Types Of Side Chains Research Articles

Quaternary Ammonium Salt-Based Intrinsic Antibacterial Polyurethanes: Optimizing the Antibacterial Activity via Cationic Main- or Side-Chain Design in Hard Segments.

Thermoplastic polyurethanes (TPUs) are one of the most appealing materials with extensive applications in biomedical fields due to their versatile mechanical properties and excellent biocompatibility. In response to the escalating challenges of bacterial infections, it is desirable to obtain TPUs with intrinsic antibacterial activity, particularly for application in biomedical devices and public places. Herein, a cationic main-/side-chain structure regulation strategy in the TPU hard segment was adopted to introduce and optimize the antibacterial activity. This was achieved by synthesizing two types of quaternary ammonium salts (QAS)-containing chain extenders, i.e., N-methyl-N-alkyl-N,N-bis(2-hydroxyethyl) ammonium bromide (Mn, where n represents the N-alkyl chain length) and N,N-dimethyl-N-alkyl-N-2,3-propylene glycol (Dn), from N-methyldiethanolamine (MDEA) and 3-dimethylamino-1,2-propanediol (DMAD), respectively. Given the structural differences between Mn and Dn, main-chain-type PU-Mn and side-chain-type PU-Dn were subsequently obtained with QAS groups in the hard segment. The N-alkyl chain length, QAS content, and main-/side-chain types were systematically investigated to optimize bactericidal properties. The results revealed that a long N-alkyl chain (from C6 to C14) increased the antibacterial activity of the chain extenders and corresponding TPU films. Besides, side-chain-type PU-Dn films showed higher contact-active antibacterial activity than that exerted by the main-chain-type PU-Mn films. Remarkably, almost 100% of Staphylococcus aureus(S. aureus) could be killed by the PU-D14 film with a low QAS content (1.6 wt %). All the TPUs showed good thermal stability with a degradation temperature of 5% mass loss (Td,5%) above 300 °C. Moreover, the TPU films displayed excellent mechanical properties with the tensile strength at break varying from 20.7 to 47.5 MPa and ultimate elongation above 1000%. All of the intrinsic antibacterial films showed negligible hemolytic activities.

Investigating the synergistic effect of fish waste extract and KI on the corrosion inhibition of carbon steel in sulfuric acid solution

Biowaste has become a serious problem that can lead to serious environmental pollution and waste of resources if not handled properly. Waste materials are often high in proteins, which are easily extracted and hydrolyzed to provide an adequate quantity of amino acids. This indicates that biowastes can be used as green and efficient corrosion inhibitors (CIs). This work aimed to prepare fish waste extract (FWE) by acid hydrolysis with alkaline leaching using fish waste as the raw material. The results of the characterization analysis identified the presence of 17 amino acids, with Leucine, Phenylalanine, Methionine, and Alanine being the most abundant. FWE was then tested as a corrosion inhibitor (CI) for carbon steel in 0.5 mol/L H2SO4. Further, the effect of KI on the corrosion inhibition performance of FWE for carbon steel in 0.5 mol/L H2SO4 was systematically investigated by the weight loss method, electrochemical method, and surface analysis. The maximum corrosion inhibition efficiencies were 88.7 % and 63.9 % for the FWE and KI alone, and 97.10 % for the combination of FWE and KI. The synergistic coefficient study confirmed that the synergistic coefficients of the FWE and KI exceeded 1 across all concentration conditions, indicating a synergistic effect between them. The surface analysis results showed that the deterioration of carbon steel after adding the compounded CI was mild, and pitting and crevice corrosion was not observed. Theoretical calculations revealed the active reaction sites of four major amino acid molecules via quantum chemical and molecular dynamics simulations. The effect of different types of side chains and heteroatoms of amino acid molecules on their corrosion inhibition performance was elucidated to provide theoretical guidance for designing biowaste CIs.

High-Performance Black Copolymers Enabling Full Spectrum Control in Electrochromic Devices.

Black-to-transparent electrochromism is hailed as the holy grail of organic optoelectronics. Despite its potential, designing black electrochromic materials that fully absorb visible light remains a significant challenge. Electroactive materials that simultaneously possess excellent cyclic stability, fast switching times, and high coloration efficiency are rare. In this study, we successfully designed copolymers that fully absorb the entire visible spectrum byjudiciously selecting four types of monomers. We incorporated two types of polar side chains to synergistically enhance the ionic conductivity of the copolymers, thus improving the performance of electrochromic devices. Among these electrochromic devices, the P2-a device exhibits cycling stability exceeding 105 cycles, and the P2-c device demonstrates a coloring/ bleaching time of 0.82 s/0.86 s and achieves a coloration efficiency of 1078 cm²/C. This study proposes a strategy for designing and synthesizing high-performance black electrochromic copolymers.

Formation of Layered Liquid Crystal by Cooperation of Sidechain Array and Rigid Polyacetylene Mainchain

ABSTRACT An acetylene derivative monomer with a pyrimidine – type sidechain with three rings was synthesized by Steglich esterification. Polymerization of the acetylene derivative was then carried out with a rhodium complex. The acetylene monomer and mono-substituted polyacetylene derivative showed liquid crystals (LCs) because their tricyclic parts worked as a mesogenic core. The monomer as an acetylene derivative showed smectic with a tilted structure in the LC aggregation form. The mono-substituted polyacetylene bearing mesogen via short alkyl spacer showed lyotropic and thermotropic LCs of the smectic phase, although generally flexible long alkyl spacer from the main chain connected to sidechain mesogen is required for exhibiting liquid crystal in sidechain type polymer liquid crystals. In the present study, rigid mainchain aligns the sidechain mesogen array to form non-tilted LC. Properties of LCs were evaluated by various analytical techniques, including polarizing optical microscopy. Structural properties were evaluated by nuclear magnetic resonance spectroscopy, gel permeation chromatography, infrared spectroscopy, and ultraviolet – visible absorption spectroscopy.

Side-chain type PPO based anion exchange membrane with steric hindrance containing dual conduction sites

Appropriate addition of cation transport sites while maintaining the good mechanical properties of anion exchange membranes (AEMs) can effectively improve the hydroxide ion conductivity. Therefore, a series of poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) based side-chain type AEMs containing dual conduction sites are successfully prepared. The 4-(4-dimethylaminostyryl)-1-methylpyridinium (DASP) side chains are grafted to brominated PPO at different ratios, which is confirmed by Fourier transform infrared spectroscopy (FT-IR). Analysis of the microscopic morphology reveals a distinct microscopic separation pattern of hydrophilic/hydrophobic regions, which provides efficient channels for the transport of hydroxide ions. The ionic conductivity of the PPO-DASP13 membrane reaches 89.97 mS/cm at 80 °C, which is benefited from the double cationic groups contained in the side chains, providing more conduction sites for hydroxide ions. Meanwhile, the tensile strength of membranes range from 17.83 MPa to 29.38 MPa, which have good mechanical properties. The ionic conductivity of all membranes retain about 70 % after a 800 h long-term alkali resistance test, which is related to the steric hindrance contained in the side chain structure and the conjugated system. Furthermore, the single cell based on PPO-DASP13 membrane with the highest ionic conductivity achieves a peak power density of 347.7 mW/cm2 in H2-air (CO2-free) at 60 °C.

Side-Chain Type Ferrocene Macrocycles.

A class of side-chain type ferrocene macrocycles with a radially conjugated system is introduced in this study. The stereo configurations of these ferrocene rings were determined through single-crystal X-ray diffraction analysis. Notably, in the solid state, the ferrocene rings exhibit a distinctive herringbone stacking pattern imposed by a ferrocene-to-ring host-guest interaction. Through UV-vis absorption spectroscopy, electrochemical measurements, and theoretical calculations, valuable insights into the electronic properties of these rings were obtained. In addition, the single crystal of macrocycle A 2 B demonstrates a second-order nonlinear optical response. As a class of organometallic nanorings, this work holds great potential for further exploration in the fields of organometallic chemistry, molecular electronics, and host-guest chemistry.

Preparation and properties of PPO-based anion exchange membranes with flexible side chains for fuel cells

Poor alkali resistance and low ionic conductivity are the crux of the matter that hinder the commercialization applications of anion exchange membranes (AEMs). Here, we designed and synthesized a range of poly(phenylene oxide) (PPO)-based AEMs with benzyl free side-chain type. After that, the influences of different cationic functional groups, such as quaternary ammonium, imidazole and piperidine, on the membrane performances were examined systemically. The introduction of ether bond-containing side chains to build micro-phase separation structures enhanced the conductivity of AEMs (64 mS·cm−1 at 80 °C). At the same time, the side-chain without benzyl structures effectively avoids the influence of electron withdrawing groups on PPO main chains. Moreover, the steric hindrance effect of the benzene ring can further alleviate the attack of OH−, thereby improving the alkali resistance of the membrane. Molecular dynamics simulations revealed that a well-developed hydrogen bonding network was formed between ether linkages and water molecules in the side-chain structures, which enhanced the electrical conductivity of the membrane. Meanwhile, the prepared membranes owned a good water uptake and a certain dimensional stability. These results provide a basis for the subsequent enhancement of membrane performances.

Leaf developmental patterns of two species of Baccharis (Asteraceae): an analysis based on cell wall pectins

The cell wall plays a primary role in plant growth, which is regulated by cellulose microfibrils, proteins, and pectins. Regarding pectins, the rate of homogalacturonan (HG) methylesterification and the type of rhamnogalacturonan side chains can mediate leaf development. Herein, we evaluated pectic compounds of the cell walls by immunocytochemistry during the leaf development of Baccharis dracunculifolia DC. and Baccharis platypoda DC. Leaves in different maturation stages (from leaf bud to 9th node) were collected in a rupestrian field and fixed in formalin, acetic acid for anatomical and immunocytochemical analyses using monoclonal antibodies (JIM5, JIM7, LM5, and LM6). Both species showed similar anatomical structures based on peculiar cell wall pectic matrices. Baccharis platypoda leaves reach precocious maturation in the 3rd node, while B. dracunculifolia reaches maturation in the 6th node. These results seem to be related to HGs already de-methylesterified in the leaf primordia located in the leaf bud of B. platypoda. Epitopes of (1→5) α-l-arabinan occurred only in the collenchyma of B. platypoda, supporting cell wall stability. (1→4) β-D-galactans showed different fluorescence intensities in the two species, which changed during leaf development. The different rates of leaf tissue maturation between the two Baccharis species are influenced by variations in the pectic compounds of the cell walls, especially regarding the rate of HG methylesterification.

Overcoming the Trade‐off Between Efficient Electrochemical Doping and High State Retention in Electrolyte‐Gated Organic Synaptic Transistors

AbstractTo achieve superior device performance such as low threshold voltage Vth, high maximum on‐current Ion,max, and long retention time in electrolyte‐gated organic synaptic transistors, efficient electrochemical doping and high state retention are essential. However, these characteristics generally show a trade‐off relationship. This work introduces an effective strategy to increase retention time while promoting efficient electrochemical doping. The approach involves blending two polymer semiconductors (PSCs) that have the same backbone but different types of side chains. Polymer synaptic transistors (PSTs) with the blend film showed the lowest Vth, highest Ion,max, longest retention time, and superior cyclic stability compared to PSTs that used films containing only one of the PSCs. The improvement in electrical and synaptic properties achieved through the blend strategy is consistently reproducible and comprehensive. It is attributed this improvement to the increased redox activity and constrained morphological changes observed in the blended PSCs during electrochemical doping, as confirmed by several electrochemical characterizations. This work is the first to increase retention time in PSTs without increasing the crystallinity of polymer film or sacrificing the electrochemical doping efficiency, which has been regarded as an unavoidable compromise in this field. This method provides an effective way to tune synaptic properties for various neuromorphic applications.

Programming co-assembled peptide nanofiber morphology via anionic amino acid type: Insights from molecular dynamics simulations.

Co-assembling peptides can be crafted into supramolecular biomaterials for use in biotechnological applications, such as cell culture scaffolds, drug delivery, biosensors, and tissue engineering. Peptide co-assembly refers to the spontaneous organization of two different peptides into a supramolecular architecture. Here we use molecular dynamics simulations to quantify the effect of anionic amino acid type on co-assembly dynamics and nanofiber structure in binary CATCH(+/-) peptide systems. CATCH peptide sequences follow a general pattern: CQCFCFCFCQC, where all C's are either a positively charged or a negatively charged amino acid. Specifically, we investigate the effect of substituting aspartic acid residues for the glutamic acid residues in the established CATCH(6E-) molecule, while keeping CATCH(6K+) unchanged. Our results show that structures consisting of CATCH(6K+) and CATCH(6D-) form flatter β-sheets, have stronger interactions between charged residues on opposing β-sheet faces, and have slower co-assembly kinetics than structures consisting of CATCH(6K+) and CATCH(6E-). Knowledge of the effect of sidechain type on assembly dynamics and fibrillar structure can help guide the development of advanced biomaterials and grant insight into sequence-to-structure relationships.

Phosphorylated poly(ethylene-co-vinyl alcohol) doping for enhanced proton conductivity and mechanical properties of side chain–type sulfonated poly(aryl ether ketone) proton-exchange membranes

Phosphorylated poly (ethylene-co-vinyl alcohol) (PEVOH) was synthesized and blended with side chain–type sulfonated poly (aryl ether ketone) (SPAEK) to prepare SPAEK proton-exchange membranes with improved physicochemical and electrochemical properties. The results indicate that PEVOH doping helps improve the mechanical properties and proton conductivity of the membranes. The addition of PEVOH not only enhances proton transport but also provides proton transport channels for the membranes at a high temperature and low humidity, leading to excellent fuel cell performance and low ohmic resistance. The interaction between sulfonic acid and phosphonic acid side chain groups leads to the excellent nano-phase separation under microscopic morphology. This forms a large hydrogen bonding network between the acidic and amphoteric groups, which facilitates proton transport at low relative humidities.

Phosphates Induced H-Type or J-Type Aggregation of Cationic Porphyrins with Varied Side Chains.

Non-covalent interactions have been extensively used to fabricate nanoscale architectures in supramolecular chemistry. However, the biomimetic self-assembly of diverse nanostructures in aqueous solution with reversibility induced by different important biomolecules remains a challenge. Here, we report the synthesis and aqueous self-assembly of two chiral cationic porphyrins substituted with different types of side chains (branched or linear). Helical H-aggregates are induced by pyrophosphate (PPi) as indicated by circular dichroism (CD) measurement, while J-aggregates are formed with adenosine triphosphate (ATP) for the two porphyrins. By modifying the peripheral side chains from linear to a branched structure, more pronounced H- or J-type aggregation was promoted through the interactions between cationic porphyrins and the biological phosphate ions. Moreover, the phosphate-induced self-assembly of the cationic porphyrins is reversible in the presence of the enzyme alkaline phosphatase (ALP) and repeated addition of phosphates.

A simple approach for fabrication of low-temperature processible inverted organic solar cells

Small molecule electrolytes (SMEs) based on naphthalene diimide with various types of side chains, such as tosylate anion and zwitterion were synthesized for photovoltaic application as the cathode interlayer. These materials utilizedthe side chains to produce a beneficial interface dipole. With PM6:Y6BO as the active layer, the device based on NDIN-BS exhibited a PCE of 14.5%, which is almost the same as the PCE of the ZnO-based device (15.0%). The device based on NDIN-OTs exhibited a lower PCE of 14.2%, which mainly resulted from the significant decrease of the Jsc, but exhibit a higher FF due to the better contact with the active layer. This outcome showed that SMEs are suitable candidates to adjust the work function of ITO and provide an alternative to the ZnO interlayer, which relies on proper monitoring of the sol–gel transition by high annealing temperatures as high as 200 °C, leading to simplifying the manufacture of cost-effective OSCs.

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and thermal stability

Rosin side chain type catalyst-free vitrimers with high cross-link density, mechanical strength, and thermal stability

Utility of a Systematic Approach to Selecting Candidate Prodrugs: A Case Study Using Candesartan Ester Analogues

Development of prodrugs is a useful strategy to overcome some disadvantages of candidate drugs. Recently, we established a systematic approach to selecting appropriate prodrugs, and validated the utility of this approach using oseltamivir analogues. In this study, the utility of the approach was further examined using candesartan cilexetil and 20 kinds of its analogues having various types of side chain as model compounds. Log D values of analogues (2.5 to 4.7) were higher than that of candesartan (1.0), their active metabolite, and the results were reasonable for the purpose of improving permeability of candesartan. The analogues tended to be more soluble in artificial intestinal fluids than in artificial gastric fluid, owing to their acidic physicochemical characteristics. Their membrane permeabilities were not correlated with log D values, which can be attributed to the metabolism in Caco-2 cells used in this system. In human hepatocytes and enterocytes, 11 out of the 20 analogues were immediately hydrolyzed to candesartan, and species differences were observed in the hydrolysis efficiency. This study confirmed the utility of the systematic approach for selection of appropriate prodrugs that could be proceeded to in vivo pharmacokinetics study, with selection of suitable experimental animals.

Chemically Acylated tRNAs are Functional in Zebrafish Embryos.

Genetic code expansion has pushed protein chemistry past the canonical 22 amino acids. The key enzymes that make this possible are engineered aminoacyl tRNA synthetases. However, as the number of genetically encoded amino acids has increased over the years, obvious limits in the type and size of novel side chains that can be accommodated by the synthetase enzyme become apparent. Here, we show that chemically acylating tRNAs allow for robust, site-specific incorporation of unnatural amino acids into proteins in zebrafish embryos, an important model organism for human health and development. We apply this approach to incorporate a unique photocaged histidine analogue for which synthetase engineering efforts have failed. Additionally, we demonstrate optical control over different enzymes in live embryos by installing photocaged histidine into their active sites.

Fused-ring electron acceptors with a macrocyclic side chain

Fused-ring electron acceptors featuring a macrocyclic side chain were synthesized and afforded power conversion efficiencies up to 14.68% in organic solar cells.

تحضير وتشخيص كاسرات أستحلاب جديدة من بوليمرات طبيعية وصناعية

This research included the preparation and characterization of new demulsifies from natural and synthetic polymers of chitosan and polyvinyl alcohol that are environmentally friendly and at the same time have high efficacy comparable to emulsifiers. imported foreign. The prepared compounds were examined using infrared spectroscopy and nuclear magnetic resonance spectroscopy, and all the spectral signals of the polymers were in good agreement with the chemical composition of the polymers. And the melting and decomposition that occur on polymers at high temperatures. The effect of the length and type of side chain in the compositions of polymers on the process of water separation of oil emulsions was studied, and they had an important impact on the levels of water separation. The solubility behavior of polymers was also known, so that there was a solubility difference in Different organic solvents according to the type of the side chain of a hydrocarbon nature, and the best solubility of the prepared polymers was a solvent (dimethyl sulfoxide). The best polymerization time was found (12) h, as well as the best temperature at which polymerization takes place is (70 °C) and the prepared emulsion was compared with The commercial emulsifier was evaluated for its efficiency in separating water from crude oil (crude oil Basra) and compared to the commercial emulsifier, it was more efficient than the commercial one in separating water from oil.

Sulfonated poly (ether ketone sulfone) composite membranes containing ZIF-67 coordinate graphene oxide showing high proton conductivity and improved physicochemical properties

In this study, a sulfonated poly (ether ketone sulfone) with multiple sulfonic acid groups was prepared and named as MSP, where the multiple sulfonic acid groups in the polymer were located on its side chains of uneven length. And a series of hybrid membranes were prepared by introducing organic–inorganic fillers (ZIF-67/GO) into this side chain type polymer matrix. Among them, ZIF-67 was chemically grafted onto the GO sheet through coordination between Co+ and the carboxyl group of GO, bound to GO and grown uniformly. The ZIF-67/GO and hybrid membranes were characterized by FT-IR, XRD, SEM, AFM and 1H NMR. The hybrid membranes exhibited increasingly high proton conductivity from MSP (0.0876 S cm−1) to MSP-1 % ZIF-67/GO (0.1426 S cm−1) at 100 °C and 100 % relative humidity. Moreover, the hybrid membranes have excellent chemical stability. The results indicated that ZIF-67/GO was important for constructing of proton transport channels, and the prepared hybrid membranes showed great potential for application in PEM.

Total Synthesis of Geranyl-Resorcinols Isolated from Mushrooms of Genus Hericium

AbstractThis Short Review covers the total synthesis of tetraketide-based meroterpenoids, i.e. geranyl-resorcinols, isolated from the mushrooms of genus Hericium. Some of these compounds are believed to be involved in the unique health-promoting effects of Hericium erinaceus. Herein, more than seventy natural products identified so far have been classified into seven-types based on both assumed biosynthetic pathways and chemical structures, and the successful total syntheses are summarized according to the structural type.1 Introduction2 Pioneering Synthetic Study3 Total Synthesis of Geranyl-Resorcinol with a Geranyl Side Chain (Types 1, 3, and 6)4 Total Synthesis of Geranyl-Resorcinol with an Oxidized Geranyl-Derived Side Chain (Types 2, 4, and 7)5 Conclusion