Dimethylformamide Solution Research Articles

Polymer-Free Electrospinning of β-Cyclodextrin-Oligolactide for Magnolol and Honokiol Pharmaceutical Formulations.

Background: Magnolol (MG) and honokiol (HK) are bioactive compounds extracted from Magnolia obovata and Magnolia Officinalis trees with significant pharmacological properties, including antioxidant and antibacterial activity. However, their poor water solubility and low bioavailability limit the therapeutic potential. Methods: To address these limitations, this study aims to develop MG and HK formulations by co-electrospinning using custom-synthesized β-cyclodextrin-oligolactide (β-CDLA) derivatives. MALDI MS and NMR were employed for the structural assessment of the β-CDLA derivatives. This polymer-free electrospinning technique utilizes the high solubility of β-CDLA to incorporate MG and HK into fibrous webs. The morphology of the resulting fibers is established by SEM and further characterized using FTIR and NMR spectroscopy to confirm the successful incorporation of MG and HK. The antioxidant activity was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the antimicrobial activity was evaluated against several standard microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans). Results: The MG and HK electrospun formulations were prepared using highly concentrated feed solutions in dimethylformamide (180% w/v). The resulting β-CDLA fibers, with diameters above 400 nm and an active compound content of 7% wt., exhibited enhanced long-term antioxidant activity and improved antimicrobial efficacy, including notable activity against Escherichia coli. Conclusions: This study demonstrates the potential of MG and HK-loaded β-CDLA fibrous formulations as delivery systems with prolonged antioxidant activity and notable antibacterial efficacy, providing a promising platform for biomedical applications.

Interfacially Cross-Linked Polydopamine/Polybenzimidazole Composite Membranes for Organic Solvent Nanofiltration.

Interfacial cross-linking was used to prepare composite organic solvent nanofiltration (OSN) membranes comprising a polydopamine (PDA) active layer formed on a polybenzimidazole (PBI) substrate. Dibromo-p-xylene (DBX) was employed as a cross-linking agent to make the composite membranes chemically stable against harsh polar aprotic solvents. The interfacial cross-linking of PDA/PBI allowed for finely tuning the molecular weight cutoff (MWCO) of the membrane, resulting in a membrane with precise molecular separation capabilities for OSN. The morphology and surface properties of the membranes were characterized, and a membrane with a MWCO of 286 Da was investigated for OSN of a series of solvents. The membrane permeance was in the order of acetonitrile (MeCN) > methanol (MeOH) > acetone > toluene > dimethylformamide (DMF) > heptane > ethanol (EtOH) > isopropanol (IPA) > tetrahydrofuran (THF). The membranes displayed a sharp pore size distribution, yielding a rejection rate of over 99% for Rose Bengal (RB, MW 1020 g/mol) and Remazol brilliant blue (RBB, MW 626.5 g/mol) from DMF and EtOH solutions. When it came to methyl orange (MO, MW 327.3 g/mol) that had a molecular weight closer to the MWCO of the membrane, the membrane still displayed a high rejection rate of 95% and 99% in nanofiltrating solvents DMF and EtOH, respectively. In addition, it was demonstrated that the membrane was able to effectively fractionate mixed solutes having molecular weights appropriate for the MWCO rating of the membrane during OSN.

Hydrogen bond, protonation, and coordination-induced supramolecular chirality inversion in glutamide-based amphiphilic self-assembly

In this study, we have synthesized two types of Y-shaped chiral amphiphiles, namely L-BG and L-PG, with a benzene or pyridine ring at the terminal position, respectively. The optimized conformations of both amphiphiles indicate the presence of intramolecular interactions. In dimethylformamide (DMF) solution at the monomeric state, both amphiphiles exhibit positive cotton effects; however, in DMF/H2O mixed solution, the cotton effects are inverted. Molecular dynamics simulations reveal that both intermolecular and intramolecular hydrogen bonds facilitate the inversion of supramolecular chirality. Additionally, protonation and coordination of L-PG assembly results in chirality inversion and transformation of emission. This study emphasizes the significance of both inter- and intramolecular hydrogen bonds in the assembly process, providing insights into stimuli-responsive chiral supramolecular materials.

Synthesis, structural characterization and third-order nonlinear optical study of W/Cu/S cluster-based coordination polymers with thioether-containing ligands

The assembly of [Et4N][Tp*WS3] (Et = ethyl, Tp* = tetrakis(3,5-dimethyl-1-pyrazolyl)borate), Cu(I) with 1,3,5-tri((pyridin-4-ylthio)methyl)benzene (tptmb) or 4,4′-bis((pyridin-4-ylthio)methyl)-1,1′-biphenyl (bptmb) leads to two coordination polymer with the formulae of {[Tp*WS3Cu3(tptmb)(CH3CN)](PF6)2·CHCl3·2CH3CN}n (1·CHCl3·2CH3CN) and {[(Tp*WS3Cu3)2(bptmb)3(CH3CN)](PF6)4·5CH2Cl2·1.5CH3CN}n (2·5CH2Cl2·1.5CH3CN), respectively. Compounds 1 and 2 were characterized by elemental analysis, infrared spectroscopy, UV–vis spectroscopy, high-resolution electrospray ionization mass spectrometry, and single-crystal X-ray diffraction. In 1, each tptmb ligand connects two adjacent cluster nodes by its three coordination arms, forming a cluster-based one-dimensional zigzag chain. In 2, equal amounts of [Tp*WS3Cu3(CH3CN)]2+ and [Tp*WS3Cu3]2+ clusters serve as three-connected nodes and are alternatively bridged by the bptmb ligands, forming a 2D network. Z-scan tests of 1 and 2 in dimethylformamide (DMF) solution reveal they have reverse saturable absorption with effective nonlinear absorption coefficients of 1.50 × 10−11 m/W for 1 and 5.00 × 10−11 m/W for 2. This work could inspire the construction of coordination polymer structures using cluster nodes and flexible thioether-containing ligands, providing a new way for the development of third-order nonlinear optical materials.

Benzothiazole-quinoline based probe for simultaneous colorimetric detection of CN- and Cu2+ ions, with fluorescence sensing for Cu2+: Mechanistic insights and practical applications in environmental monitoring and cellular analysis

The development and synthesis of notably targeted and colorimetric sensor based on an azomethine compound for the distinct recognition of Cu2+ and CN− ion individually in an aqueous dimethyl formamide solution is performed. In the presence of CN− and Cu2+, the sensor BTZ showed impressive colorimetric changes, going from pale yellow to orange and pale yellow to dark yellow, respectively. In the meantime, FL spectrum (Cu2+) and UV–vis spectroscopy (CN−/Cu2+) were used to assess the sensing features. The plausible binding mechanisms of CN− and Cu2+ ions with sensor BTZ have been studied using the 1H NMR titration, Job's plot and DFT technique. The bathochromic shift produced by the intramolecular charge transfer (ICT) transition may have been the source of the phenomenon. Furthermore, CN− ion in the commercial substance is quickly identified and measured with the naked eye by using sensor BTZ. It was found that the BTZ's LOD for CN− and Cu2+ was 0.280 × 10−7 M and 1.153 × 10−7 M, respectively. Moreover, 1:1 binding ratio for the reaction of CN− and Cu2+ ions with sensor BTZ were demonstrated by Job's plot, which was dependent on analytical data. The findings show that BTZ is an easy-to-use and practical probe for concurrently sensing cyanide and copper ions in environmental samples and living cells that have less cytotoxicity.

Triphenylamine-Based Solid-State Emissive Fluorene Derivative with Aggregation-Induced Emission Enhancement Characteristics

Aggregation-induced emission (AIE) has garnered considerable attention in recent years. Understanding the mechanisms underlying AIE phenomena is crucial. Here, we present the design and synthesis of a novel fluorene derivative (4) based on triphenylamine, which exhibits typical AIE properties. The structure of it was totally characterized using FT-IR, MALDI-TOF mass analysis, elemental analysis, 1H, and 13C NMR spectroscopy. It displayed strong solid-state emission with diverse fluorescence characteristics. The AIE property of the compound was systematically studied using photoluminescence spectroscopy, revealing a distinct yellow light-emitting phenomenon. The solid-state luminescence showed a red shift of 148 nm compared to its luminescence in dilute dimethylformamide (DMF) solutions. Moreover, photophysical characteristics, including absorption and emission spectra, as well as fluorescence lifetime, were examined using UV–vis absorption and fluorescence emission spectroscopy. Compound (4) exhibited superior photosensitization abilities in both solid and solution states, with a notably enhanced effect observed in the solid state compared to the solution state.

Antiviral effect of oversulfated kappa-carrageenan derivatives against COVID-19 for spray coating application on facemasks

The COVID-19 pandemic caused by SARS-CoV-2 has spurred the urgent need for effective antiviral strategies. In this work, we explored the potential of oversulfated kappa-carrageenan (OSKC) in spray-coated facemasks for SARS-CoV-2 inhibition pathway. The sulfated derivative was synthesized with sulfur trioxide pyridine complex in dimethylformamide solution. The antiviral efficacy of OSKC at different concentrations and spray-coated facemasks was evaluated using betacoronavirus Murine Hepatitis Virus strain 3, revealing a significant reduction in viral load compared to commercial kappa-carrageenan. Furthermore, the characterization techniques assessed the effect of the position of the introduced sulfate groups on the antiviral activity and on the physicochemical characteristics. OSKC is able to bind specific proteins of enveloped viruses, preventing viral attachment into target cells. Overall, this study demonstrates the feasibility and effectiveness of OSKC spray coating for breathable facemasks with antimicrobial properties, offering a promising approach to enhancing personal protective equipment against viral transmission in healthcare and community settings.

The functional moieties impact on optical, thermal, and nonlinear properties of chalcone derivatives. A comprehensive study on FT2MP

This study explains the intricate interplay between functional groups and the single crystal structure of the compound 1-(furan-2-yl)-3-(2,4,6-trimethoxyphenyl)prop-2-en-1-one (FT2MP) using Density Functional Theory (DFT) calculations. Notably, geometry optimization at B3LYP using 6-311G+(2d,p) closely aligned with experimental distances from X-ray diffraction (XRD) upon comparison. A Q-switched, frequency-doubled pulsed Nd. YAG laser (532 nm, 7 ns pulses), a 25 cm focal length lens, and a 0.001 mol/L FT2MP solution in Dimethylformamide was used to measure third-order nonlinear optical (NLO) parameters and subsequently the origin of second/third harmonic generation efficiency is discussed. The third-order nonlinear parameters of FT2MP were found to be Δɸ = 0.95, n2 = −9.605 × 10−9 cm2/W, β = 2.74 × 10−6 cm/W, and χ(3) = 5.58 × 10−7 esu. Information about the electronic structure and reactivity of the molecule is provided via the addition of Global Chemical Reactivity Descriptors (GCRD), molecular electrostatic potential (MEP) and Frontier Molecular Orbitals (FMOs) for electronic structure and reactivity insights. Hirshfeld surface analysis was used to study intermolecular interactions. This investigation indicates the potential of FT2MP for third harmonic generation, providing a comprehensive understanding of its molecular structure, reactivity, and intermolecular interactions.

A clean bamboo-based carbon-iron multi-interface complex for electromagnetic radiation attenuation and thermal insulation

Civilian electromagnetic wave (EMW) absorbers are urgently needed to solve the excessive electromagnetic (EM) radiation energy pollution. Biomass, such as wood and bamboo, has a wide range of sources, is porous, and is suitable for forming functional composites. However, the diverse composition and microstructure directly affect the EM and thermal properties of conversion composites, and the corresponding influencing mechanisms are unclear. Here, a series of iron-containing biochar-based composites (CFBs) were synthesized by in-situ pyrolysis of impregnated flattened bamboo sliced veneers with Fe(acac)3 dimethylformamide (DMF) solutions. The components and microstructures were pre-regulated through moisture-heat coupling softening, flattening and slicing treatments. Excellent EMW absorption performance with a |RLmin| value as large as 33.03 dB was obtained for CFB-0.8 at a fixed thickness of 1.15 mm, along with the widest effective frequency bandwidth as large as 4.08 GHz. Besides, In addition, CFB-0.8 has stable Joule heating performance (0.9V, 79.7 °C), and its in-plane thermal conductivity is 31.4 times that of flattened bamboo (0.62 W m−1 K−1). These are attributed to the rich heterojunction interfaces, electromagnetic attenuation caused by structures (porous structure scattering, nanoscale effects), deep absorption mechanisms caused by defects (lattice defects, electric field concentration, non-uniform carbonization structures), and thermal conversion. This work provides theoretical and experimental data for developing EMW absorption materials and new ideas for the high-value utilization of biomass materials and the continuation of their carbon fixation life.

Theoretical Investigation of the Pyridinium-Inspired Catalytic Dehydration of Heptafluoro-Iso-Butyramide for the Synthesis of Environmentally Friendly Insulating Gas Heptafluoro-Iso-Butyronitrile.

Heptafluoro-iso-butyronitrile (i-C3F7CN) represents a feasible eco-friendly replacement gas for the most potent greenhouse gas sulfur hexafluoride in various high-voltage power transmission equipment. The reaction mechanisms for the in situ synthesis of i-C3F7CN from heptafluoro-iso-butyramide [i-C3F7C(O)NH2] in the presence of trifluoroacetic anhydride (TFAA) and pyridine (Py) in dimethylformamide solution have been studied within density functional theory with M06-2X exchange-correlation functional with the 6-311++G(d,p) basis set and the high-level ab initio complete basis set quadratic CBS-QB3 method. It is revealed that the unimolecular dehydration of i-C3F7C(O)NH2 can be catalyzed efficiently by TFAA in terms of both kinetic and thermodynamic aspects, producing i-C3F7CN and trifluoroacetic acid (TFA). Furthermore, Py is capable of reducing the energy barrier of the rate-determining step through hydrogen abstraction to form pyridinium hydrogen. The synergic effect of the TFAA/Py co-catalyst plays a pivotal role in the production of i-C3F7CN as the Gibbs free energy barrier can be lowered by more than 40 kcal/mol with the ratio of TFAA:2Py, in accordance with the experimental observation. The present theoretical work provides new insights into the rational design on the novel catalysts for large-scale synthesis of the perfluorinated nitriles.

Room‐Temperature Afterglow Nanostructures via Block Copolymer Self‐Assembly

AbstractMiniaturization of organic afterglow materials has shown promising application in biomedical and other areas. Current technologies, such as nanoprecipitation, mechanical treatment, and emulsion polymerization, lack the capability of facile control on the morphology and dimension of the miniaturized organic afterglow materials. Here we report the fabrication of organic afterglow nanostructures via block copolymer self‐assembly at room temperature. The fabrication is based on two‐component design strategy where hydrophobic luminescent emitters with small rate constants of phosphorescence decay or reverse intersystem crossing are designed as the first component. Amphiphilic block copolymers that can form spherical core‐shell micelles and worm‐like micelles with glassy hydrophobic cores are used as the second component. Upon addition of water into a dimethylformamide solution that contains the two components, the amphiphilic block copolymers self‐assemble into well‐defined nanostructures and accommodate the hydrophobic luminescent emitters in nanostructure's hydrophobic cores. After switching to pure water by dialysis, room‐temperature afterglow nanostructures have been obtained because of the excellent protection of organic triplets by the glassy hydrophobic cores. The afterglow nanostructures exhibit intriguing afterglow mechanism modulated by the types of luminescent emitters, controlled dimensions and morphologies by the structural parameters of the block copolymers.

Synthesis and Characterization of Ni based Metal Organic Framework for Enhancing the Removal of Typical Organic Dyes

In this report we present a simple synthesis of a nickel-based metal organic framework (MOF-Ni) at the room temperature using a solution of dimethylformamide (DMF), ethanol and distilled water. The MOF-Ni synthesized in various solvents displayed numerous different properties and advantages over other materials including easy synthesis procedure, good crystallinity, rigidity, and robust chemical stability. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetric analysis (TGA) were employed to analyze the as-synthesized MOF-Ni. The as-obtained MOF-Ni was used to investigate its adsorption kinetics of red telon dye (RTL) molecules. The effects of time (30–270 min), initial RTL concentration (20–300 mg/L), adsorbent dose (2–50 mg), solution pH (2–12), and temperature (10–80 °C) were investigated. The pseudo-first order rate equation was able to provide the best description of the adsorption kinetics data in the studied time scale. The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms, and the isotherm constants were also determined. Dye adsorption turned out to strongly depend on pH, and a low pH was found to increase the amount of adsorbed dyestuff. Compared with other samples, MOF-Ni synthesized in (DMF ​+ ​C2H5OH ​+ ​H2O) had a significantly enhanced adsorption ability for RTL dye. The MOF-Ni high adsorption capacity for RTL dye was attributed to the electrostatic attraction/repulsion phenomena. Moreover, MOF-Ni showed an improved stability at 370, 417, and 423 °C temperatures. The results obtained through our experiments suggested that our porous MOF-Ni microstructures synthesized in DMF ​+ ​C2H5OH ​+ ​H2O have potential applications for treating wastewaters containing RTL dyes.

Chiral Hydroxy Metabolite of Mebendazole: Analytical and Semi-Preparative High-Performance Liquid Chromatography Resolution and Chiroptical Properties.

Mebendazole (MBZ) is a benzimidazole carbamate anthelmintic used worldwide for the treatment and prevention of parasitic disorders in animals and humans. A large number of in vivo and in vitro studies have demonstrated that MBZ also has anticancer activity in multiple types of cancers. After oral administration, the phenylketone moiety of MBZ is rapidly reduced to the hydroxyl group to form the chiral hydroxy metabolite (MBZ-OH). To the best of our knowledge, there is no information in the literature on the stereochemical course of transformation and the anthelmintic and antitumor activity of individual enantiomers of MBZ-OH. In the present study, we describe in detail the direct HPLC resolution of MBZ-OH on a 100 mm × 4.6 mm Chirapak IG-3 column packed with 3 μm silica particles containing amylose (3-chloro-5-methylphenylcarbamate) as a selector. At 25 °C and using pure methanol as the mobile phase, the enantioseparation and resolution factors were 2.38 and 6.13, respectively. These conditions were scaled up at a semi-preparative scale using a 250 mm × 10 mm Chiralpak IG column to isolate multi-milligram amounts of both enantiomeric forms of the chiral metabolite. The chiroptical properties of the collected enantiomers were determined and, through a theoretical study, were related to the more stable conformations of MBZ-OH. The first and second eluted enantiomers were dextrorotatory and levorotatory, respectively, in dimethylformamide solution. Finally, by recording the retention factors of the enantiomers as the water content in the water-acetonitrile mobile phases was progressively varied, U-shaped retention maps were generated, indicating a dual and competitive hydrophilic interaction liquid chromatography and reversed-phase liquid chromatography retention mechanism on the Chirapak IG-3 chiral stationary phase.

Synthesis of an ultrathin, self-adhesive, tough, and frigostable BP@PVP/TPU ionogel for strain sensors by electrospinning

Intelligent wearable strain sensors are indispensable for monitoring human locomotion and human–machine interactions. Herein, we present a nanocomposite ionogel film (thickness of 0.2 mm) prepared using polyvinylpyrrolidone (PVP), polyurethane (TPU), 1-butyl-3-methylimidazolium hexafluorophosphate, and black phosphorus (BP) in a dimethylformamide solution, referred to as BP@PVP/TPU, using the electrostatic spinning. While the ionogel film exhibited exceptional properties, including excellent self-adhesiveness, high tensile strength (1866 %), and high fracture strength (0.59 MPa), at room temperature, it displayed high tensile strength (940 %) and high fracture strength (3.01 MPa) even when stored at −35 °C for up to 15 days. Subsequently, a self-adhesive strain sensor was fabricated from the BP@PVP/TPU ionogel using copper wire. After 1000 pull-up cycles under 30 % strain, the sensing signal remained essentially unchanged, and the sensor exhibited satisfactory adhesion to different substrates (e.g., an impressive adhesion strength of up to 299 kPa to iron sheets). The excellent performance of the BP@PVP/TPU ionogel enabled the developed sensor to monitor various human body movements in real time. This approach is both economical and convenient and provides an innovative avenue for developing next-generation wearable strain sensors.

Polyamide thin-film composite membranes with enhanced interfacial stability for durable organic solvent nanofiltration

Polyamide thin-film composite (TFC) membranes present a promising option for organic solvent nanofiltration (OSN) due to their superior advantages in facile fabrication and high separation efficiency. However, existing TFC-based OSN membranes are heavily limited by their weak interfacial stability in organic solvents, because many solvent-resistant porous supports are hydrophobic and have poor interfacial compatibility to polyamide. Herein, we report a polyamide TFC membrane with enhanced interfacial stability and durable OSN performance, by multifunctional surface modification and in-situ interfacial polymerization on a hydrophobic and solvent-resistant polypropylene substrate. Distinct from nascent ones, the polypropylene substrates modified by tannic acid/aminopropyltriethoxysilane coating possess excellent hydrophilicity and more functional groups, in which the former allows for the in-situ synthesis of integral polyamide layers via interfacial polymerization and the latter greatly enhances the binding strength between the polyamide layer and PP substrate by 30 times. With this method, the TFC membranes exhibit excellent thermal stability in 80 °C dimethylformamide solution. Meanwhile, the TFC membranes display high ethanol permeance (9.2 L m−2 h−1 bar−1) and acid fuchsin rejection (98.5 %), outperforming the performance of most OSN membranes reported. This straightforward method, robust structural stability, and extraordinary performance make the TFC membranes a step closer to commercial OSN membranes.

Experimental investigation of PCL‐based composite material fabricated using solvent‐cast 3D printing process

AbstractBone tissue engineering relies on scaffolds with enhanced mechanical properties, achievable through 3D printing techniques. Our study focuses on enhancing mechanical properties using a solvent‐cast 3D printing method. For this, poly‐ε‐caprolactone (PCL) reinforced with polyhydroxybutyrate (PHB), and synthetic fluorapatite (FHAp) nanopowders were utilized, immersed in a solution of dichloromethane (DCM) and dimethylformamide (DMF). Sol–gel method was used to synthesized FHAp, and the XRD pattern confirmed crystalline FHAp presence, with notable peaks at 2θ values of 31.937°, 33.128°, 32.268°, and 25.864°. Moreover, composites exhibited nonchemical PCL‐PHB/FHAp interactions, with PHB and FHAp crystallographic planes evident. Surface roughness, assessed via RMS values, showed progressive increases with higher PHB and FHAp content. Tensile strength peaked at 19% wt/v of PHB, with varied effects of FHAp. Compressive strength reached its apex at 30% wt/v of FHAp, with higher PHB content consistently enhancing strength. Flexural strength notably increased with PHB, peaking at 19% wt/v, and further with FHAp. Young's modulus rose with both PHB and FHAp content. Hardness increased with PHB and FHAp, notably peaking at 30% wt/v of FHAp. Cell viability improved with PHB, showing varied responses to FHAp. Hemocompatibility evaluations indicated low hemolysis percentages, especially in balanced PHB/FHAp compositions. These findings highlight the crucial role of composite compositions in tailoring mechanical and biological properties for optimal bone scaffold design, promising advancements in tissue regeneration technologies.

PAN-based fiber-reinforced carbon-carbon composites for improved fire retardancy and thermal and electrical conductivities for harsh environments

Carbon-carbon (C-C) fiber composites are a new class of materials that are used in various industries due to their exceptional chemical, thermal and electrical conductivities properties. In this study, carbon-carbon fiber composites were manufactured where polyacrylonitrile (PAN) powder was dissolved in dimethylformamide (DMF) solution, and carbon fibers with desired concentrations (20–80 wt%) were immersed into this solution as reinforcement through evaporation and solidification. The PAN-fiber systems were then stabilized at 250–270°C for 120 min in the air and subsequently carbonized at 650, 750, and 850°C for 60 min in the presence of argon gas to obtain the desired C-C fiber composites. Thermogravimetric analysis (TGA) results showed that the carbonized samples had a small weight loss of 2.5%, while actual and oxidized samples had more weight loss. Moreover, the carbonized sample surface was more hydrophobic compared to other samples due to the carbon presence and surface texture changes. Fourier-Transform Infrared (FTIR) spectroscopy peaks showed the presence of different functional groups of PAN before oxidation and carbonization, but those peaks disappeared after oxidation and carbonization. The developed carbon-carbon composite passed the UL94 vertical flame retardancy testing with a V-0 rating. Surface smoothness, proper matrix and reinforcements bonding were confirmed by scanning electron microscopy (SEM) results and the manufactured composite properties changes were validated by the confocal microscopy images. The carbon-carbon fiber composite achieved an electrical conductivity value up to 4.75 × 103 S/m after the carbonization process. The excellent thermal, chemical, and electrical properties of these composites can be useful for numerous industrial applications in different extreme environments.

Synthesis of peripheral thiol functionalized (NiII) phthalocyanine and its attachment on Au electrode for electrochemical determination of L-DOPA

This paper presents the synthesis, characterization, and electrocatalytic behavior of peripheral thiol-functionalized nickel(II) phthalocyanine (4β-NiIITTPc). The complex was synthesized and characterized using MALDI-TOF mass spectra, UV–visible, and FT-IR spectroscopies. Upon self-assembly on the Au surface from dimethylformamide solution, 4β-NiIITTPc forms via the formation of an Au-S bond. The attachment onto the Au surface was verified through Raman spectroscopy and cyclic voltammetry, with characteristic bands at 2572 and 250 cm−1 corresponding to -SH and Au-S stretching vibrations, respectively. Notably, the -SH stretching indicates that not all four -SH groups of 4β-NiIITTPc are involved in chemisorption. The resulting self-assembled film on the Au electrode exhibits well-defined oxidation peaks at +0.34 V and +0.56 V, corresponding to NiIII/NiII and NiIIPc−1/NiIIPc−2, respectively. The surface coverage was estimated from the charge associated with NiII/NiIII oxidation, yielding 1.01 × 10−10 mol cm−2. Finally, the electrocatalytic activity of the self-assembled monolayer (SAM) of 4β-NiIITTPc on Au electrodes was assessed by studying the oxidation of 3,4-dihydroxy-1-phenylalanine (L-dopa) as a probe. The SAM-modified electrode not only shifts the oxidation potential of L-dopa to a less positive potential but also enhances the oxidation current and mitigates electrode surface fouling compared to the bare Au electrode.

Performance of 4,5-diphenyl-1H-imidazole derived highly selective 'Turn-Off' fluorescent chemosensor for iron(III) ions detection and biological applications.

Two fluorescent chemosensors, denoted as chemosensor 1 and chemosensor 2, were synthesized and subjected to comprehensive characterization using various techniques. The characterization techniques employed were Fourier-transform infrared (FTIR), proton (1 H)- and carbon-13 (13 C)-nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization (ESI) mass spectrometry, and single crystal X-ray diffraction analysis. Chemosensor 1 is composed of a 1H-imidazole core with specific substituents, including a 4-(2-(4,5-c-2-yl)naphthalene-3-yloxy)butoxy)naphthalene-1-yl moiety. However, chemosensor 2 features a 1H-imidazole core with distinct substituents, such as 4-methyl-2-(4,5-diphenyl-1H-imidazole-2-yl)phenoxy)butoxy)-5-methylphenyl. Chemosensor 1 crystallizes in the monoclinic space group C2/c. Both chemosensors 1 and 2 exhibit a discernible fluorescence quenching response selectively toward iron(III) ion (Fe3+ ) at 435 and 390 nm, respectively, in dimethylformamide (DMF) solutions, distinguishing them from other tested cations. This fluorescence quenching is attributed to the established mechanism of chelation quenched fluorescence (CHQF). The binding constants for the formation of the 1 + Fe3+ and 2 + Fe3+ complexes were determined using the modified Benesi-Hildebrand equation, yielding values of approximately 2.2 × 103 and 1.3 × 104 M-1 , respectively. The calculated average fluorescence lifetimes for 1 and 1 + Fe3+ were 2.51 and 1.17 ns, respectively, while for 2 and 2 + Fe3+ , the lifetimes were 1.13 and 0.63 ns, respectively. Additionally, the applicability of chemosensors 1 and 2 in detecting Fe3+ in live cells was demonstrated, with negligible observed cell toxicity.

Are Hansen solubility parameters relevant in predicting the post-treatment effect on polyamide-based TFC membranes?

This study investigates the impact of solvent post-treatment on polyamide-based thin film composite (TFC) membranes, specifically examining the effect on commercial nanofiltration (NF) and reverse osmosis (RO) membranes. Na2SO4 rejection and increase in pure water permeance (PWP) were considered as the output parameters. The disparity in Hansen solubility parameters (HSP) between the post-treatment solution and the polyamide layer of the TFC membrane, denoted by Ra, is well adapted to understand the enhancement in water permeance through the membranes upon treatment. Aqueous solutions of dimethylformamide with a Ra value of 4, acetonitrile with a Ra value of 8.3, and ethanol with a Ra value of 12.7 were used as the post-treatment solutions. Our experimental design, based on the Box-Behnken design of Response Surface Methodology, incorporates variables such as the concentration of the solvent in the solution (% v/v), Ra value, and treatment time (s). Our findings demonstrate that the effect of post-treatment on the TFC membranes is not governed by the Ra value. Notably, while the post-treatment with the aqueous solution of acetonitrile, 80% v/v for 30 s, had considerable effects on NF membranes (124.5% enhancement in PWP; reduction of 3.5% in Na2SO4 rejection), its impact on RO membranes was negligible. Several factors explain this discrepancy, including the limitations of the HSP model for composite polymers, the inaccuracy of the PWP or salt rejection as a swelling indicator, variations in the HSP values of the polyamide layers for different membranes, and possible modifications in the interface between the support membrane and the polyamide layer. In summary, our study provides insights into the complex interactions between solvents and composite membranes, indicating that HSP alone is not a decisive factor in predicting post-treatment effects on polyamide-based TFC membranes.