Crude Mixture Research Articles

Deconvolution and Analysis of the 1H NMR Spectra of Crude Reaction Mixtures.

Nuclear magnetic resonance (NMR) spectroscopy is an important analytical technique in synthetic organic chemistry, but its integration into high-throughput experimentation workflows has been limited by the necessity of manually analyzing the NMR spectra of new chemical entities. Current efforts to automate the analysis of NMR spectra rely on comparisons to databases of reported spectra for known compounds and, therefore, are incompatible with the exploration of new chemical space. By reframing the NMR spectrum of a reaction mixture as a joint probability distribution, we have used Hamiltonian Monte Carlo Markov Chain and density functional theory to fit the predicted NMR spectra to those of crude reaction mixtures. This approach enables the deconvolution and analysis of the spectra of mixtures of compounds without relying on reported spectra. The utility of our approach to analyze crude reaction mixtures is demonstrated with the experimental spectra of reactions that generate a mixture of isomers, such as Wittig olefination and C-H functionalization reactions. The correct identification of compounds in a reaction mixture and their relative concentrations is achieved with a mean absolute error as low as 1%.

Size-Selective Capturing of Exosomes Using DNA Tripods.

Fractionating and characterizing target samples are fundamental to the analysis of biomolecules. Extracellular vesicles (EVs), containing information regarding the cellular birthplace, are promising targets for biology and medicine. However, the requirement for multiple-step purification in conventional methods hinders analysis of small samples. Here, we apply a DNA origami tripod with a defined aperture of binders (e.g., antibodies against EV biomarkers), which allows us to capture the target molecule. Using exosomes as a model, we show that our tripod nanodevice can capture a specific size range of EVs with cognate biomarkers from a broad distribution of crude EV mixtures. We further demonstrate that the size of captured EVs can be controlled by changing the aperture of the tripods. This simultaneous selection with the size and biomarker approach should simplify the EV purification process and contribute to the precise analysis of target biomolecules from small samples.

Synthesis and Energetic Characterization of Borane-Amines on High-Nitrogen Heterocycles.

Borane-amines have garnered attention over the last several decades in a variety of applications, ranging from hydrogen storage materials to hypergolic fuel systems. An investigation into the synthesis of borane-amines with high-nitrogen content heterocycles was undertaken in this work. Borane-amines were formed by the reaction of BH3·Me2S in tetrahydrofuran (THF) with the requisite nitrogen-containing heterocycle and isolated by placing the crude reaction mixture in hexanes to precipitate the product. X-ray crystallography, thermogravimetric analysis (TGA), high resolution mass spectroscopy (HRMS), 1H NMR, 13C NMR, and 11B NMR were utilized for product characterization, while impact and friction sensitivity testing were conducted to identify sensitivity in the synthesized compounds. Most isolated borane-amines, except one, were found to decompose in the atmosphere and were more sensitive to mechanical stimuli than their starting materials; however, all synthesized compounds were found to be hypergolic in the presence of white fuming nitric acid (WFNA).

Exploring the biological diversity and source species of medicinal horseflies through metabarcoding

Horseflies from the Tabanidae family play a significant role in traditional Chinese medicine to treat various health conditions, including coronary heart disease, stroke, headaches, liver cirrhosis, psoriasis, and hepatic carcinoma. There are 27 species of Tabaninae (Tabanidae) used as medicine, and they showed high morphological similarities with those for which medicinal properties have not been reported. Nonetheless, there have been reports suggesting that medicinal crude drugs sometimes contain irrelevant or false species, impacting the drug's efficacy. In this current study, we collected 14 batches, totaling 13,528 individuals, from various provinces in China. Instead of “classic” DNA barcoding strategy, we employed a high-throughput metabarcoding approach to assess the biological composition of crude drug mixtures derived from horseflies. Our analysis identified 40 Amplicon Sequence Variants (ASVs) with similarity percentages ranging from 92% to 100% with 12 previously reported species. Species delimitation methods revealed the presence of 11 Molecular Operational Taxonomic Units (MOTUs), with ten belonging to the Tabanus genus and one to Hybomitra. Tabanus sp6 displayed the highest relative abundance, and its ASVs showed close resemblance to Tabanus pleski. Our investigations revealed that the medicinal batches were biologically composed of 6 to 12 species. Some batches contained ASVs that closely resembled species previously associated with false Tabanus species. In conclusion, our findings offer valuable insights into the biological composition of crude drugs derived from horseflies and have the potential to enhance the quality of these traditional medicines.

Preliminary membrane screening and evaluation for the separation of bioethanol obtained from fermentation of oil palm empty fruit bunch (OPEFB)

This study evaluates the effectiveness of some commercial membranes (polytetrafluoroethylene [PTFE], polyvinylidene fluoride [PVDF], polyethersulfone [PES], and nitrocellulose [NC]) in concentrating a binary ethanol-water mixture under different conditions (volumes, temperatures, pressures, and concentrations). Then, the membrane was selected based on its performance for use in ethanol and by-product separation from OPEFB fermentation broth. The optimum result for the binary ethanol-water separation was found in the PVDF membrane with the highest separation factor of 3.03 and flux of 0.015 g.cm−2 s−1 under 10 ml permeate volume, 75 °C temperature, 60 psi pressure, and 20 % (v/v) ethanol concentration. Based on the membrane field emission-scanning electron microscope (FE-SEM) analysis, the PVDF membrane also had the lowest swelling degree. Utilization of the PVDF membrane to separate crude bioethanol resulting from OPEFB fermentation gave a separation factor of 3.66. The initial bioethanol concentration was 7.67 % (v/v), and the ethanol concentration in the permeate was 23.31 % (v/v). In addition, the separation factor of propanol from the crude mixture was 5.44, and the acetic acid rejection factor was 96.7 %. The S.cerevisiae suspension and the cellulase enzyme were also separated and recovered in the retentate phase. Hence, the PVDF membrane can be used to separate bioethanol from the yeast and enzyme suspension while pre-concentrating the bioethanol product. This could eventually help reduce the energy requirement to obtain industrial-grade bioethanol.

Rapid reaction optimization by robust and economical quantitative benchtop 19F NMR spectroscopy.

The instrumental analysis of reaction mixtures is usually the rate-determining step in the optimization of chemical processes. Traditionally, reactions are analyzed by gas chromatography, HPLC or quantitative NMR spectroscopy on high-field spectrometers. However, chromatographic methods require elaborate work-up and calibration protocols, and high-field NMR spectrometers are expensive to purchase and operate. This protocol describes an inexpensive and highly effective analysis method based on low-field benchtop NMR spectroscopy. Its key feature is the use of fluorine-labeled model substrates that, because of the wide chemical shift range and high sensitivity of 19F, enable separate, quantitative detection of product and by-product signals even on low-field, permanent magnet spectrometers. An external lock/shim device obviates the need for deuterated solvents, permitting the direct, noninvasive measurement of crude reaction mixtures with minimal workup. The low field-strength facilitates a homogeneous excitation over a wide chemical shift range, minimizing systematic integration errors. The addition of the optimal amount of the nonshifting relaxation agent tris(acetylacetonato) iron(III) minimizes relaxation delays at full resolution, reducing the analysis time to 32 s per sample. The correct choice of processing parameters is also crucial. A step-by-step guideline is provided, the influence of all parameters, including adjustments needed when using high-field spectrometers, is discussed and potential pitfalls are highlighted. The wide applicability of the analytical protocol for reaction optimization is illustrated by three examples: a Buchwald-Hartwig amination, a Suzuki coupling and a C-H arylation reaction.

A superhydrophilic/air superoleophobic sponge based on low-temperature vacuum evaporation deposition modification for saving marine crude oil pollution and leakage

Oil pollution and crude oil leakage in the ocean have severely impacted marine ecology. The emergence of super-wetting materials provides a new approach to addressing the issue of oil leakage. Chemical vapor deposition, which can be applied to prepare super-wetting materials, is a method that can modify uniformly and enhance the stability of the material, while mostly needing to be performed at high temperatures. In this study, melamine sponge (MS) was preliminarily modified by low-temperature vacuum evaporation deposition (LTVED) of hydrolyzed γ-mercaptopropyl triethoxy silane (KH580). The nano-silica and FS-50 were stepwise coated on the MS skeleton by a simple immersion-drying process. A superhydrophilic/air superoleophobic sponge (MS-KCSiF) as obtained with water contact angle of nearly 0° and crude oil contact angle of approximately 154° in the air, which can retain the wetting properties after immersion in different chemical solutions, ultraviolet irradiation aging, and mechanical destruction like cutting, twisting, bending, and pressing. Its efficiency for high-viscosity crude oil-seawater mixtures was maintained at over 96 % after 20 cycles. Empowered with the shape of mortise and tenon joint structure, MS-KCSiF can scoop up spilled crude oil from the sea surface. This strategy provides a new idea for the construction of super-wetting materials and oil spill collection.

Extraction of Coumarin Mixture from Tamanu Oil using Food-Grade

Indonesia’s flora and fauna are divided into four significant ecosystems: freshwater (rivers and lakes), marine, semi-terrestrial (mangrove and riparian), and terrestrial. Tamanu (Calophyllum inophyllum) is a member of the mangrove-associated plant species belonging to the mangosteen family. It is also known as Alexandrian laurel, bintangur (Malaysia), Borneo-mahogany, polanga (India), and nyamplung (Indonesia). The tamanu seed can produce oil with a 60-75% yield. It is applicable to treat various skin problems, including eczema, psoriasis, herpes, acne, haemorrhoids, and certain allergies. It is also beneficial as an antimicrobial, anticancer, anti-HIV, anti-inflammation, and anticoagulant agent. This is because tamanu oil contains bioactive compounds named coumarin. Previous works isolated coumarins with toxic solvents and using methods that are hard to scale up. Therefore, this study aims to know the best concentration of food-grade ethanol, the number of stages, and the solvent system to extract crude coumarin mixtures from tamanu oil by batchwise solvent extraction. The free fatty acid and triglyceride removal was also studied. The initial contents of free fatty acid, coumarin mixture, and triglyceride in tamanu oil were 25.87%, 11.96%, and 51.16%, respectively. Tamanu oil was extracted simultaneously with binary solvents (n-hexane and 70%/80%/90% aqueous food-grade ethanol) and a single solvent (96% food-grade ethanol). Each fraction was analysed by Thin Layer Chromatography (TLC) and High Temperature-Gas Chromatography (HT-GC). The best result was obtained using 80% aqueous food-grade ethanol, eight extraction stages, and a binary solvent system, which produced 48.64±6.57% purity and 88.68±1.38% recovery of coumarin mixture. Moreover, it was found that the method removed 64.15% of free fatty acid and 99.96% of triglyceride from the crude tamanu oil after eight stages of batchwise extraction.

Low-valent-tungsten catalysis enables hydroboration of esters and nitriles.

In the research presented herein, low-valent-tungsten-catalyzed hydroboration of esters and nitriles was investigated. Aromatic and aliphatic substrates were smoothly reduced to corresponding alcohol derivatives and N,N-diborylamines in the presence of W(CO)4(NCMe)2. Valuable derivatives were conveniently accessed by introducing a further functionalization process to crude hydroboration mixtures in one pot.

Self-Standing Metal Foam Catalysts for Cathodic Electro-Organic Synthesis.

Although electro-organic synthesis is currently receiving renewed interest because of its potential to enable sustainability in chemical processes to value-added products, challenges in process development persist: For reductive transformations performed in protic media, an inherent issue is the limited choice of metallic cathode materials that can effectively suppress the parasitic hydrogen evolution reaction (HER) while maintaining a high activity toward the targeted electro-organic reaction. Current development trends are aimed at avoiding the previously used HER-suppressing elements (Cd, Hg, and Pb) because of their toxicity. Here, this work reports the rational design of highly porous foam-type binary and ternary electrocatalysts with reduced Pb content. Optimized cathodes are tested in electro-organic reductions using an oxime to nitrile transformation as a model reaction relevant for the synthesis of fine chemicals. Their electrocatalytic performance is compared with that of the model CuSn7Pb15 bronze alloy that has recently been endorsed as the best cathode replacement for bare Pb electrodes. All developed metal foam catalysts outperform both bare Pb and the CuSn7Pb15 benchmark in terms of chemical yield and energetic efficiency. Moreover, post-electrolysis analysis of the crude electrolyte mixture and the cathode's surfaces through inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy (SEM), respectively, reveal the foam catalysts' elevated resistance to cathodic corrosion.

Enhanced Phytoremediation and Physicochemical Parameters of Crude Oil Polluted Soil Using Pseudomonas fluorescens and Bacillus substilis

There have been worry over the Niger Delta's environmental contamination. Bacteria and other microorganisms have shown to be very helpful in the breakdown of hydrocarbons generated from petroleum. The goal of this research is to use elbow bufallow grass and sedge plants for phytoremediation of soil affected by crude oil. Standard microbiological techniques were applied to the contaminated soil once it was gathered. Using a hand auger, contaminated soil samples were taken twice a month for three months from two separate locations in Rivers State at two distinct depths: 0–15 cm and 15–30 cm. The following physicochemical parameters of samples were analysed using Standard Laboratory Procedures: pH, Temperature, Nitrogen, Phosphorus, Potassium available in the polluted soil and the total hydrocarbon content (THC). Two plant species common in the Ogoni region of Rivers state, i.e. Sedge plant (Schoenoplectus), Elbow buffalo grass (Panicum subalbidum) were used for phytoremediation monitoring. A combination of treatment consisting of the application of Pseudomonas fluorescens Bacillus substilis, Panicum subalbidum and Schoenoplectus senegalensis was evaluated during 28 days of remediation. Each pot contained crude oil mixture in the soil as a sole source of carbon and energy. THB counts ranged from 2.35 to 4.15 cfu/g. The statistical analysis revealed that there was no significant difference (p>0.05) in the total heterotrophic bacteria counts between the samples. HUB counts range from 0.7 to 1.45cfu/g. The total bacterial population counts obtained from soil sample during bioremediation monitoring ranged from 17+1.41 (CS+PAN) to 40+1.412cfu/g (CS+PSE+BAC+PAN) in Day 1. Results of Day 14 range from 13+1.41 (CS+PAN) to 35.5+3.542cfu/g (CS+BAC+SCH). Results of Day 28 ranged from 8.5+0.71 (CS+PAN) to 27+1.412cfu/g (CS+PSE+BAC+PAN). The presence of microbial activity was determined by the enumeration and isolation of total heterotrophic and hydrocarbon utilizing bacteria. The results of physicochemical parameters before bioremediation is as follows: pH (5.43), Temperature (27oC), Electrical conductivity (9), Moisture content (7.80%), Total organic carbon (0.93%), Soil organic matter (1.60%), Nitrogen (56.695mg/kg), Phosphorus (0.621mg/kg), Potassium (7.125mg/kg) and Total Hydrocarbon content (700mg/kg). Results revealed amount of soil hydrocarbon removed and percentage (%) Bioremediation remediated after 28 days of monitoring to be higher in set up with CS+PSE+SCH (3454mg/kg; 85.28%) and lowest in set up with US+SCH (434mg/kg: 62%) and the amount of root hydrocarbon content removed and percentage (%) Bioremediation remediated after 28 days of monitoring to be higher in set up with CS+BAC+SCH (632Mg/kg; 15.6%) and lowest in set up with US+SCH (12.2mg/kg; 1.74%).
 Three (3) most occurring hydrocarbon utilizing bacterial isolates were isolated and identified culturally and phenotypically from the soil samples these bacteria isolates were confirmed to be Peudomonas, Priestia megaterium and Bacillus spp molecularly via sequencing of the 16SrRNA gene. The most common bacteria isolated were Bacillus spp at a dilution of 104. This research revealed and recommend that Panicum subalbidum as a suitable plant species for phytoremediation of crude oil-contaminated soil.

Qualitative analysis of aromatic compounds via 1D TOCSY techniques

The aromatic compounds, including o-xylene, m-xylene, p-xylene, and ethylbenzene, primarily originate from the catalytic reforming of crude oil, and have a wide variety of applications. However, because of similar physical and chemical properties, these compounds are difficult to be identified by gas chromatography (GC) without standard samples. With the development of modern nuclear magnetic resonance (NMR) techniques, NMR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without purification. In this study, the parameters of one-dimensional (1D) total correlation spectroscopy (TOCSY) NMR techniques, including 1D selective gradient TOCSY and 1D chemical-shift-selective filtration (CSSF) with TOCSY, were optimized to obtain comprehensive molecular structure information. The results indicate that the overlapped signals in NMR spectra of nonpolar aromatic compounds (including o-xylene, m-xylene, p-xylene and ethylbenzene), polar aromatic compounds (benzyl alcohol, benzaldehyde, benzoic acid), and aromatic compounds with additional conjugated bonds (styrene) can be resolved in 1D TOCSY. More importantly, full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D TOCSY. This approach simplifies the NMR spectra, provides structural information of entire molecules, and can be applied for the analysis of other structural isomers.

Rapid Lewis Acid Screening and Reaction Optimization Using 3D-Printed Catalyst-Impregnated Stirrer Devices in the Synthesis of Heterocycles.

We describe the development of Lewis acid (LA) catalyst-impregnated 3D-printed stirrer devices and demonstrate their ability to facilitate the rapid screening of reaction conditions to synthesize heterocycles. The stereolithography 3D-printed stirrer devices were designed to fit round-bottomed flasks and Radleys carousel tubes using our recently reported solvent-resistant resin, and using CFD modeling studies and experimental data, we demonstrated that the device design leads to rapid mixing and rapid throughput over the device surface. Using a range of LA 3D-printed stirrers, the reaction between a diamine and an aldehyde was optimized for the catalyst and solvent, and we demonstrated that use of the 3D-printed catalyst-embedded devices led to higher yields and reduced reaction times. A library of benzimidazole and benzothiazole compounds were synthesized, and the use of devices led to efficient formation of the product as well as low levels of the catalyst in the resultant crude mixture. The use of these devices makes the process of setting up multiple reactions simpler by avoiding weighing out of catalysts, and the devices, once used, can be simply removed from the reaction, making the process of compound library synthesis more facile.

Integrated Direct-to-Biology Platform for the Nanoscale Synthesis and Biological Evaluation of PROTACs.

Proteolysis targeting chimeras (PROTACs) are heterobifunctional molecules that co-opt the cell's natural proteasomal degradation mechanisms to degrade undesired proteins. A challenge associated with PROTACs is the time and resource-intensive optimization; thus, the development of high-throughput platforms for their synthesis and biological evaluation is required. In this study, we establish an ultra-high-throughput experimentation (ultraHTE) platform for PROTAC synthesis, followed by direct addition of the crude reaction mixtures to cellular degradation assays without any purification. This 'direct-to-biology' (D2B) approach was validated and then exemplified in a medicinal chemistry campaign to identify novel BRD4 PROTACs. Using the D2B platform, the synthesis of 650 PROTACs was carried out in a 1536-well plate, and subsequent biological evaluation was performed by a single scientist in less than 1 month. Due to its ability to hugely accelerate the optimization of new degraders, we anticipate our platform will transform the synthesis and testing of PROTACs.

Comprehensive thermodynamic modeling framework for the estimation of physico-chemical properties of deep eutectic solvent-heavy crude oil system

Physico-chemical properties such as density, solubility parameter, viscosity, volume change on mixing and surface tension for pure deep eutectic solvent (DES), heavy crude oil (saturate, aromatic, resin and asphaltene i.e. SARA) and DES-SARA mixtures are estimated. The models are established considering the variation of SARA from three geographic locations and five DESs from hydrophilic and hydrophobic nature. Further, variation in temperature and concentration of DESs or SARA are explicitly considered. The structural variations are incorporated by estimating the critical properties in Lydersen–Joback–Reid framework using group contribution methodology. Cohesion based equation of state is used to estimate the density of SARA and DES. Geometric similitude concept in conjunction with cubic equation of state is used to estimate the surface tension and viscosity of DES and SARA. Later six different formulations namely, Arrhenius, Power law model, Lobe, Cragoe, Double-log, and Lederer model are employed to calculate the mixture viscosity of DES-SARA system.

Insights into CO2 huff-n-puff mechanisms from laboratory experiment and single-well pilot test in the Lucaogou tight oil reservoir, Jimsar sag, China

CO2 huff-n-puff has been accepted as an effective technique to improve oil recovery in tight oil reservoirs. Even though CO2 EOR mechanisms were extensively investigated from laboratory experiments, the links of experimental results to field-scale performance have not been widely investigated as few pilot tests were conducted. In this study, laboratory experiments and CO2-huff-n-puff pilot test were performed. First, phase behaviors of the Lucaogou crude oil and oil-CO2 mixtures were investigated via Pressure-Volume-Temperature (PVT) tests including flash evaporation, constant composition extension (CCE), and CO2 injection and slim tube tests, respectively. Experimental results showed that due to the higher concentration of the intermediate components, the saturation pressure of the Lucaogou crude oil is 6.18 MPa, which is much smaller than the initial and current formation pressures. The oil viscosity decreased from 24.8 mPa s to 3.0 mPa s and swelling factor increased to 1.848 after about 85 mol% CO2 dissolved. Moreover, slim tube test showed the minimum miscible pressure of the Lucaogou crude oil is 24.28 MPa, which is smaller than the current formation pressure, indicating multi-contact miscibility could be reached easily. Second, fracturing fluid imbibition and CO2 huff-n-puff experiments were carried out to evaluate the performance of CO2 EOR after fracturing. The oil recovery factor increased after imbibition time and the number of huff-n-puff cycles, and was impacted by petrophysical properties, like porosity and pore structure. In addition, performance of CO2 huff-n-puff pilot test in the J30 well was reported. Approximately 1.9% of original oil in place was recovered after one huff-n-puff cycle, showing a significant potential of CO2 EOR in the Lucaogou tight formation. Analysis of oil production rate, composition and density of produced oil shows the dominant EOR mechanisms in the early production stage were miscibility and CO2 vaporization, then viscosity reduction. Findings from this study will provide insights on CO2 EOR in tight oil reservoirs.

Natural Compounds Purified from the Leaves of Aristotelia chilensis: Makomakinol, a New Alkaloid and the Effect of Aristoteline and Hobartine on NaV Channels.

Aristotelia chilensis or "maqui" is a tree native to Chile used in the folk medicine of the Mapuche people as an anti-inflammatory agent for the treatment of digestive ailments, fever, and skin lesions. Maqui fruits are black berries which are considered a "superfruit" with notable potential health benefits, promoted to be an antioxidant, cardioprotective, and anti-inflammatory. Maqui leaves contain non-iridoid monoterpene indole alkaloids which have previously been shown to act on nicotinic acetylcholine receptors, potassium channels, and calcium channels. Here, we isolated a new alkaloid from maqui leaves, now called makomakinol, together with the known alkaloids aristoteline, hobartine, and 3-formylindole. Moreover, the polyphenols quercetine, ethyl caffeate, and the terpenes, dihydro-β-ionone and terpin hydrate, were also obtained. In light of the reported analgesic and anti-nociceptive properties of A. chilensis, in particular a crude mixture of alkaloids containing aristoteline and hobartinol (PMID 21585384), we therefore evaluated the activity of aristoteline and hobartine on NaV1.8, a key NaV isoform involved in nociception, using automated whole-cell patch-clamp electrophysiology. Aristoteline and hobartine both inhibited Nav1.8 with an IC50 of 68 ± 3 µM and 54 ± 1 µM, respectively. Hobartine caused a hyperpolarizing shift of the voltage-dependence of the activation, whereas aristoteline did not change the voltage-dependence of the activation or inactivation. The inhibitory activity of these alkaloids on NaV channels may contribute to the reported analgesic properties of Aristotelia chilensis used by the Mapuche people.

Solution-processable polytriazoles from spirocyclic monomers for membrane-based hydrocarbon separations.

The thermal distillation of crude oil mixtures is an energy-intensive process, accounting for nearly 1% of global energy consumption. Membrane-based separations are an appealing alternative or tandem process to distillation due to intrinsic energy efficiency advantages. We developed a family of spirocyclic polytriazoles from structurally diverse monomers for membrane applications. The resulting polymers were prepared by a convenient step-growth method using copper-catalysed azide-alkyne cycloaddition, providing very fast reaction rates, high molecular weights and solubilities in common organic solvents and non-interconnected microporosity. Fractionation of whole Arabian light crude oil and atmospheric tower bottom feeds using these materials enriched the low-boiling-point components and removed trace heteroatom and metal impurities (comparable performance with the lighter feed as the commercial polyimide, Matrimid), demonstrating opportunities to reduce the energy cost of crude oil distillation with tandem membrane processes. Membrane-based molecular separation under these demanding conditions is made possible by high thermal stability and a moderate level of dynamic chain mobility, leading to transient interconnections between micropores, as revealed by the calculations of static and swollen pore structures.

Novel Biodegradable Chelating Agents for Micronutrient Fertilization.

Serious concerns about the negative impact of ethylenediaminetetraacetic acid (EDTA) on the environment resulted in severe restrictions imposed on this compound in many countries. One of the main concerns is related to the use of EDTA in agriculture as a chelator in microelement fertilizers: being introduced directly into the sawing fields, it penetrates into groundwater, with no chance to be captured/recycled. Respectively, there is an active search for environmentally friendly, biodegradable alternatives for this chelator. In this study, we proposed a biodegradable chelating agent, 2-((1,2-dicarboxyethyl)amino)pentanedioic acid (IGSA). It was synthesized in accordance with the principles of "green chemistry" from readily available nonhazardous precursors using water as a solvent; in addition, the method yields literally no waste. The synthesized chelator in the form of the crude reaction mixture was further used for preparing a multicomponent micronutrient fertilizer (B, Zn, Fe, Cu, Mn, and Mo). The fertilizer was shown to be highly biodegradable (72% in 28 days), while the EDTA-based product degraded only by 13%. The plant growing efficiency was tested on lettuce in the greenhouse experiments. The results were compared against the known commercial fertilizers based on EDTA and iminodisuccinic acid (IDS). The newly developed IGSA-based fertilizer significantly outperformed the EDTA-based fertilizer in lettuce biomass (1.4 and 1.6 times for root and foliar application, respectively). The total mineral uptake was almost two times higher (1.9 and 1.8 times for root and foliar treatments, respectively) compared to the EDTA-based complex and even slightly higher (1.2 and 1.1 times, respectively) compared to the IDS-based complex. Our work opens the doors for the industrial scale production and application of this fully "green", inexpensive microelement fertilizer that has the potential to replace the EDTA-based products.

Review on NMR as a tool to analyse natural products extract directly: Molecular structure elucidation and biological activity analysis.

Natural products, the small organic molecules produced by plants, microbes and invertebrates, often present in the form of a mixture, this leads to the structural characterisation of natural extracts often requiring time-consuming multistep purification procedures. Nuclear magnetic resonance (NMR) technology is traditionally utilised as a tool for the structural elucidation of pure compounds. Contemporarily, an up-to-date trend in the application of NMR in natural product research is shifting to the direct NMR analysis of crude mixtures, to obtain molecular structure and biological activity information without performing cumbersome separation. To review works of literature on the evolution, principle and progress of NMR technologies for analysing mixtures, we focus on the successful application of NMR technologies in direct analysis of natural product extracts. Based on our research experience, academic tracking and extensive literature search, which involved, but not limited to, the use of various databases, like Web of Knowledge and PubMed. The keywords used, in various combinations, to retrieve recent literature on the successful application of NMR technologies to sheer natural product extracts, and excluded artificially natural product mixture and biofluid. NMR technologies for direct natural extracts analysis, including two-dimensional J-resolved spectroscopy (2D-JRES), pure shift NMR, diffusion-ordered NMR spectroscopy (DOSY), statistical correlation spectroscopy (STOCSY), concentration-ordered NMR spectroscopy (CORDY), saturation transfer difference (STD) and water-ligand observed via gradient spectroscopy (WaterLOGSY) were illustrated. By these methods, molecular structure and biological activity information will be directly obtained from NMR analysis of natural products extract, aiming to save experimental time and expenses.