Disulfonic Acid Disodium Salt Research Articles

A Complex Methodological Approach for the Screening of Efficient and Safe Cobalt Chelators.

Cobalt is an essential trace element, but it can also rarely cause cobalt toxicity due to its release from cobalt-containing medical devices. Currently, there are no approved selective cobalt chelators, which would represent an optimal treatment modality. This study aimed to develop a simple and complex methodological approach for screening potential cobalt chelators and evaluating their potential toxicity. Firstly, a simple spectrophotometric assay employing 1-nitroso-2-naphthol-3,6- disulfonic acid disodium salt (NNDSA) for screening cobalt chelation was standardized at a pathophysiologically relevant range of pH 4.5-7.5. Then, the suitability of the method was verified using four known metal chelators (EDTA, 8-hydroxyquinoline, chloroxine and nitroxoline). As cobalt can catalyse the Fenton reaction, the potential toxicity of cobalt-chelator complexes was also determined by employing a novel HPLC method with coulometric detection. The effect on erythrocyte haemolysis was tested as well. The NNDSA method had high sensitivity enabling the detection of 25-200 nM of cobalt ions depending on pH conditions. Measurements could be carried out in a wide range of wavelengths from 470 to 540 nm. All tested complexes of the selected chelators decreased the rate of the Fenton reaction. Interestingly, chloroxine mixed with cobalt ions caused marked lysis of erythrocytes in contrast to the other compounds. The described complex methodological approach could serve as a simple yet precise tool for evaluating novel, effective and safe cobalt chelators.

Fabrication of high boron removal reverse osmosis membrane with broad industrial application prospect by introducing sulfonate groups through a polyvinyl alcohol coating

The effective removal of boron from water is highly desirable for many chemical processes. Reverse osmosis (RO) membrane technology has been considered to be a competitive technology for boron removal. However, in addition to seawater, RO membrane technology is rarely used in the treatment of other industrial wastewaters containing boron. In this work, a high boron removal RO membrane with broad industrial application prospect was developed. Specifically, sulfonate groups were grafted onto the surface of the RO membrane through the acetal reaction of polyvinyl alcohol (PVA) with benzaldehyde disulfonic acid disodium salt (BADSA Na). In this process, PVA was coated on the membrane surface in advance. The possibility that large complexes can form due to the reaction between PVA and boric acid and the characteristic of the sulfonate group which can decrease the hydrogen bonding sites work together to reduce the rate of boron diffusion, and then a high boron removal rate is achieved. Under seawater conditions, the boron removal rate of the membrane was improved obviously from 85.71% to 91.63%, while a high flux of 44.41 L m−2 h−1 and a high salt rejection of 99.63% was maintained. In addition, the membranes developed were able to maintain excellent boron removal performance in three other industrial water scenarios (geothermal water, nuclear power plant wastewater and oilfield fracturing flowback fluid). Furthermore, the overall performance of the membrane is better than that of other commercially available membranes and existing processes, showing that the membrane developed has a bright promise for various industrial applications.

Membrane properties of sulfonated polytriazoles with molecular branching

AbstractThe incorporation of branching units in the polymer is beneficial in improving many of the polymer properties. This article deals with the synthesis of branched sulfonic acid–based copolytriazoles (PTHPSH‐XX) to prepare freestanding membranes. The copolymers were synthesized by the click reaction of 1,4‐bis(prop‐2‐ynyloxy)benzene, 1,3,5 tris[2‐trifluoromethyl‐4(4‐azidophenyl) phenoxy]benzene (B3), and 4,4′‐diazido‐2,2′‐stilbene disulfonic acid disodium salt. The chemical constructions of the subsequent copolymers were established by Fourier‐transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. The copolymers showed high thermal stability, low water absorption, and outstanding structural robustness in their hydrated state. The presence of branching segments (B3) in the copolymers contributed to improved peroxide radical resistance and proton conductivity (71–192 mS/cm measured at 90°C) in comparison with their linear analogs. In addition, the membranes exhibited reasonably good set of mechanical properties (TS = 71–53 MPa, YM = 2.76–2.33 GPa). The membranes exhibited phase‐separated morphology in their transmission electron microscope images with ionic domains of 20–160 nm.

Effect of Net Charge on DNA-Binding, Protein-Binding and Anticancer Properties of Copper(I) Phosphine-Diimine Complexes

The syntheses of [Cu(PPh3)2(L)]NO3 and [Cu(PPh3)2(L-SO3Na)]NO3 were achieved through the reaction of Cu(PPh3)2NO3 and equimolar amount of the ligands (L = 5,6-diphenyl-3-[2-pyridyl]-1,2,4-triazine; LSO3Na = 5,6-diphenyl-3-[2-pyridyl]-1,2,4-triazine-4,4′-disulfonic acid disodium salt). The complexes were characterized by NMR and IR spectroscopy and mass spectrometry. The compounds exhibit similar absorption and emission spectra, suggesting a similar electronic structure. Ct-DNA binding studies show the strong influence of the net charge as Cu-L (positively charged) is able to bind to ct-DNA while Cu-LSO3Na (negatively charged) is not. The net charge of the complexes affects the thermodynamic and kinetic binding parameters toward human serum albumin. HSA-binding of the complexes was further investigated by molecular docking, revealing different binding sites on the HSA protein as a function of the net charge. The different anticancer activities of the complexes towards ovcar-3 and hope-62 cancer cell lines are suggestive of a role for the overall charge of the complexes. Interaction with the DNA is not the major mechanism for this class of complexes. The overall net charge of the pharmacophore (anticancer agent) should be a key consideration in the design of anticancer metal complexes.

Effects of SLC protein on intestinal HCO<sup>-</sup><sub>3</sub> excretion and acid-base balance of <italic>Gymnocypris przewalskii</italic>

Saline-alkaline water, widely distributed throughout China, is characterized as high salinity and alkalinity, which are the primary factors restricting the survival and growth of aquatic organisms. The physiological mechanisms required for fish to live in fresh water and sea water are well described for several species. Many fishes not only can tolerate, but also can acclimate and adapt to conditions besides conventional fresh water and sea water conditions, specifically saline-alkaline water. When fishes are transferred to saline-alkaline water, there is a transient alkalosis with increased HCO^-₃ or decreased <italic>P</italic>_CO₂ concentrations in the plasma. <italic>Gymnocypris przewalskii</italic> is the most important economic fish in Lake Qinghai, a water body with high salinity and alkalinity. In recent years, the population of <italic>G</italic>. <italic>przewalskii</italic> has sharply declined due to the destruction of spawning habitat, long-term overfishing and the increasing salinity and alkalinity. Thus, researches on the physiological and molecular responses of <italic>G</italic>.<italic>przewalskii</italic> under saline-alkaline conditions are significant for recovering this endangered species. Previous studies had shown that, when <italic>G</italic>. <italic>przewalskii</italic> was acclimated to saline-alkaline water, internal excess HCO^-₃ was not totally excreted by the gills or the kidney. In contrast, it showed that intestinal HCO^-₃ secretion and water absorption might play important roles in the acid-base balance and osmoregulation. In order to explore the effects of SLC protein on intestinal HCO^-₃ excretion and acid-base regulation, <italic>Gymnocypris przewalskii</italic> was exposed to fresh water and saline-alkaline lake water treatments. 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid disodium salt hydrate (DIDS) was injected to control the activity of SLC protein, the intestinal HCO^-₃ excretion concentration, blood physiological indices, and the relative expression of <italic>SLC</italic>4<italic>A</italic>1, <italic>SLC</italic>4<italic>A</italic>2, <italic>SLC</italic>4<italic>A</italic>4, <italic>SLC</italic>26<italic>A</italic>6 genes in the intestine of <italic>Gymnocypris przewalskii</italic> were detected. Results showed that under saline-alkaline environment, the blood pH of <italic>Gymnocypris przewalskii</italic> increased significantly, while the <italic>P</italic>_CO₂ decreased, the concentration of intestinal HCO^-₃ excretion and the expression levels of <italic>SLC</italic>4<italic>A</italic>1, <italic>SLC</italic>4<italic>A</italic>4, and <italic>SLC</italic>26<italic>A</italic>6 genes increased significantly. After the injection of DIDS, the blood pH and HCO^-₃ concentration of <italic>Gymnocypris przewalskii</italic> in the fresh water group increased significantly while <italic>P</italic>_CO₂ decreased; in saline-alkaline water group, the blood pH and HCO^-₃ concentration of <italic>Gymnocypris przewalskii</italic> increased significantly, and the intestinal HCO^-₃ excretion concentration declined. Results indicated that <italic>Gymnocypris przewalskii</italic> intestinal HCO^-₃ excretion in saline-alkaline environment increased, but the excretion declined with the inhibition of SLC family proteins, leading to blood pH increase and acid-base imbalance. This study indicate that the SLC family protein may play a compensatory role in the adaptation of <italic>Gymnocypris przewalskii</italic> to high saline-alkaline environment.

Organic Electron Donor‐Acceptor Co‐intercalated NiMn‐LDHs – Photocatalysts with Enhanced Separation of Charge Carriers for Photocatalytic Reduction of CO2

AbstractDeveloping good photocatalysts for reducing CO2 to carbonaceous fuels has aroused interest. However, the efficiency of photocatalytic CO2 reduction remains low. In this work, we report a novel organic electron donor‐acceptor system to realize the two dimensional photoinduced electron transfer (PET) process by coprecipitation‐in situ oxidation method to synthesize 4,4′‐diaminostilbene‐2,2′‐disulfonic acid (DAS) and 4,4′‐dinitrostilbene‐2,2′‐disulfonic acid disodium salt (DNS) co‐intercalated Ni2Mn‐LDHs (Ni2Mn‐LDHs‐DAS, DNS). Due to the two‐dimensional confinement of LDHs, DAS and DNS were arranged in a single molecule parallel in the interlayer, resulting in a π‐π interaction between the two organic anions. It promoted the photogenerated electrons by the DAS‐DNS to migrate to the hydrotalcite layer to participate in CO2 photoreduction rather than recombination with the holes. The optimum Ni2Mn‐DAS, DNS‐n showed the highest total consumed electron number of 13.99 μmol g−1, which was 3 times higher than that of Ni2Mn−CO3. Our findings provide a new way for improving the CO2 photoreduction activity of hydrotalcite‐based photocatalysts and achieve the combination of organic and inorganic semiconductors.

Preparation and Application of Aromatic Polymer Proton Exchange Membrane with Low-Sulfonation Degree

4,4′-Dichlorodiphenylsulfone-3,3′-disulfonic acid (disodium) salt and 4,4′-difluorodiphenylsulfone were used as sulfonated monomer. 4,4′-Fluorophenyl sulfones were used as the nonsulfonated monomer. 4,4′-Dihydroxy diphenyl ether or 4,4′-thiodibenzenethiol was used as the comonomer. The sulfonated poly (aryl ether sulfone) (SPES) and sulfonated poly (arylene thioether sulfone) (SPTES) with sulfonation degree of 30% and 50% were successfully prepared by nucleophilic polycondensation. Two kinds of aromatic polymer proton exchange membranes were prepared by using sulfonated poly phthalazinone ether ketone (SPPEK) material and fluidization method. The performance of the prepared aromatic polymer proton exchange membrane was researched by the micromorphology, ion exchange capacity, water absorption and swelling rate, oxidation stability, tensile properties, and proton conductivity. Experimental results show that there is no agglomeration in the prepared aromatic polymer proton exchange membrane. The ion exchange capacity is 0.76–1.15 mmol/g. The water absorption and swelling rate increase with the increase of sulfonation degree. The sulfonated poly (aryl ether sulfone) membrane shows better oxidation stability than sulfonated poly (aryl sulfide sulfone). They have good mechanical stability. The prepared aromatic polymer proton exchange membrane with low sulfonation degree has good performance, which can be widely used in portable power equipment, electric vehicles, fixed power stations, and other new energy fields.

DIDS inhibits Vibrio vulnificus cytotoxicity by interfering with TolC-mediated RtxA1 toxin secretion

Vibrio vulnificus (V. vulnificus) infection, frequently resulting in fatal septicemia, has become a growing health concern worldwide. The present study aimed to explore the potential agents that could protect against V. vulnificus cytotoxicity, and to analyze the possible underlying mechanisms. First, we observed that 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid disodium salt hydrate (DIDS) significantly suppressed V. vulnificus cytotoxicity to host cells by using a lactate dehydrogenase (LDH) assay. DIDS did not exhibit any effect on host cell viability, bacterial growth, microbial adhesion and swarming motility. DIDS effectively lowered V. vulnificus RtxA1 toxin-induced calcium influx into host mitochondria and RtxA1 binding to host cells. To further elucidate the underlying mechanism, the synthesis and secretion of RtxA1 toxin were investigated by Western blotting. Intriguingly, DIDS selectively inhibited the secretion of RtxA1 toxin, but did not influence its synthesis. Consequently, the outer membrane portal TolC, a key conduit for RtxA1 export coupled with tripartite efflux pumps, was examined by RT-PCR and Western blotting. We found that DIDS significantly reduced the expression of TolCV1 protein at the transcriptional level. Taken together, these results suggest that DIDS is a promising new paradigm as an antimicrobial drug that targets TolC-mediated toxin.

A chloride channel in rat pancreatic acinar AR42J cells is sensitive to extracellular acidification and dependent on ROS

Extracellular acidification, playing a promoting role in the process of acute pancreatitis, has been reported to activate Cl− channels in several types of cells. However, whether extracellular acidification aggravates acute pancreatitis via activating Cl− channels remains unclear. Here, we investigated the effects of extracellular acidification on Cl− channels in rat pancreatic acinar AR42J cells using whole-cell patch-clamp recordings. We found that extracellular acidification induced a moderately outward-rectified Cl− current, with a selectivity sequence of I− > Br− ≥ Cl− > gluconate−, while intracellular acidification failed to induce the currents. The acid-sensitive currents were inhibited by Cl− channel blockers, 4,4′-Diisothiocyanatostilbene-2,2′-disulfonic acid disodium salt hydrate and 5-Nitro-2-(3-phenylpropylamino) benzoic acid. After ClC-3 was silenced by ClC-3 shRNA, the acid-sensitive Cl− currents were attenuated significantly, indicating that ClC-3 plays a vital role in the induction of acid-sensitive Cl− currents. Extracellular acid elevated the intracellular level of reactive oxygen species (ROS) significantly, prior to inducing Cl− currents. When ROS production was scavenged, the acid-sensitive Cl− currents were abolished. Whereas, the level of acid-induced ROS was unaffected with silence of ClC-3. Our findings above demonstrate that extracellular acidification induces a Cl− current in pancreatic acinar cells via promoting ROS generation, implying an underlying mechanism that extracellular acidification might aggravate acute pancreatitis through Cl− channels.

Synthesis and characterization of star-shaped sulfonated new poly(ether triazole)s: Proton exchange membrane properties

Several star-shaped sulfonated poly(ether triazole)s abbreviated as PTAPSH-XX was prepared by Cu (I) catalyzed click polymerization of a mixture of a new tri-azide monomer namely, 4,4-tris[3-trifluoromethyl-4(4-azidophenoxy)phenyl]biphenyl (PGZ) (B3) and 4,4′-diazido-2,2′-stilbene disulfonic acid disodium salt (DADSDB) with an equimolar amount 4,4′-(propane-2,2-diyl) bis((prop-2-ynyloxy)benzene) (BPEBPA). The degree of sulfonation of the prepared copolymers was varied by changing the molar ratio of DADSDB in the polymer feed. The monomer and copolymers were characterized by FTIR and NMR spectroscopic techniques. The salt form of the branched copolymers was converted into flexible membranes by solution casting technique using dimethyl sulfoxide (DMSO) as solvent and was converted to their acid form by acidification in 1.5 M H2SO4. The introduction of the branching unit largely governs the physicochemical properties and proton conductivity of the membranes. The polymers displayed desirable set of properties required proton exchange membrane applications like high thermal stability (Td10 ~ 259–290 °C), low water uptake and excellent dimensional integrity. The membranes also displayed improved mechanical properties (TS = 51 to 73 MPa, YM = 2.07 to 2.37 GPa), enhanced oxidative stability and high proton conductivity (44 to 102 mS cm−1 at 80 °C). The TEM images of the PTAPSH-XX membranes revealed excellent phase segregated morphology with the formation of ionic clusters within 15 to 90 nm.

Synthesis and characterization of chemically stable sulfonated copoly(triazole imide)s with high proton conductivity

The synthesis and characterization of a series of new sulfonated copoly(triazole imide)s (PTPQSH‐XX) are reported in this work. The PTPQSH‐XX with different degree of sulfonation (DS) were prepared by click polymerization of equimolar amounts of a diimide‐based dialkyne monomer, namely bis‐N,N′‐(prop‐2‐ynyl)pyromellitic diimide (TP) and a mixture of two different diazide monomers (one sulfonated, 4,4‐bis[3′‐trifluoromethyl‐4′{4‐azidobenzoxy} benzyl] biphenyl, and another nonsulfonated, 4,4′‐diazido‐2,2′‐stilbene disulfonic acid disodium salt [SAZ]), in different molar ratios. The copolymers showed high inherent viscosity (1.12–1.28 dL/g) in n‐methyl pyrrolidone (NMP) indicating the formation of high molar masses. Freestanding membranes were prepared from these copolymers by solution casting method. DS of the copolymers was determined from 1H NMR signal intensities, and the values were in good agreement with the quantity of SAZ monomer used in polymer feed, indicating the successful incorporation of the sulfonated monomer. The copolymers exhibited high thermal and mechanical stabilities. The PTPQSH‐80 membrane showed proton conductivity as high as 178 mS/cm at 90°C with good oxidative and hydrolytic stability. Cross‐sectional transmission electron microscope micrographs of the membranes indicated phase segregated morphology along with interconnected hydrophilic domains with dimension in the range 15–150 nm. POLYM. ENG. SCI., 59:2279–2289, 2019. © 2019 Society of Plastics Engineers

Stable polymer/inorganic composite multilayers using covalent cross-linking assisted by a magnetic field

In this study, stable composite multilayers incorporating magnetic montmorillonite (MMT) and weak polyelectrolyte were prepared under the assistance of a magnetic field. We reported a facile method for fabrication of covalently cross-linked Layer-by-Layer (LbL) multilayers using a photosensitive cross-linking agent 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt that carried double azido groups. The multilayers after cross-linking presented improved stability against extreme solution conditions (basic solution pH = 14), and over 78.15% of magnetic MMT remained on the substrate, in clear contrast with the non-cross-linked multilayers, for which less than 8% of the magnetic MMT remained. The results of UV–Vis spectroscopy and scanning electron microscopy (SEM) measurements supported the improvement in the stability of the multilayers. Moreover, the assistance of the external magnetic field improved the LbL assembly efficiency and the cross-linking step achieved the molecular retarded release. When gauze was used as the substrate, the mass loading under the magnetic field was approximately 0.976 mg/cm2, which was 4.2 times the amount deposited on gauze without an external magnetic field. After interfacial modification of gauze using LbL multilayers, the static contact angle transformed from hydrophobic (111.25°) to perfect hydrophilic. When we employed aspirin as the target drug, it took 23 h for the cross-linked multilayers to achieve saturated release, as opposed to 9 h for the non-cross-linked multilayers.

Amphoteric ion-exchange membranes with superior mono-/bi-valent anion separation performance for electrodialysis applications

Fabricating stable mono-/multi-valent anion-selective membranes with high perm-selectivity for electrodialysis (ED) applications is critical but challengeable. In this work, we have fabricated a series of novel homogeneous monovalent anion-selective amphoteric ion-exchange membranes (AIEMs, PAES-im-Xc) based on a long-side-chain type imidazolium-functionalized poly(arylene ether sulfone) cross-linked with 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt (DAS) for ED. By tuning the mass percent of DAS added, low swelling ratio but appreciably high anion perm-selectivity (in Cl–/SO42– system) of optimized AIEM are achieved to values of 8.0% and 47.12 at current density of 2.5 mA cm–2, respectively. In particular, at an enhanced current density of 5.0 mA cm–2, its perm-selectivity reaches 12.5, significantly outperforming commercial monovalent anion-selective Neosepta ACS (5.27). The appreciably high perm-selectivity possibly arises from pore-size sieving effect from dense matrix structure with cross-linkings and strong electrostatic repulsion between negative fixed –SO3– groups and negative divalent ions of SO42– in feeding solution. The superior performances might be particularly interesting findings that can facilitate the development of advanced mono-/bi-valent anion-selective membranes in applications of sea water desalination, resource recovery and water treatment/pretreatment etc..

Synthesis, Characterization, and Antimicrobial Activity of Novel Sulfonated Copper-Triazine Complexes.

Metallotriazine complexes possess interesting biological and medicinal properties, and the present study focuses on the synthesis, characterization, and antimicrobial activity of four novel copper-triazine derivatives in search of potent antibacterial and antifungal drug leads. In this study, 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4,4′-disulfonic acid monosodium salt (L1, ferrozine) and 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5,5′-disulfonic acid disodium salt (L2, ferene) have been used as ligands to study the complexation towards copper(II). The synthesized complexes, [CuCl2(ferrozine)]·7H2O·MeOH (1), [CuCl2(ferrozine)2]·5H2O·MeOH (2), [CuCl2(ferene)]·H2O·MeOH (3), and [CuCl2(ferene)2]·H2O·MeOH (4), have been characterized spectroscopically, and preliminary bioassays have been carried out. FTIR spectroscopic data have shown that N=N and C=N stretching frequencies of complexes have been shifted towards lower frequencies in comparison with that of the ligands, confirming new bond formation between Cu and N, which in turn lowers the strength of N=N and C=N bonds. In addition, a bathochromic shift has been observed for UV-visible spectra of complexes (1), (2), (3), and (4). Furthermore, elemental analysis data have been useful to obtain empirical formulas of these complexes and to establish the purity of each complex. Complexes (1) and (2) have shown antibacterial activity for both S. aureus (ATCC® 25923) and E. coli (ATCC® 25922) at 1 mg/disc concentration, and ferrozine has shown a larger inhibition zone against the clinical sample of C. albicans at 1 mg/disc concentration in comparison with the positive control, fluconazole.

Synthesis and Characterization of Highly Proton Conducting Sulfonated Polytriazoles

This article describes the synthesis and characterization of highly sulfonated polytriazole copolymers (PTSQSH-I to IV) with IECw values ranging from 2.41 to 3.49 mequiv g–1. The copolymers were synthesized by click reaction between equimolar amount of a dialkyne monomer, potassium 2,5-bis(2-propyn-1-yloxy)benzenesulfonate, and a mixture of two different diazide monomers, 4,4-bis[3′-trifluoromethyl-4′(4-azidobenzoxy)benzyl]biphenyl and 4,4′-diazido-2,2′-stilbene disulfonic acid disodium salt. The copolymers were characterized by Fourier transform infrared and NMR spectroscopy techniques. The membranes were prepared by dissolving the salt form of the copolymers in dimethyl sulfoxide. The copolymers showed high thermal, mechanical, and oxidative stabilities, and the acidified membranes showed very high proton conductivity (43–173 and 132–304 mS cm–1 at 30 and 80 °C, respectively). Transmission electron microscopy images confirmed the formation of well-phase-separated morphology with interconnected hydrophilic domains (20–150 nm).

Facile preparation of novel layer-by-layer surface ion-imprinted composite membrane for separation of Cu2+ from aqueous solution

A novel surface ion-imprinted composite membrane was fabricated using layer-by-layer technology for selective adsorption separation of copper ion. The ion-imprinted multilayer was introduced on modified polyethersulfone substrates by electrostatic interaction. Photocrosslinking was initiated by adding 4,4′-diazostilbene-2,2′-disulfonic acid disodium salt and template ions were eluted by HAc solution. Effects of preparation and adsorption conditions, such as cationic polyelectrolyte species, crosslinking agent concentration, assembly layer number, pH and initial Cu(II) concentration, on adsorption behaviors were investigated. Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscope and X-ray photoelectric spectroscopy were used for the characterization of the copper ion-imprinted membrane (Cu-IIM). Batch adsorption experiments for studies of adsorption kinetics, adsorption selectivity and stability were conducted. The maximum adsorption capacity reached up to 48.0 mg·g−1 when 3.5 bilayers were deposited on the surface of membrane under specific experimental conditions (C0 = 200 mg·L−1, pH 6.0, 400 mL, 25 °C). The Cu-IIM exhibited a higher selectivity for copper ions when competitive ions were present. In addition, the Cu-IIM showed good stability. Moreover, according to the observation of the surface color change of the Cu-IIM during the adsorption process, the membrane could be used for qualitative concentration detection of copper ions in aqueous solution.

Synthesis, Characterization, and BSA-Binding Studies of Novel Sulfonated Zinc-Triazine Complexes.

Four Zn(II) complexes containing a pyridyl triazine core (L1 = 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5′,5″-disulfonic acid disodium salt and L2 = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4′,4″-disulfonic acid sodium salt) were synthesized, and their chemical formulas were finalized as [Zn(L1)Cl2]·5H2O·ZnCl2 (1), [Zn(L1)2Cl2]·4H2O·2CH3OH (2), [Zn(L2)Cl2]·3H2O·CH3OH (3), and [Zn(L2)2Cl2] (4). The synthesized complexes are water soluble, making them good candidates for biological applications. All four complexes have been characterized by elemental analysis and 1H NMR, IR, and UV-Vis spectroscopy. The IR stretching frequency of N=N and C=N bonds of complexes 1–4 have shifted to lower frequencies in comparison with free ligands, and a bathochromic shift was observed in UV-Vis spectra of all four complexes. The binding studies of ligands and complexes 1–4 with bovine serum albumin (BSA) resulted binding constants (K b) of 3.09 × 104 M−1, 12.30 × 104 M−1, and 16.84 × 104 M−1 for ferene, complex 1, and complex 2, respectively, indicating potent serum distribution via albumins.

Proton Exchange Membrane Based on Sulfonated Poly (Aromatic Imide-Co-Aliphatic Imide) for Direct Methanol Fuel Cell

A new sulfonated poly(aromatic imide-co-aliphatic imide) (SPI) for the use as a polymer electrolyte membrane was successfully synthesized from 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenylmethane-2,2'-disulfonic acid disodium salt (S-DDM), hexamethylenediamine, and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in a one-step reaction. S-DDM was prepared by the direct sulfonation of DDM monomer. The degree of sulfonation of the sulfonated copolyimide was varied by using various molar concentrations of S-DDM. The sulfonated copolyimide with the highest degree of sulfonation possessed the proton conductivity of 0.0032 S.cm-1 in a wet state. The highest methanol permeability of the sulfonated copolyimide was 2.75 × 10-8 cm2.s-1 which is ~425 times lower than that of the Nafion 117. The highest membrane selectivity belonged to the membrane with 34% degree of sulfonation with the value of 1.65 × 106 s.S.cm-3 which is three orders of magnitude higher than the commercial Nafion 117.

Hydroquinone Based Sulfonated Copolytriazoles with Enhanced Proton Conductivity

AbstractA series of new fluorinated sulfonated copolytriazoles (PTHQSH‐XX) with ion exchange capacity (IECw) values ranging from 1.66 to 2.82 meq g−1 are prepared via cuprous ion catalyzed azide‐alkyne click polymerization reaction between 1,4‐bis(prop‐2‐ynyloxy)benzene, 4,4′‐diazido‐2,2′‐stilbene disulfonic acid disodium salt (SA), and 4,4‐bis[3′‐trifluoromethyl‐4′(4‐azidobenzoxy) benzyl] biphenyl (QAZ). The degree of sulfonation of the copolytriazoles is adjusted between 60% and 90% by varying the molar ratio of sulfonated monomer (SA) to the nonsulfonated monomer (QAZ). The structure of the copolytriazoles is characterized by Fourier transform infrared and NMR spectroscopy. The solution‐cast membranes of these copolymers exhibit high thermal, mechanical, oxidative and hydrolytic stability, and high proton conductivity (19–142 mS cm−1 at 80 °C and 22–157 mS cm−1 at 90 °C). Transmission electron microscopy confirms the formation of good phase separated morphology with ionic clusters in the range of 15–145 nm.

Ultrafast dynamics of two copper bis-phenanthroline complexes measured by x-ray transient absorption spectroscopy

Ultrafast structural dynamics of the metal to ligand charge transfer (MLCT) states of two copper bis-phenanthroline complexes were captured by using x-ray transient absorption (XTA) spectroscopy at the Linac Coherent Light Source and further described by theoretical calculations. These complexes have the general formula [Cu(I)(R)2]+, where R = 2,9-dimethyl-1,10-phenanthroline (dmp) and 2,9-diphenyl-1,10-phenanthroline disulfonic acid disodium salt (dpps). [Cu(I)(dmp)2]+ has methyl groups at the 2,9 positions of phenanthroline (phen) and adopts a pseudo-tetrahedral geometry. In contrast, [Cu(I)(dpps)2]+ possesses two bulky phenyl-sulfonate groups attached to each phen ligand that force the molecule to adopt a flattened tetrahedral geometry in the ground state. Previously, optical transient absorption (OTA) and synchrotron based XTA experiments with 100 ps time resolution have been employed to study the relationship between structural distortions and excited state relaxation pathways in the two complexes. However, the dynamics of the MLCT transition during the first few picoseconds after excitation in these complexes remained unclear because of limitations in element specificity in OTA and in the time resolution of synchrotron sources in XTA. In this experiment, the local coordination geometry and oxidation state of copper were probed with a temporal resolution of ∼300 fs. Unexpectedly, the depletion of the Cu(I) signal due to the MLCT transition was found to be non-impulsive in the case of [Cu(I)(dpps)2]+ with a time constant of 0.6 ps, while the Cu(I) depletion in [Cu(I)(dmp)2]+ was instantaneous within the 300 fs instrument response time. The slower Cu(I) depletion kinetics in [Cu(I)(dpps)2]+, previously unobserved in femtosecond OTA experiments, is likely due to intramolecular motions on the sub-picosecond time scale that could alter the localization of the transferred electron in the phen ligands.