13C Nuclear Magnetic Resonance Spectroscopy Research Articles

Design, Synthesis, and Biological Activity of Novel Triketone-Containing Phenoxy Nicotinyl Inhibitors of HPPD.

4-Hydroxyphenylpyruvate dioxygenase (HPPD) is a crucial target enzyme in albino herbicides. The inhibition of HPPD activity interferes with the synthesis of carotenoids, blocking photosynthesis and resulting in bleaching and necrosis. To develop herbicides with excellent activity, a series of 3-hydroxy-2-(6-substituted phenoxynicotinoyl)-2-cyclohexen-1-one derivatives were designed via active substructure combination. The title compounds were characterized via infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopies, and high-resolution mass spectrometry. The structure of compound III-17 was confirmed via single-crystal X-ray diffraction. Preliminary tests demonstrated that some compounds had good herbicidal activity. Crop safety tests revealed that compound III-29 was safer than the commercial herbicide mesotrione in wheat and peanuts. Moreover, the compound exhibited the highest inhibitory activity against Arabidopsis thaliana HPPD (AtHPPD), with a half-maximal inhibitory concentration of 0.19 μM, demonstrating superior activity compared with mesotrione (0.28 μM) in vitro. A three-dimensional quantitative structure-activity relationship study revealed that the introduction of smaller groups to the 5-position of cyclohexanedione and negative charges to the 3-position of the benzene ring enhanced the herbicidal activity. A molecular structure comparison demonstrated that compound III-29 was beneficial to plant absorption and conduction. Molecular docking and molecular dynamics simulations further verified the stability of the complex formed by compound III-29 and AtHPPD. Thus, this study may provide insights into the development of green and efficient herbicides.

Molecular simulation of the regulation mechanism of surfactant on microscopic chemical wetting of coal

To explore the influence mechanism of surfactants on the wettability of coal, elemental analysis, Fourier-transform infrared spectroscopy, 13C nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy were applied to characterize the chemical structure of coal before and after modification with solutions having different concentrations of sodium dodecyl sulfate. Macromolecular models of four different coal samples before and after modification were constructed, and the mechanism of the change in the chemical structure of the coal before and after modification on its wettability was then studied with molecular dynamics (MD) simulations. The molecular formulas of the four coal samples were determined to be C160H114O34N2S, C203H144O44N3S, C196H137O42N3S, and C242H171O56N3S. Aromatic carbon accounts for a relatively high proportion of these formulas, mainly in the form of benzene rings and naphthalene. The ratios of aromatic bridge carbons to pericarbons are 0.3, 0.23, 0.21, and 0.22, respectively. Nitrogen (N) and sulfur (S) are present as pyrrole nitrogen and thiol thiophenol, respectively. MD simulations show that compared with the original coal sample, the thickness of the absorption layer between the modified coal and water molecules increases, and the interaction energy is enhanced. The maximum electrostatic potential of the surface of coal molecules in the four systems (−0.07826, −0.07915, −0.08511, and −0.10711 a.u.) is concentrated around the oxygenated functional groups. After the modification, the distribution of oxygenated functional groups is more extensive, and the content of water molecules adsorbed on the surface of the coal increases because of static electricity, which promotes the wettability of the coal. This research reveals the microscopic wetting mechanism of coal dust at the molecular level and provides a research path that offers important guidance for the reduction of coal dust that is generated during mining.

Heteroatom decorated polythiourethane sorbent for copper (II) extraction in wastewater treatment

AbstractCopper ions in wastewater present substantial environmental hazards, toxic to aquatic species and prone to bioaccumulation. Addressing this, we present a novel cross‐linked polythiourethane (C‐PTU) as a promising chelating adsorbent for the effective removal of copper ions from wastewater. A new monomer, 5‐(2,2,2‐trifluoroacetamide) benzene‐1,3‐bis(carbonyl) isothiocyanate (TFA‐ITC), was synthesized and further condensed with a 1,4‐butane diol to produce a trifluoroacetamide functionalized polythiourethane (TFA‐PTU) and subsequently generating amine functionalized polythiourethane (A‐PTU). The cross‐linking reaction was carried out through amino groups present on the polymer backbone with terephthaloyl chloride, resulting in the formation of C‐PTU. The monomer and polymers underwent characterization using Fourier transform infrared, 1H, and 13C nuclear magnetic resonance spectroscopy, with X‐ray diffraction analyzing the resin's chain alignment. Thermogravimetric and differential scanning calorimetry assessed C‐PTU's thermal properties. The adsorption process for Cu(II) ions was studied using atomic absorption spectroscopy, optimizing conditions for maximal uptake. Results revealed that C‐PTU exhibited a significant adsorption capacity for Cu(II) ions, reaching 67% after a 2 h contact time, with optimal adsorption occurring at pH 6. The Langmuir adsorption isotherm described the sorption mechanism, indicating favorable monolayer cation adsorption via coordination with donor sites on C‐PTU. This research presents a viable solution for copper ion contamination in wastewater, illustrating C‐PTU as an efficient, environmentally friendly adsorbent, marking progress toward cleaner water resources.

Isolation and Structure Analysis of Chitin Obtained from Different Developmental Stages of the Mulberry Silkworm (Bombyx mori).

Chitin, a ubiquitous biopolymer, holds paramount scientific and economic significance. Historically, it has been primarily isolated from marine crustaceans. However, the surge in demand for chitin and the burgeoning interest in biopolymers have necessitated the exploration of alternative sources. Among these methods, the mulberry silkworm (Bombyx mori) has emerged as a particularly intriguing prospect. To isolate chitin from Bombyx mori, a chemical extraction methodology was employed. This process involved a series of meticulously orchestrated steps, including Folch extraction, demineralization, deproteinization, and decolorization. The resultant chitin was subjected to comprehensive analysis utilizing techniques such as attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), 13C nuclear magnetic resonance (NMR) spectroscopy, and wide-angle X-ray scattering (WAXS). The obtained results allow us to conclude that the Bombyx mori represents an attractive alternative source of α-chitin.

Selective acylation of chitosan oligomers by several cyclic anhydrides as a 13C NMR quantification method

The chemistry of chitosan is a promising way to afford biobased and biodegradable complex materials using highly reactive compounds such as anhydrides. However, the potential applications are limited due to the absence of control over the acylation and the lack of precise characterization. After a model study on glucosamine, a selective acylation method of amines or alcohols of chitosan oligomers using anhydrides has been developed. The N-acylation of chitooligosaccharides has been achieved using several anhydrides and the O-acylation has been achieved in three steps: (1) Amine protection using p-anisaldehyde (2) O-acylation (with four anhydrides), and (3) Amine deprotection by removing the protective anisyl groups. Functionalized chitooligosaccharides have been characterized by a precise quantification method using 13C nuclear magnetic resonance spectroscopy. The resulting degrees of substitution show in most of the cases a stochiometric reaction between anhydrides and amines of chitooligosaccharides, and around 70 % of efficiency for O-acylation, proving the promising potential of such modifications. To the best of our knowledge, we describe here the first example of selective acylation of chitooligosaccharides using anhydrides, and most of all the first example of 13C quantitative NMR spectroscopy performed on chitooligosaccharides and its derivatives. These innovative structures are the gateway to the creation of new biosourced and/or biodegradable surfactants.

Construction of a food waste biochar model and determination of contaminant adsorption sites: Combining experimental characterisation with quantum chemical calculations

Increasing urbanization has made it a serious challenge to deal with food waste (FW) from people and wastewater with pollutants from industry. Biochar from FW pyrolysis(FWB) can be used as an adsorbent to adsorb pollutants from wastewater, but its molecular structure is still unknown, limiting the understanding of its adsorption mechanism and its application in industry. In this paper, a series of combined methods of experimental characterization and quantum chemical calculations, such as solid-state 13C nuclear magnetic resonance spectroscopy (13C NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to investigate and successfully construct a model of the molecular structural features of FWB under the optimal contaminant adsorption preparation conditions. Based on the electrostatic potential distribution and adsorption experiments, the adsorption sites of the pollutants were elucidated. The results showed that the FWB prepared at different temperatures, 450 °C had a variety of oxygen-containing functional groups and polarity favorable for adsorption. In the molecular structure of FWB with the molecular formula C60H49N7O8, oxygen is present in the form of carboxyl, carbonyl, ether, alcohol hydroxyl, and phenol hydroxyl groups with numbers 1, 1, 1, 1, 2, 1, 2. Nitrogen is present in the form of pyridinyl nitrogen, pyrrolidinyl nitrogen, and primary amines with numbers 1, 1, and 5, respectively. In addition, nitrogen-containing and oxygen-containing functional groups are possible adsorption sites for pollutants on FWB, and alcohol hydroxyl and amino groups can bind better to Cu2+, which provides scientific guidance for improving the adsorption performance of biochar. This provides a solid foundation for the study of the microscopic adsorption mechanism of FWB and a method for the modeling of biochar from other biomasses.

Development of a facile one-pot synthesized fluorescent green polyesters as cooling water antiscalants for industrial application

Currently, antiscalants used in cooling water are expected to be environmental-friendly, good scale inhibitive, fluorescence tracing, and industrial-friendly. Aliphatic biodegradable photoluminescent polymers (BPLPs) synthesized from citric acid, aliphatic diols, and various amino acids are fluorescent polymers containing heteroatom six-membered conjugated ring chromophores. Their cross-linked BPLPs have potential for use as implant or device materials, and vivo bioimaging probes. However, so far, no one has found that BPLPs can be used as efficient antiscalants for cooling water. In this work, we demonstrate a facile one-pot microwave-assisted synthesis of BPLPs from cost-effective materials. The products were characterized by Fourier transforms infrared spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy, gel permeation chromatography, and fluorescence spectroscopy. Thus prepared BPLPs can be directly used as a novel type green fluorescent antiscalant without further purification. They have an excellent calcium phosphate inhibition efficiency that can reach 98.6 % with a dosage of 25 mg·L−1 in the static scale inhibition test at 80 °C.

Isolation, characterization and anti-inflammatory activity of compounds from the Vernonia amygdalina

The need to explore the abundance of natural products cannot be overemphasized particularly in the management of various disease conditions. In traditional medical practice, Vernonia amygdalina has been widely adopted in the management of various inflammatory disorders. The objective of this investigation was to isolate the bioactive principles from the stem-bark and root of V. amygdalina and assess the anti-inflammatory (in vitro) activity of both the crude extracts and the isolated compounds. Following extraction with the methanol, the extract was subjected to gravity column chromatography and the resultant fractions was further purified to obtained pure compounds. The structural elucidation of the compounds were based on data obtained from 1H to 13C nuclear magnetic resonance (NMR) spectroscopies as well as fourier transform infrared (FT-IR). Using diclofenac as a control drug, the albumin denaturation assay was used to determine the in vitro anti-inflammatory activity of the extracts and isolates. Three distinct compounds characterized are vernoamyoside D, luteolin-7-α-o-glucuronide, and vernotolaside, a new glycoside. When compared to diclofenac, which has an IC50 of 167.8 μg/mL, luteolin-7-α-o-glucuronide, vernoamyoside D, and vernotolaside all showed significant inhibitions with respective IC50 values 549.8, 379.5, and 201.7 μg/mL. Vernotolaside is reported for the first time from the root. The assertion that the plant is used in traditional medicine for the management of inflammatory disorder is somewhat validated by the confirmation of the existence of the compounds with the biochemical actions. Further validation of the isolated compounds would be required in animal studies.

The immobilization of cadmium by rape straw derived biochar in alkaline conditions: Sorption isotherm, molecular binding mechanism, and in-situ remediation of Cd-contaminated soil

The issue of cadmium (Cd) contamination in alkaline soils is escalating, necessitating the prompt implementation of effective passivation strategies. Biochar has gained significant attention for its potential in immobilizing heavy metals; however, the suitability of biochar as a remediation material and its micro-scale interaction mechanisms with Cd under alkaline conditions remain unclear. Rape straw (RS) were pyrolyzed at 400°C (RB400) and 700°C (RB700) to produce biochar. Adsorption and soil incubation experiments were carried out to assess the feasibility of using rape straw derived biochar pyrolyze at different temperatures and understanding their remediation mechanisms in alkaline environments. The sorption capacity for Cd immobilization was evaluated using sorption isotherms, revealing that RB700 exhibited enhanced Cd sorption performance with a maximum sorption capacity of 119.33 mg g-1 calculated from the Langmuir isotherm equation at pH 8. Cd L3-edge X-ray sorption near-edge structure (XANES) spectroscopy analysis confirmed that the dominant sorption species of Cd were organic Cd in RB400, with CdCO3 precipitation increased to 73.9% in RB700. Solid-state 13C nuclear magnetic resonance (13C-NMR) spectroscopy demonstrated that aromatic and carboxyl C functional groups are involved in the organic sorption of Cd through complexation and Cd2+-π interactions in alkaline solutions. The precipitation of CdCO3 in RB700 may resulted in a more effective passivation effect compared to RB400, leading to a significant 15.54% reduction in the DTPA-Cd content in Cd-contaminated soil. These findings highlight the effective Cd passivation Cd in alkaline environments by rape straw derived biochar, providing new molecular insights into the Cd retention mechanism of biochar. Furthermore, it presents novel ideas for improving remediation approaches for alkaline Cd-contaminated soils.

Improving probiotic survival through encapsulation in coconut oil in whey protein isolate emulsions during spray drying and gastrointestinal digestion

Enhancing probiotic survival during spray drying and gastrointestinal transit is crucial for efficient probiotic production. In this study, whey protein isolate (WPI) alone and coconut oil (CO) in WPI emulsions at varying concentrations of CO, specifically 4% and 8% (referred to as 4CO-WPI and 8CO-WPI, respectively), were employed as encapsulants for spray drying Limosilactobacillus reuteri KUB-AC5. The proteins in the emulsions exhibited a higher degree of unfolding and surface hydrophobicity compared to WPI alone, leading to reduced contact angles with hydrophobic cells. Analysis through 13C-Nuclear Magnetic Resonance spectroscopy revealed increased interactive sites of the unfolded proteins in 4CO-WPI and 8CO-WPI with peptidoglycan and protein-bound surfaces. Cells encapsulated in 4CO-WPI exhibited superior survival and minimal cell envelope injury. These encapsulated cells displayed the highest viability during simulated gastrointestinal digestion, with a final count of 8.76 log CFU/g. Both 4CO-WPI and 8CO-WPI experienced lower hydrolysis compared to WPI, indicating enhanced cell survival. These findings emphasize the importance of enhancing the interaction between the unfolded proteins in the emulsions, obtained through complexation with CO, and the cell wall. This enhancement results in increased cell survival throughout the entire process, emphasizing the potential for improved probiotic production methods.

Analysis of natural organic matter chemistry in bentonite clay under compaction using different dry densities and duration

The Nuclear Waste Management Organization of Canada has adopted an adaptive phased management plan for the long-term storage of used nuclear fuel in a Deep Geological Repository (DGR). The DGR barrier system employs copper-coated used fuel containers (UFCs) surrounded by buffer material which is composed of highly compacted bentonite clay. The natural organic matter (NOM) composition of the compacted bentonite is of practical importance for the safety assessment as it regulates the biogeochemical processes at the interface between the UFCs and the buffer layer. However, insufficient investigations on NOM constituents limits the understanding of biogeochemical dynamics in bentonites compacted under different dry densities. This study analyzed the carbon content and NOM composition using targeted compound analysis and solid-state 13C nuclear magnetic resonance (NMR) spectroscopy with bentonites compacted at 1.1, 1.4 or 1.6 g/cm3 dry density for 1, 3, 6, 12 or 18 months. Organic carbon contents were similar across bentonites with different compaction densities at various durations as compared to the reference clay (powdered bentonite sample before compaction). The overall NOM composition measured by solid-state 13C NMR suggested a predominance of alkyl and aromatic carbon in bentonite samples. No marked variations were observed for the NOM components (i.e., alkyl, O-alkyl and aromatic carbon) between the compacted bentonites and the reference clay. Targeted compound analysis revealed that the extractable lipid concentrations in the compacted clays did not significantly vary from the reference bentonite with only some compounds exhibiting nano-gram level differences. Bentonites with relatively lower dry densities (1.1 and 1.4 g/cm3) demonstrated slightly higher extractable compound concentrations, but these differences were not statistically significant. In contrast, the compound concentrations of bentonites compacted to 1.6 g/cm3 were similar or slightly lower compared with the reference bentonite, likely associated with limited microbial growth under high dry compaction density. Taken together, these results suggested that NOM composition and quantity did not significantly alter in bentonites under various pressures nor with longer experimental durations. These findings highlight that compacted bentonite exhibited geochemical stability under the simulated repository environments, which provides critical insight for design and performance of engineered barrier system in a DGR concept.

A Cu2+ fluorescent chemosensor suitable for quantitative detection of tyrosinase in potatoes over a wide pH range.

Cu2+ as an important trace element plays an essential role in various biologic processes due to the unique redox active nature. For this reason, much effort has been made to develop effective methods for Cu2+ detection. In this study, a novel structure fluorescent chemosensor, 1-(6-(((5-(5, 5-difluoro-1, 3, 7, 9-tetramethyl-5H-4λ4, 5λ4-dipyrrolo[1, 2-c:2', 1'-f][1, 3, 2] diazaborinin-10-yl)quinolin-8-yl)oxy)methyl)pyridin-2-yl)-N, N-bis(pyridin-2-ylmethyl)methanamine (1), was synthesized and characterized by 1H and 13C nuclear magnetic resonance spectroscopy, and electrospray ionization mass spectrometry. Sensor 1 showed an obviously "on-off" fluorescence response to Cu2+ with a 1:1 binding stoichiometry by UV-vis and fluorescence spectrophotometry. The detection limit of sensor 1 to Cu2+ was determined to be 1.9µM, and the stable pH range for Cu2+ detection was from 3 to 13. Sensor 1 can be used for recognition and detection of tyrosinase in potatoes.

From Pulp to Aromatic Products-Reaction Pathways of Lignin Depolymerization.

This study investigated the depolymerization of lignin into aromatic monomer compounds under hydrothermal conditions. A reaction scheme highlighting secondary alkylation reactions as well as the molecular weight shift was developed based on the experimental data. Lignin is produced in large quantities in paper production and dissolved in what is known as black liquor (BL). To avoid lignin recovery as an additional process step, BL is used directly as feedstock in the hydrothermal liquefaction (HTL) in this work. We performed various batch experiments in micro autoclaves with BL and model substances at different reaction temperatures (TR = 250-400 °C) and a holdingtime of tR = 20 min, as well as continuous experiments (TR = 325-375 °C, tR = 20 min). We were able to show that different derivatives of catechols are the main products among the monomers in our process. With the help of the model substance experiments, we were able to work out three main reactions: demethoxylation, demethylation, and alkylation. This behavior could be observed in the case of BL from hardwood as well as from softwood. 31P nuclear magnetic resonance (NMR) spectroscopy analysis has shown that these reactions take place on aromatic monomers as well as on larger aromatic oligomer structures. At higher temperatures, a large fraction of the carbon ends up in the solid product, while the yields of the monomers decrease sharply. 13C NMR spectroscopy of the solid material shows that the monomers are probably incorporated into the solid phase by repolymerization. We were also able to see this effect using size exclusion chromatography analysis based on the relative molecular weight. From all of the analytical results of the products, a reaction scheme was developed that describes the reaction pathways of the lignin during HTL. Based on this, a reaction kinetic model can be developed in the next step.

Bis(2,2,6,6-tetramethyl-1-(λ1-oxidaneyl)piperidin-4-yl) 3,3′-((2-hydroxyethyl)azanediyl)dipropionate

TEMPO-containing conductive polymers are used in organic electronics due to their electrochemical properties. One of significant limitations in developing such materials is the structural modification by several TEMPO moieties. Here, we report a synthesis of the first-generation dendrimer containing two TEMPO fragments, bis(2,2,6,6-tetramethyl-1-(λ1-oxidaneyl)piperidin-4-yl) 3,3′-((2-hydroxyethyl)azanediyl)dipropionate, that can be implemented into a conductive polymer structure. The resulting product was characterized using 1H and 13C nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectroscopy (HRMS).

Synthesis of copolymers based on divinylbenzene and dibenzocyclobutyldimethylsilane and a study of their functional characteristics

Objectives. To create new polymer materials based on organosilicon derivatives of benzocyclobutene and to study the possibility of their use as insulating dielectric layers in micro- and microwave electronics devices.Methods. The synthesis of the dibenzocyclobutyldimethylsilane (diBCB-DMS) monomer was carried out from 4-brombenzocyclobutene through the production stage of the Grignard reagent. Copolymers based on divinylbenzene and dibenzocyclobutyldimethylsilane were obtained by means of thermal polymerization. The properties and structure of the copolymers thus obtained were studied using the following methods: thermogravimetric analysis, infrared spectroscopy, nuclear magnetic resonance (NMR), mass spectroscopy, and by means of high-frequency measurements of volt-ampere characteristics and volumetric resonator.Results. diBCB-DMS was synthesized with a yield of 81.5%. The composition and structure were confirmed by 1H and 13C NMR spectroscopy. The dielectric constant of the diBCB-DMS homopolymer is ~2.6. The tangent of the dielectric loss angle at 1 GHz of the diBCB-DMS homopolymer is 2.3∙10−4. The tangent of the dielectric loss angle at 10 GHz of the diBCB-DMS homopolymer is 2.6∙10−4. The study of divinylbenzene and diBCB-DMS copolymers in different molar ratios on a thermogravimetric analyzer showed that the copolymers are able to withstand temperatures up to 470°C. The dielectric permittivity of diBCB-DMS and divinylbenzene copolymers in a molar ratio of 1 : 1 was 2.6. The values of the loss tangent at 1 and 10 GHz of copolymers in a molar ratio of 1 : 1 were 4.0∙10−4 and 5.6∙10−4, respectively.Conclusion. Analysis of the obtained results shows that the samples of the diBCB-DMS homopolymer have the same dielectric characteristics as the samples based on diBCB-DMS and divinylbenzene, therefore, the introduction of divinylbenzene into the polymer structure does not worsen the dielectric parameters and such polimer materials can be used at high temperatures.

Phytochemical Screening of <i>Diospyros paniculata</i> Bark and <i>In Vitro</i> Cytotoxic Study on Human Breast Cancer Cell Line

Medicinal plants are the resource of traditional medicines and modern medicine is also developed indirectly from plants. In traditional medicinal practices such as Ayurveda and Unani, Diospyros paniculata has been recognised for its medicinal properties. Different parts of the plant, including the leaves, bark, fruits, and seeds, are utilised to prepare various herbal remedies and these species show a richness of triterpenoids, naphthoquinones and naphthaldehydes which majorly contribute to the anticancer activity. D. paniculata bark was extracted with methanol and fractionated by low-polar to high-polar solvents. In-vitro cytotoxic activity of each solvent fraction was studied on the MCF-7 (Human Adenocarcinoma) cell line by MTT assay. The ethyl acetate fraction shows a significant IC50 value of 23.47 µg/ml which might be due to the presence of principal compounds in the fraction. Methanol fraction showed a moderate IC50 value. To isolate chemicals, the chloroform fraction underwent column chromatography. Fourier Transform Infrared Spectroscopy (FTIR), 1H NMR (Nuclear Magnetic Resonance Spectroscopy), and 13C NMR were used to characterise the isolated chemicals. Two compounds were isolated from chloroform fraction identified as Betulin and Lupeol.

Synthesis, Spectroscopic Evaluations and UV-Vis Titration Studies of New Symmetrical Amide Compounds Derived from N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic Acid Methyl Ester

          In this study, 2 flexible and pre-organized tetraamide compounds derived from N-6-[(4-pyridylmethylamino)carbonyl]-pyridine-2-carboxylic acid methyl ester namely 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]pentane (L1) and 1,2-bis[N,N’-6-(4-pyridylmethylamido)pyridyl-2-carboxyamido]hexane (L2) have been successfully synthesized when reacted with diamines in 1:2 ratio. These new compounds were built from combination of 3 main components, as a trend requires for anion receptor which are (i) 2,6-pyridine dicarboxamide moieties as targeted anion binding host, (ii) amino methyl pyridine pendants arms as the flexible moieties and (iii) pentyl (-C5H10-) and hexyl (-C6H12-) unit as the spacer. Compounds L1-L2 were fully characterized by using elemental analyzer, Fourier transform infrared (FTIR) spectroscopy, gas chromatography-mass spectroscopy (GC-MS), 1H, 2D NOESY and 13C Nuclear Magnetic Resonance (NMR) spectroscopies, and Ultraviolet-visible (UV-Vis) spectroscopies. In this study, anion titration methods were used to identify the affinity towards selected anions. The results showed that L1 (having a pentyl spacer) had the highest affinity towards phosphate anions as compared to L2, where the red shift changes were observed in the UV-vis spectrum at the amide region. HIGHLIGHTS Two novel amide compounds with flexible and pre-organized structure are designed for use as potential anion receptors The flexible moieties at the amide and the linker allow hydrogen bonding interaction of the molecules with variety anions with different geometries Anion titration studies revealed good affinities towards phosphate anions as suggested in Hofmeister trend GRAPHICAL ABSTRACT

Structural Characterization and Molecular Model Construction of Lignite: A Case of Xianfeng Coal

The object of the study is lignite. Analytical testing techniques, such as elemental analysis, 13C nuclear magnetic resonance (13C NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), were used to acquire information on the structural parameters of lignite. The aromaticity of Xianfeng lignite is 43.57%, and the aromatic carbon structure is mainly naphthalene and anthracene/phenanthrene. The aliphatic carbon structure is dominated by cycloalkanes, alkyl side chains, and hydrogenated aromatics. Oxygen is mainly present in ether oxygen, carboxyl, and carbonyl groups. Nitrogen is mainly in the form of pyrrole nitrogen and quaternary nitrogen. Sulfur is mainly thiophene sulfur. According to the analysis results, the molecular structure model of XF lignite was constructed. The molecular formula is C184H172O39N6S2. The 2D structure was converted to a 3D structure using computer simulation software and optimized. The optimized model has a remarkable stereoconfiguration, and the aromatic lamellae are irregularly arranged in space. The aromatic rings were mainly connected by methylene, hypomethylene, methoxy, and aliphatic rings. In addition, the simulated 13C NMR spectra are in good agreement with the experimental spectra. This shows the rationality of the 3D chemical structure model.

Metal-organic framework MIL-101(Cr): An efficient catalyst for the synthesis of dihydro-pyrimidinones

In this work, a metal–organic framework, MIL-101(Cr), was synthesized using hydrothermal method. As synthesized MIL-101(Cr) was characterized using various techniques such as X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDAX), Raman spectroscopy, and Brunauer-Emmett-Telller (BET) surface area analysis. Dihydro-pyrimidinone derivatives were synthesized in the absence of solvent over the MIL-101(Cr) catalyst. These dihydro-pyrimidinone derivatives were characterized by FTIR, 1H and 13C nuclear magnetic resonance spectroscopy. Less hazardous reactants, milder reaction conditions, and relatively simple catalysts to synthesize dihydro-pyrimidinones are the added advantages of our protocol. Optimal yield, swift reaction time, and the retention of a good catalytic activity up to five cycles are the special benefits of our protocol.

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity.

Herein, a series of chitosan oligosaccharide copper complexes modified with pyridine groups (CPSx-Cu complexes) were successfully prepared via the Schiff base reaction and ion complexation reaction for slow-release fungicide. The structures of the synthesized derivatives were characterized via Fourier transform infrared spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy, and the unit configuration of the complexes was calculated using Gaussian software. The slow-release performance experiment demonstrated that the cumulative copper ion release rate of CPSx-Cu complexes was dependent on the type of substituents on the pyridine ring. Furthermore, the in vitro and in vivo antifungal activities of the CPSx-Cu complexes were investigated. At a concentration of 0.4 mg/mL, CPSx-Cu complexes completely inhibited the growth of Pythium vexans and Phytophthora capsici. Results indicated that CPSx-Cu complexes with slow-release ability exhibited better antifungal activity than thiodiazole-copper and copper sulfate basic. This study confirmed that combining chitosan oligosaccharide with bioactive pyridine groups and copper ions is an effective approach to further developing slow-release copper fungicides, providing new possibilities for the application of copper fungicides in green agriculture. This study lays the foundation for further studies on biogreen copper fungicides.