Functional Amino Research Articles

Investigation on growth, growth kinetics and characterization of L-valine L-valinium perchlorate monohydrate single crystal

The ultimate focus of this paper is on nucleation and growth kinetics, structural and dielectric behavior of l-valine l-valinium perchlorate monohydrate (LVPM) single crystal. LVPM single crystals were grown by conventional slow evaporation technique at room temperature. Salient nucleation parameters, essential for the growth of good quality crystal were estimated with the help of solubility curve and Classical Nucleation Theory (CNT). Single Crystal X-ray Diffraction (SC-XRD) analysis reveals that the synthesized crystal (LVPM) possesses monoclinic structure with lattice parameters as a = 11.227 Å, b = 5.82 Å, c = 13.08 Å, α = γ = 90º and β = 91º. The above results were also confirmed by powder XRD study. The structure of the grown crystal was analyzed by using SHELXT-2014/7 program. It is found that grown crystal belongs to non-centrosymmetric space group P21. All the functional groups and also carboxyl and amino functional groups of LVPM crystal were identified and confirmed by Fourier Transform Infra-red (FTIR) spectroscopy. The molecular structure of the grown crystal and in particular, the presence of amino group was discussed by using 1H and 13C Nuclear Magnetic Resonance (NMR) spectra. The low values of dielectric constant and dielectric loss at higher frequencies indicate that the grown crystal enhances the Second Harmonic Generation (SHG) efficiency. The activation energy of the grown crystal was estimated as 0.1433 eV from AC conductivity study. Kurtz and Perry powder experiment was performed to explore the Nonlinear Optical (NLO) properties of LVPM and its SHG efficiency was found 1.5 times of KDP (1.5’ KDP). The grown material was also found possessing SHG efficiency nearly five times higher than most of the l-arginine compounds. Since the grown material belongs to non-centrosymmetric group and exhibits improved structural, NLO and dielectric behavior, the material will be useful in optoelectronic devices, fiber optic communication, computing, optical switching, image reconstruction, optical storage technology, 3D-images, etc.

A PEGylated Chitosan as Gel Polymer Electrolyte for Lithium Ion Batteries.

Due to their safety and sustainability, polysaccharides such as cellulose and chitosan have great potential to be the matrix of gel polymer electrolytes (GPE) for lithium-based batteries. However, they easily form hydrogels due to the large numbers of hydrophilic hydroxyl or amino functional groups within their macromolecules. Therefore, a polysaccharide-based amphiphilic gel, or organogel, is urgently necessary to satisfy the anhydrous requirement of lithium ion batteries. In this study, a PEGylated chitosan was initially designed using a chemical grafting method to make an GPE for lithium ion batteries. The significantly improved affinity of PEGylated chitosan to organic liquid electrolyte makes chitosan as a GPE for lithium ion batteries possible. A reasonable ionic conductivity (1.12 × 10-3 S cm-1) and high lithium ion transport number (0.816) at room temperature were obtained by replacing commercial battery separator with PEG-grafted chitosan gel film. The assembled Li/GPE/LiFePO4 coin cell also displayed a high initial discharge capacity of 150.8 mA h g-1. The PEGylated chitosan-based GPE exhibits great potential in the field of energy storage.

Amino functionalization of magnetic multiwalled carbon nanotubes with flexible hydrophobic spacer for immobilization of Candida rugosa lipase and application in biocatalytic production of fruit flavour esters ethyl butyrate and butyl butyrate

Amino functionalization of magnetic multiwalled carbon nanotubes with flexible hydrophobic spacer for immobilization of Candida rugosa lipase and application in biocatalytic production of fruit flavour esters ethyl butyrate and butyl butyrate

Photocatalytic Modular Cyanoalkylamination of Alkenes Involving Two Different Iminyl Radicals.

The modular cyanoalkylamination of alkenes using bench-stable and easy-to-handle α-imino-oxy acid oxime esters as difunctional reagents creates new synthetic avenues. A metal-free photosensitization protocol for the installation of both amino and cyanoalkyl functionalities onto alkene feedstocks in a single step via two differently reactive nitrogen-centered radicals was developed via energy-transfer catalysis. Excellent functional group tolerance and mild reaction conditions also render this protocol suitable for the cyanoalkylamination of pharmaceutically relevant molecule-derived alkenes.

Effect of CaS Nanostructures in the Proliferation of Human Breast Cancer and Benign Cells In Vitro.

We report on the effect of naked CaS nanostructures on the proliferation of carcinoma cancer cells and normal fibroblasts in vitro. The CaS nanostructures were prepared via the microwave-mediated decomposition of dimethyl sulfoxide (DMSO) in the presence of calcium acetate . Light scattering measurements revealed that dispersions contain CaS nanostructures in the size range of a few Å to about 1 nanometer, and are formed when DMSO is decomposed in the presence of . Theoretical calculations at the DFT/B3LYP/DGDZVP level of theory on clusters ( , and 4) are consistent with clusters in this size range. The absorption spectra of the CaS nanostructures are dominated by strong bands in the UV, as well as weaker absorption bands in the visible. We found that a single dose of CaS nanoclusters smaller than 0.8 nm in diameter does not affect the survival and growth rate of normal fibroblasts and inhibits the proliferation rate of carcinoma cells in vitro. Larger CaS nanostructures, approximately (1.1 ± 0.2) nm in diameter, have a similar effect on carcinoma cell proliferation and survival rate. The CaS nanoclusters have little effect on the normal fibroblast cell cycle. Human carcinoma cells treated with CaS nanocluster dispersion exhibited a decreased ability to properly enter the cell cycle, marked by a decrease in cell concentration in the G0/G1 phase in the first 24 h and an increase in cells held in the SubG1 and G0/G1 phases up to 72 h post-treatment. Apoptosis and necrotic channels were found to play significant roles in the death of human carcinoma exposed to the CaS nanoclusters. In contrast, any effect on normal fibroblasts appeared to be short-lived and non-detrimental. The interaction of CaS with several functional groups was further investigated using theoretical calculations. CaS is predicted to interact with thiol ( ), hydroxide ( ), amino ( ), carboxylic acid ( ), ammonium ( ), and carboxylate ( ) functional groups. None of these interactions are predicted to result in the dissociation of CaS. Thermodynamic considerations, on the other hand, are consistent with the dissociation of CaS into ions and in acidic media, both of which are known to cause apoptosis or cell death. Passive uptake and extracellular pH values of carcinoma cells are proposed to result in the observed selectivity of CaS to inhibit cancer cell proliferation with no significant effect on normal fibroblast cells. The results encourage further research with other cell lines in vitro as well as in vivo to translate this nanotechnology into clinical use.

Amino Functionalization Approach to Synthesis of Carbon Supported Intermetallic Platinum-Based Alloy Catalysts for Fuel Cell Application

Platinum (Pt) is a critical element in making electrocatalysts for oxygen reduction reaction (ORR) occurring at the cathode of polymer electrolyte membrane fuel cells (PEMFCs). To address the Pt abundance issue and to enhance Pt catalysis, Pt is often alloyed with another transition metal M (i.e. M = Fe, Co, and Ni). Ordered intermetallic PtM alloys are considered as one of the most promising candidates to achieve both high activity and stability in practical fuel cell applications. The transition metals in ordered intermetallic PtM alloys occupy specific sites, and are stabilized by both metallic and ionic bonding. Ordered intermetallic structures are formed via high temperature (>600 °C) annealing of disordered PtM alloys, as the atomic ordering is a thermodynamically driven process. However, the high temperature annealing inevitably leads to the migration and agglomeration of the nanoparticles forming randomly alloyed particles with poor dispersion and broad size distributions, due to weak adhesions to the carbon support under typical processing conditions. To prevent this coalescence during annealing, protective coating of the nanoparticles with inorganic shells or physical barriers has been suggested. However, these studies were limited to the synthesis of intermetallic nanoparticles on carbon supports at low metal loadings, or require an additional step of removing the coating layer from the surface of the nanoparticles to expose the active sites. Thus, it is essential to develop a general approach that can produce highly dispersed, structurally ordered nanoparticles while achieving controls over the size and size distribution. We propose to use the functionalized carbon supports to control PtM alloy nanoparticle size and prevent nanoparticles from aggregating during the high temperature annealing through improving the metal-support interactions. A strong electrostatic attraction between the negative charge from Pt precursor (PtCl6 2 -) and positive charge from the amino groups (C-NH2+) on the surface of the functionalized carbon will be established during the wet impregnation synthesis. Such bonds will help to make the PtM nanoparticle size smaller and more uniformly distributed over the surface of support. The ordered intermetallic 30 wt.% PtCo/KB-NH2 catalyst demonstrated an average size of 2.7 nm and uniform size distribution. In addition, 30 wt.% PtCo/KB-NH2 catalyst exhibited a mass activity of 535 A/gPt (H2/O2) and a rated power density of 1.05 W/cm2 at 0.67 V (H2/air), meeting the DOE targets.

Changes of the physicochemical properties of extracellular polymeric substances (EPS) from Microcystis aeruginosa in response to microplastics

Microplastics (MPs) are ubiquitous in aquatic ecosystems and can significantly influence the growth, aggregation and functions of phytoplankton biomass. However, variations in the extracellular polymeric substances (EPS) of phytoplankton in terms of compositions and structures in response to MPs were still not reported. In this study, EPS matrix of Microsystis aeruginosa was applied and fractionated into loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) fractions, with the time-dependent changes in response to different concentrations (10, 100 and 500 mg/L) of MPs being explored via using the fluorescence excitation emission matrix coupled with parallel factor (EEM-PARAFAC) and two-dimensional Fourier transform infrared correlation spectroscopy (2D-FTIR-COS) analysis. Results showed that 500 mg/L of MP concentration significantly inhibited Microcystis growth by 30.5% but enhanced EPS secretion. In addition, organic composition in LB-EPS and TB-EPS varied differently in response to increased MP exposure, as the ratio of polysaccharide/protein increased in the TB-EPS but decreased in LB-EPS. Further analysis revealed obvious heterogeneities in organic component variations in response to MPs, as the C–O functional groups and glycosidic bonds in the TB-EPS preferentially responded, which lead to the domination of polysaccharides and humus substances; while the carbonyl, carboxyl and amino functional groups in the LB-EPS exhibited a preferential response, which caused the enhanced percentage of the tryptophan-like proteins. In addition to organic compositions, the aromaticity, hydrophobicity and humification in the LB-EPS fraction increased with enhanced MP exposure, which, as a result, may influence the ecotoxicological risk of MPs. Therefore, Microcystis can dynamically adjust not only the EPS contents but also the compositions in response to MPs exposure. The results can improve our understanding on the eco-physiological impact of phytoplankton-MP interaction in aquatic environment, and indicate that the dose-dependent and long-term effects of MPs on phytoplankton should be considered in future study.

Enantio‐separation of (±)‐ibuprofen racemic mixture using functionalized molecularly imprinted resorcinol formaldehyde resin

AbstractAn (S)‐ibuprofen (S‐IP) enantio‐selective resin sorbent with amino functionality has been synthesized and successfully used in the enantio‐separation of (±)‐IP racemic mixture. An amide derivative (S‐IP‐ARS) of 4‐aminoresorcinol and the S‐IP enantiomer was first prepared. The obtained S‐IP‐ARS derivative was mixed with resorcinol and formaldehyde to undergo an acid‐catalyzed condensation polymerization reaction that resulted in a polymer resin material containing the S‐IP enantiomeric species within its construction. Upon alkaline hydrolysis and following acidification, S‐IP is detached from the polymeric body, leaving cationic enantio‐selective spaces that can fit with the configuration of S‐IP during the recombination process. The obtained S‐IP molecularly imprinted resin along with the monomeric precursor was examined using elemental analysis, NMR and Fourier transform infrared techniques in order to confirm the performed chemical reactions. Moreover, the resin surfaces were visualized using scanning electron microscopy to account for the morphological changes. Also, the prepared resin particles were successfully utilized in the chiral separation of (±)‐IP racemic mixture using a column technique that indicated promising separation results during both the first loading run, which exhibited 58% enantiomeric excess (ee) belonging to R‐IP, and the second elution run, which exhibited 78% ee belonging to S‐IP. © 2022 Society of Industrial Chemistry.

Nickel Nanoparticles Immobilized on Pristine Halloysite: An Outstanding Catalyst for Hydrogenation Processes

AbstractNickel nanoparticles (NiNPs) immobilized on halloysite‐based supports were straightforwardly synthesized and fully characterized by different techniques with the purpose of evaluating the catalytic performance of these as‐prepared composite materials as catalysts in hydrogenation reactions. Thus, halloysite bearing amino (HAL‐NH2) and ammonium (HAL‐NEt3) groups led to less active catalytic materials in comparison with unfunctionalized halloysite supports, probably due to relative strong metal‐support interactions with amino and tetraalkylammonium functions, consequently hindering the interaction of unsaturated substrates at the surface of the catalytic material. Despite NiNPs supported on pristine halloysite provided merely agglomerates, NiNPs stabilized by quinidine on unfunctionalized halloysite (NiC) proved to be a highly effective and versatile catalyst operating at relative low temperature (25–100 °C) and metal loading (1–20 mol %Ni), very well‐adapted to reduce a large range of functions (alkenes, alkynes, ketones, aldehydes, nitro…). Moreover, NiC was able to selectively reduce substrates from biomass to yield high value‐added products, such as squalane, saturated fatty acids, furfuryl alcohol and γ‐valerolactone.

Amino-functionalized 3D crosslinked Ti3C2Tx nanosheets for highly efficient UO22+ and ReO4− immobilization simultaneously from aqueous solutions

Construction of the multifunctional Ti3C2Tx for efficient extraction of radioactive metal cations and anions from radioactive waste simultaneously remained challenging. Decorating Ti3C2Tx into multifunctional materials with controllable and desired properties was an efficient strategy for eliminating UO22+ and ReO4−. In this work, a novel amino-functionalized 3D crosslinked Ti3C2Tx nanosheets (N-CTC) were designed by covalent bonding crosslinking method, followed by a facile hard template to prevent the delamination Ti3C2Tx nanosheets from stacking. Introducing amino functional groups and adjusting surface charge of N-CTC considerably enhances the removal of simultaneously UO22+ and ReO4− from aqueous solutions. Impressively, N-CTC exhibited the exceptional trapping capacities toward UO22+ (550.71 mg/g) and ReO4− (105.01 mg/g), which were significantly superior than that of the pristine Ti3C2Tx nanosheets. More importantly, N-CTC also possessed fast rapidly and recyclable UO22+/ReO4− extraction in different artificial water samples. The elimination mechanism was clearly visualized by spectral analysis, uncovering UO22+ removal was abided by chelation effect, whereas the ReO4− adsorption was determined by both inner-sphere complexation and electrostatic interaction. The present results illustrate an effective strategy to design functionalized 3D crosslinked Ti3C2Tx nanosheets with effectively extraction of radioactive metal cations and anions from wastewater.

Green synthesis of carbon dots from elm seeds via hydrothermal method for Fe3+ detection and cell imaging

• Carbon dots were synthesized by hydrothermal method using elm seed as carbon source. • The CDs were selectively quenched by Fe 3+ and can be used as sensitive Fe 3+ sensor. • The CDs were good biocompatible and could label HepG2 cells with blue fluorescence. Hydrothermal method to prepare biomass-based carbon dots (CDs) is environmentally-friendly and it can convert useless waste into valuable materials. In this work, we aimed to use natural siberian elm ( Ulmus pumila L.) seeds as carbon source to synthesize CDs by hydrothermal method. The obtained CDs were characterized by TEM, FTIR and XPS methods, founding they were near-spherical in shape with an average diameter of 3.83 nm. The CDs were mainly composed by carbon, nitrogen and oxygen, which formed the various hydrophilic functional carboxyl, hydroxyl, amino and amide groups on the surface. In addition, the CDs could emit bright blue fluorescence under ultraviolet illumination with excellent pH stability and photostability. Among various metal ions, the CDs could be selectively quenched by Fe 3+ . The degree of quenching was linearly related to the concentration of Fe 3+ , indicating they could be used for Fe 3+ detection. Finally, the CDs were proven to be good biocompatible by MTT assay and they could effectively label HepG2 cells with bright blue fluorescence. In summary, the CDs could be potentially applied as Fe 3+ sensors for water pollution detection and agents for cell imaging.

Stable and reusable acrylic ion-exchangers. From HMIs highly polluted tailing pond to safe and clean water

The application of several ion-exchange resins (IExR) with amino and amphoteric functionalities in batch retention of heavy metal ions (HMIs) (Cu(II), Fe(II), Mn(II), Zn(II)) from mono- and multicomponent simulated waters and from real polluted water collected from tailings pond of Tarnita (Suceava, Romania) sterile dump is deeply herein explored. The tested resins exhibited high sorption capacities, as evaluated by atomic absorption spectrometry, results supported by infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The effect of pH on the IExR sorption capacity in competitive condition evidenced the optimum pH where IExR sorption efficiency is maximum. Reutilization of IExR in six consecutive sorption/desorption/regeneration cycles showed their renewable sorption properties. Wheat germination tests demonstrated that the Tarnita collected water had a high toxic effect whereas the resulted supernatant after batch sorption was nontoxic. The study shows that HMIs content after IExR sorption is under the admitted maximum level for surface water, and represents an important step on the efforts to solve the environmental problem in Tarnita area, by removing the main contaminants found in the local river water.

Introduction of the Functional Amino Group at the meso Position of Cy3 and Cy5 Dyes: Synthesis, Stability, Spectra and Photolysis of 4‐Amino‐1‐diazo‐2‐butanone Derivatives**

AbstractSearching for photoconvertible or photoactivatable dyes, we considered trimethine (Cy3) and pentamethine (Cy5) fluorophores with a 4‐amino‐1‐diazo‐2‐butanone fragment (H2N(CH2)2COCH=N2) attached to the meso (γ) position of the polymethine chain via the amino group. The Cy3 derivative was prepared. All Cy5 derivatives with the basic amino group at this position decomposed with breaking the polymethine chain. However, amino‐squaraine based Cy5 dyes were found to be stable and accessible. Photolysis of Cy3 and squaraine‐based Cy5 dyes with a 4‐amino‐1‐diazo‐2‐butanone fragment was accompanied with Wolff rearrangement and led to pyrrolidones (in methanol and aprotic solvents) formed via intramolecular cyclization of the intermediate ketenes. In aqueous acetonitrile, ketenes reacted with water and gave carboxylic acids. Both products were non‐fluorescent, though the model Cy5 dyes (without the squaraine fragment) with acylated amino and N‐methylamino groups were found to be fluorescent.

Removal of Hg2+ in wastewater by grafting nitrogen/sulfur-containing molecule onto Uio-66-NH2: from synthesis to adsorption studies.

The remediation of heavy metal deserves to be on the agenda, with the adsorbent design bearing the brunt of it. In this study, the molecule (4, 6-diamino-2-mercaptopyrimidine, DMP)containing thiol (-SH) and amino (-NH2) functional groups was grafted onto Uio-66-NH2, and a composite metal-organic framework nanomaterial (Zr(NH2)-DMP) was synthesized via a facile post-modification scheme. The morphological characteristics and structural features of the modified adsorbent were characterized by XRD, FT-IR, FE-SEM, EDS, BET, and XPS. The characterization results verified that the post-modification scheme was successfully achieved. The adsorption experiments were carried out to investigate the removal performance of the Zr(NH2)-DMP towards Hg2+ under different influencing parameters. The maximum adsorption capacity of 389.4mg/g was obtained, and the adsorption equilibrium was achieved within 30min at pH 6 at room temperature. Adsorption thermodynamic study indicated that the adsorption process was exothermic and spontaneous. The Zr(NH2)-DMP exhibited excellent selectivity for Hg2+, and also has the potential to remove Cu2+, Fe2+, and Zn2+ ions. The introduction of Cl- inhibited the removal of Hg2+ due to the formation of mercuric chlorides (removal efficiency reduced from 97.8 to 95.6%). The removal efficiency of up to 86.7% was obtained after four cycles. The Langmuir isotherm and Pseudo-second kinetic were more suitable for fitting the adsorption process of Hg2+ by Zr(NH2)-DMP. The main removal mechanism could be attributed to the chelation between Hg2+ (soft acid) and nitrogen/sulfur (soft base) elements. These findings convinced that the successful synthesis of Zr(NH2)-DMP provides an option for Hg2+ removal from wastewater.

Electrocatalytic hydrogen evolution over micro and mesoporous cobalt metal-organic frameworks

The development of water electrolysis devices is crucial for the sustainable production of green hydrogen fuel. However, the slow kinetics and high overpotential are key shortfalls for hydrogen production during the half-cell hydrogen evolution reaction (HER) and significantly reduce the overall efficiency. Here we fabricated two micro- and mesoprorous cobalt MOFs [Co(BDC)(DMSO)(DMF)]n and [Co(NH2-BDC)(DMSO)(DMF)]n (labeled Co-1 and Co-2, respectively) by using a benezenedicarboxylic acid (H2BDC) linker and its amine-derivative (H2N-BDC). The chemical functionalization of organic linkers in MOFs enhances catalytic activity by providing Lewis acidity or basicity, potentially enhancing electrocatalytic activity. Co-1 MOF ([Co(BDC)(DMSO)]n) had a rod-like morphology, while Co-2 MOF ([Co(NH2-BDC)(DMSO)]n) was in the form of two-dimensional sheets. After characterizing the materials using PXRD, SEM-EDX, XPS, TGA, FTIR, and gas sorption, we explored the electrocatalytic activity of the MOFs for hydrogen evolution reaction (HER). The presence of surface amino functions slightly improved HER activity of cobalt MOFs in terms of overpotential (η from 0.217 V to 0.215 V @ 25mAcm-2) and Tafel slope (from 95mVdec−1 to 91mVdec−1). However, Co-2 showed better stability and high Faradaic efficiency (97 %), which we attribute to morphological features, mesoporosity, and the presence of basic surface functionalities.

High-Density Gold Nanoparticles Implanted on Mg/Fe LDH Nanoflowers Assisted Lateral Flow Immuno-Dipstick Assay for Visual Detection of Human Epididymal Protein 4.

The timelier and more accurate the diagnosis of the disease, the higher the patient’s survival rate. Human epididymal protein 4 (HE4) has great significance as a biomarker of concern for reflecting ovarian cancer. Herein, we prepared a novel optical label that can be used in lateral-flow immuno-dipstick assay (LFIA) for sensitive visual detection of HE4 by implanting hydrophobic gold nanoparticles (Au NPs) at high density in Mg/Fe LDH nanoflowers (MF NFs). MF NFs with large specific surface area, high porosity, abundant active binding sites, and stable structure were employed for the first time as templates to directly anchor Au NPs in the organic phase. After simple modification with an optimized amount of branched polyethyleneimine, not only could MF@Au NFs be dispersed in the aqueous phase, but also amino functional groups were introduced on its surface to facilitate subsequent antibody coupling steps. The limit of detection reaches 50 pM with a detection range of 50 to 1000 pM. This work initially explored how MF NFs can be used to load signal labels with ideal stability and signal amplification capabilities, which greatly improves the practicability of LFIA and highlights its important role in the field of rapid diagnostics.

One-pot alkaline carbonization hydrothermal synthesis of halloysite nanotubes with amino groups over Pd@CeO2/halloysite to enhance catalysis of three-way reactions

The three-way catalytic activity of the halloysite (Hal)-supported Pd@CeO2 (P@C) catalyst was enhanced by hydrothermal carbonization. The P@C/4–1.0C-175H catalyst (P@C was loaded with carbonized Hal with a mass ratio of cellulose/Hal = 1, the temperature was 175 °C, and t = 4 h) showed higher catalytic efficiency than P@C/H (without modification) under optimal hydrothermal carbonization conditions, which was attributed to the large proportions of carbon and oxygen-containing functional groups on carbonized Hal. The T90 (full-conversion temperature) for CO conversion was decreased from 233 °C to 210 °C. On the other hand, the efficient one-pot alkaline carbonization hydrothermal synthesis combined hydrothermal carbonization and alkaline modification without complicated steps or additional active agents. The synthesis was modified, and the cellulose carbon source was substituted by lysine to induce a negative charge on the surface of Hal. The results indicated that P@C/4–1.0NC-175H exhibited strong metal-support interactions, abundant amino and oxygen-containing functional groups, and more oxygen vacancies and CeIII species. The T90 for CO conversion with P@C/4–1.0NC-175H was significantly decreased from 461 °C (P@C) to 174 °C. This research provides a simple method for enhancing metal-support interactions and improving catalytic performance.

Antioxidative and Photo-Induced Effects of Different Types of N-Doped Graphene Quantum Dots.

Due to the increasing number of bacterial infections and the development of resistivity toward antibiotics, new materials and approaches for treatments must be urgently developed. The production of new materials should be ecologically friendly considering overall pollution with chemicals and economically acceptable and accessible to the wide population. Thus, the possibility of using biocompatible graphene quantum dots (GQDs) as an agent in photodynamic therapy was studied. First, dots were obtained using electrochemical cutting of graphite. In only one synthetic step using gamma irradiation, GQDs were doped with N atoms without any reagent. Obtained dots showed blue photoluminescence, with a diameter of 19–89 nm and optical band gap of 3.23–4.73 eV, featuring oxygen-containing, amino, and amide functional groups. Dots showed antioxidative activity; they quenched •OH at a concentration of 10 μg·mL−1, scavenged DPPH• radicals even at 5 μg·mL−1, and caused discoloration of KMnO4 at 30 μg·mL−1. Under light irradiation, dots were able to produce singlet oxygen, which remained stable for 10 min. Photoinduced effects by GQDs were studied on several bacterial strains (Listeria monocytogenes, Bacillus cereus, clinical strains of Streptococcus mutans, S. pyogenes, and S. sangunis, Pseudomonas aeruginosa, and one yeast strain Candida albicans) but antibacterial effects were not noticed.

Effect of Amino, Chloro, and Methyl Functional Groups on 4-(4-Hydroxyphenyl) Piperazine by Density Functional Theory and Molecular Docking Studies

By using density functional theory (DFT), the FT-Raman, FT-IR, and UV–visible spectra of 1-amino-4-(4-hydroxyphenyl) piperazine (1AM4HPP), 1-chloro-4-(4-hydroxyphenyl) piperazine (1CL4HPP), and 1-methyl-4-(4-hydroxyphenyl) piperazine (1ME4HPP) are carried out. The comparative donor and acceptor interactions are studied for all title compounds using the NBO method. The charge transfer, chemical parameters, and biological activities are examined by highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy results. By density functional theory NLO properties of 1AM4HPP, 1CL4HPP, and 1ME4HPP are studied. The qualitative information of the molecules is carried out using molecular electrostatic potential (MEP) studies. The thermodynamic properties like entropy (S), enthalpy (H), and heat capacity (Cp) are estimated at various temperatures. For each compound, molecular docking is carried out with suitable proteins.

Simultaneously photocatalytic removal of Cr(VI) and metronidazole by asynchronous cross-linked modified sodium alginate

Conventional photocatalysts for environmental applications are mainly transitional metal compounds or precious metal nanoparticles, which suffer from weak pollutant adsorption performance, thus limited their applications for high concentrated wastewaters. In this study, asynchronous cross-linked triethylenetetramine modified sodium alginate (CFTS) was used as photocatalyst for the simultaneously catalytic degradation of Cr(VI) and metronidazole (MNZ). Experimental results suggested that asynchronous cross-linking and triethylenetetramine modification have dramatically enhanced the chemical stability as well as the adsorption and photocatalytic behavior of the material. The grafted amino functional groups and cross-linked Fe3+ ions can promote the rapid separation and transfer of electrons, thus reducing the recombination rate of photo-generated electron-hole pairs. The optimum removal rate of Cr(VI) has reached 99.5 % and MNZ can be completely removed within 20 and 30 min at pH 1.0 under UV light irradiation, respectively. The removal mechanism of Cr(VI) by CFTS is the synergistic effect of electrostatic adsorption and photocatalytic reduction, while photocatalytic oxidation dominated the degradation process of MNZ. Moreover, the removal efficiency can be enhanced in the binary solution of these two pollutants due to the utilization of photo generated electron-hole pairs, which provides new pathways in the treatment of complicated pharmaceutical and domestic sewage wastewaters.