalkylphosphonates are gaining particular attention because they are useful building blocks for the tailored functionalization of complex organic molecules. Hence, in this work, the optimization of Michaelis–Arbuzov reaction conditions for ω-bromoalkylphosphonates has been performed, to improve process sustainability while maintaining good yields. Synthesized ω-bromoalkylphosphonates have been successfully adopted for the synthesis of new KuQuinone phosphonate esters and, by hydrolysis, phosphonic acid KuQuinone derivatives have been obtained for the first time. Considering the high affinity with metal-oxides, KuQuinones bearing phosphonic acid terminal groups are promising candidates for biomedical and photo(electro)chemical applications.