Nuclear Magnetic Resonance Spectroscopy Techniques Research Articles

Lithium-ion Transport Properties in DMSO and TEGDME: Exploring the Influence of Solvation through Molecular Dynamics and Experiments.

This study explores the properties of aprotic electrolytes via the application of experimental methods, including nuclear magnetic resonance spectroscopy and electrochemical techniques, along with molecular dynamic modeling. The aim is to provide a quantitative description of the physico-chemical properties of two well-established electrolytes (case studies), each exhibiting significantly distinct dielectric properties: a LiTFSI (Lithium bis(trifluoromethanesulfonyl)imide) solution in dimethyl sulfoxide (DMSO, dielectric constant= 46.68) and a LiTFSI solution in tetraethylene glycol dimethyl ether (TEGDME,=7.71). We obtained a comprehensive insight into the properties of the electrolytes at both the macroscopic-collective and molecular levels with particular emphasis on the interactions between the Li ions and solvent molecules. We discovered remarkable disparities in the structural arrangements, solvation behaviors, and bulk-related properties of these electrolyte systems, particularly in response to temperature changes.

Electrosynthesis of Verdoheme and Biliverdin Derivatives Following Enzymatic Pathways.

Artificial syntheses of biologically active molecules have been fruitful in many bioinspired catalysis applications. Specifically, verdoheme and biliverdin, bearing polypyrrole frameworks, have inspired catalyst designs to address energy and environmental challenges. Despite remarkable progress in benchtop synthesis of verdoheme and biliverdin derivatives, all reported syntheses, starting from metalloporphyrins or inaccessible biliverdin precursors, require multiple steps to achieve the final desired products. Additionally, such synthetic procedures use multiple reactants/redox agents and involve multistep purification/extraction processes that often lower the yield. However, in a single step using atmospheric oxygen, heme oxygenases selectively generate verdoheme or biliverdin from heme. Motivated by such enzymatic pathways, we report a single-step electrosynthesis of verdoheme or biliverdin derivatives from their corresponding meso-aryl-substituted metalloporphyrin precursors. Our electrosynthetic methods have produced a copper-coordinating verdoheme analog in >80% yield at an applied potential of 0.65 V vs ferrocene/ferrocenium in air-exposed acetonitrile solution with a suitable electrolyte. These electrosynthetic routes reached a maximum product yield within 8 h of electrolysis at room temperature. The major products of verdoheme and biliverdin derivatives were isolated, purified, and characterized using electrospray mass spectrometry, absorption spectroscopy, cyclic voltammetry, and nuclear magnetic resonance spectroscopy techniques. Furthermore, X-ray crystallographic data were collected for select cobalt (Co)- and Cu-chelating verdoheme and metal-free biliverdin products. Electrosynthesis routes for the selective modification at the macrocycle ring in a single step are not known yet, and therefore, we believe that this report would advance the scopes of electrosynthesis strategies.

Preparation, Characterization, In silico and In vitro Antimicrobial Studies of Phenothiazine-3-sulphonamide Derivatives

The antibacterial activities of phenothiazine and sulphonamide derivatives have attracted so much interest. In this study, the synthesis and characterization of phenothiazine-3-sulphonamide derivatives and evaluation of their antimicrobial activity against the following pathogenic microorganisms is reported. Two Gram-positive bacteria; (Staphylococcus aureus (ATCC: 6538) and Streptococcus pyogenes (ATCC: 27853)), two Gram-negative bacteria; (Escherichia coli(ATCC: 3008), and Salmonella typhi (ATCC: 25175)) as well as one fungus (Aspergillus fumigatus (ATCC: 10231)) were used while ciprofloxacin, gentamycin and ketoconazole served as standard drugs. The synthesis of the derivatives was achieved through a base catalyzed the reaction of 4-chloroaniline with 1-naphthylamine to form 1-(naphthalen-1-yl)benzene-1,4-diamine. This intermediate was then treated with sulphur and iodine to yield the phenothiazine derivative while subsequent treatment of the phenothiazine compound with sulphonyl chlorides gave the final products. The synthesized compounds were characterized via proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR) and Fourier-transform infrared (FTIR) spectroscopic techniques. The minimum inhibitory concentration (MIC) of each compound was then determined using the agar well diffusion method. To predict the binding energies and patterns of the synthesized compounds with target proteins of the above-mentioned microorganisms, molecular docking simulations were run using Autodock Vina software (version 4.2). The spectra data of the compounds for FTIR, 1H-NMR and 13C-NMR spectral data were consistent with the assigned structures of the synthesized compounds. The binding energies (kcal/mol) for in silico antimicrobial studies were in the range -5.1 to -7.6 kcal/mol. The MIC values were in the range 3.5 to 1.0 mg/L. The results of the in vitro test revealed that the synthesized compounds exhibit promising antimicrobial activity and showed excellent bactericidal and fungicidal activities. The results obtained showed that the synthesized compounds possess drug-like properties and are good starting materials for drug production.

Monitoring the Geopolymerization Reaction of Geopolymer Foams Using 29Si and 27Al MAS NMR

This study aims to investigate the geopolymerization reaction of geopolymer foams produced with three different foaming agents: aluminum powder, zinc powder, and hydrogen peroxide. The geopolymerization reaction of geopolymer foam was monitored using the 27Al and 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy technique. 27Al MAS-NMR was used to monitor the reaction at an early stage, while 29Si and 27Al MAS-NMR analyses were employed at specific time intervals of 3, 6, 10, 15, and 28 days to examine the changes that occurred in the formed gel over time. We discussed in detail how the type of foaming agent used and the duration of the reaction both influence the quantity of gel formed and the amount of remnant fly ash. Our findings indicate that the type of foaming agent used affects the formation and structure of the gel, with aluminum powder leading to the highest gel formation. Additionally, the duration of the reaction plays a significant role in determining the quantity of remnant fly ash, with longer reaction times resulting in decreased fly ash content. This study sheds light on the relevance of understanding the role of foaming agents in the geopolymerization reactions of geopolymer foams and the influence of reaction time on the formed gel properties.

Magic Angle Spinning Solid-State 13C Photochemically Induced Dynamic Nuclear Polarization by a Synthetic Donor-Chromophore-Acceptor System at 9.4 T.

Solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) is a nuclear magnetic resonance spectroscopy technique in which nuclear spin hyperpolarization is generated upon optical irradiation of an appropriate donor-acceptor system. Until now, solid-state photo-CIDNP at high magnetic fields has been observed only in photosynthetic reaction centers and flavoproteins. In the present work, we show that the effect is not limited to such biomolecular samples, and solid-state 13C photo-CIDNP can be observed at 9.4 T under magic angle spinning using a frozen solution of a synthetic molecular system dissolved in an organic solvent. Signal enhancements for the source molecule larger than a factor of 2300 are obtained. In addition, we show that bulk 13C hyperpolarization of the solvent can be generated via spontaneous 13C-13C spin diffusion at natural abundance.

The Use of Spectroscopic Methods to Study Organic Matter in Virgin and Arable Soils: A Scoping Review

The use of modern spectroscopic methods of analysis, which provide extensive information on the chemical nature of substances, significantly expands our understanding of the molecular composition and properties of soil organic matter (SOM) and its transformation and stabilization processes in various ecosystems and geochemical conditions. The aim of this review is to identify and analyze studies related to the application of nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy techniques to study the molecular composition and transformation of organic matter in virgin and arable soils. This article is mainly based on three research questions: (1) Which NMR spectroscopy techniques are used to study SOM, and what are their disadvantages and advantages? (2) How is the NMR spectroscopy technique used to study the molecular structure of different pools of SOM? (3) How is ESR spectroscopy used in SOM chemistry, and what are its advantages and limitations? Relevant studies published between 1996 and 2024 were searched in four databases: eLIBRARY, MDPI, ScienceDirect and Springer. We excluded non-English-language articles, review articles, non-peer-reviewed articles and other non-article publications, as well as publications that were not available according to the search protocols. Exclusion criteria for articles were studies that used NMR and EPR techniques to study non-SOM and where these techniques were not the primary methods. Our scoping review found that both solid-state and solution-state NMR spectroscopy are commonly used to study the structure of soil organic matter (SOM). Solution-phase NMR is particularly useful for studying soluble SOM components of a low molecular weight, whereas solid-phase NMR offers advantages such as higher 13C atom concentration for stronger signals and faster analysis time. However, solution-phase NMR has limitations including sample insolubility, potential signal aggregation and reduced sensitivity and resolution. Solid-state NMR is better at detecting non-protonated carbon atoms and identifying heterogeneous regions within structures. EPR spectroscopy, on the other hand, offers significant advantages in experimental biochemistry due to its high sensitivity and ability to provide detailed information about substances containing free radicals (FRs), aiding in the assessment of their reactivity and transformations. Understanding the FR structure in biopolymers can help to study the formation and transformation of SOM. The integration of two- and three-dimensional NMR spectroscopy with other analytical methods, such as chromatography, mass spectrometry, etc., provides a more comprehensive approach to deciphering the complex composition of SOM than one-dimensional techniques alone.

Optoelectronic Response to the Fluor Ion Bond on 4-(4,4,5,5-Tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde.

Boronate esters are a class of compounds containing a boron atom bonded to two oxygen atoms in an ester group, often being used as precursors in the synthesis of other materials. The characterization of the structure and properties of esters is usually carried out by UV-visible, infrared, and nuclear magnetic resonance (NMR) spectroscopic techniques. With the aim to better understand our experimental data, in this article, the density functional theory (DFT) is used to analyze the UV-visible and infrared spectra, as well as the isotropic shielding and chemical shifts of the hydrogen atoms 1H, carbon 13C and boron 11B in the compound 4-(4,4,5,5-tetramethyl-1,3,2-dioxoborolan-2-yl)benzaldehyde. Furthermore, this study considers the change in its electronic and spectroscopic properties of this particular ester, when its boron atom is coordinated with a fluoride anion. The calculations were carried out using the LSDA and B3LYP functionals in Gaussian-16, and PBE in CASTEP. The results show that the B3LYP functional gives the best approximation to the experimental data. The formation of a coordinated covalent B-F bond highlights the remarkable sensitivity of the NMR chemical shifts of carbon, oxygen, and boron atoms and their surroundings. Furthermore, this bond also highlights the changes in the electron transitions bands n → π* and π → π* during the absorption and emission of a photon in the UV-vis, and in the stretching bands of the C=C bonds, and bending of BO2 in the infrared spectrum. This study not only contributes to the understanding of the properties of boronate esters but also provides important information on the interactions and responses optoelectronic of the compound when is bonded to a fluorine atom.

Isolation and Identificationof Octadecane-3-on Compound From Ethyl Acetate Fraction of Momordica balsamina L. Leaves

Momordica balsamina L. is a wild plant that generally grows in moist soil and gets a lot of sunlight. The leaves and fruit are reported to have various medicinal and nutritional properties. This study aimed to isolate and identify the compounds contained in the ethyl acetate fraction in Momordica balsamina L The isolation stage was carried out by the maceration method and the separation and purification of the compounds using gravity column chromatography methods to obtain isolate fraction F1.6.2 with a sample weight of 2.4 mg. Identification of compounds using proton nuclear magnetic resonance (1H-NMR) and carbon nuclear magnetic resonance (13C-NMR) spectroscopy techniques. The proposed identified compound is octadecan-3-one or 3-octadecanone with the molecular formula C18H36O

Antioxidant and enzyme inhibitory potentials of phytochemicals isolated from Dioclea reflexa (Hook F.) stem: in-vitro and in-silico studies

The objective of the study was to isolate and characterize phytochemicals from the stem extract of D. reflexa and investigate their biochemical activities. Five flavonoids together with two terpenoids, were isolated. Their structures were identified using 1D and 2D nuclear magnetic resonance (NMR) and mass spectroscopic techniques in combination with circular dichroism (CD) spectroscopy, as well as comparisons with published data. The in vitro reactive oxygen species scavenging potential of the compounds was investigated. The lipoxygenase and urease inhibitory potential of the compounds were tested using in vitro and in silico methods. Compound 1 and 2 exhibited potent antioxidant activity with lower IC50 values of 38.5 ± 0.25 and 39.5± 0.14 μM respectively compared with the standard used (BHA IC50 value = 39.5± 0.14) in DPPH assay. Compound 1 and 2 also exhibit good reducing ability and superoxide radical scavenging activity reflected by IC50 value 44.6 ± 0.30 and 48.5 ± 0.16 respectively compared with BHA (IC50 45.6 ± 0.54). Compound 2 and 3 showed significant inhibitory effect against urease with IC50 values 26.2 ± 0.29 μM and 36.5 ± 0.37 μM respectively, while compound 4 with IC50 value 33.3 ± 0.74 μM is the most active against lipoxygenase. All the seven compounds showed varying degrees of binding affinity against the targets with compounds 1–5 having the better docking score compared with the co-crystalized ligands of both lipoxygenase and urease. The density functional theory reveals the replicate of the transitional state between the compounds and their respective receptor and stability of the compounds was predicted from the energy gap (ELUMO – EHOMO). These compounds are potential drug against stomach ulcers, inflammation and oxidative stress associated diseases. It is also worth mentioning that the complete assignments of NMR data 1 and 2 were reported for the first time in this study.

LC-HRMS and NMR studies for the characterization of degradation impurities of ubrogepant along with the in silico approaches for the prediction of degradation and toxicity

Ubrogepant is the first oral calcitonin gene-related peptide (CGRP) receptor antagonist which is used for the acute treatment of migraine in adults. The present study employs liquid chromatography-high resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance spectroscopy (NMR) techniques for the identification and characterization of degradation impurities of ubrogepant. The forced degradation study of ubrogepant was performed as per the International Council for Harmonisation (ICH) Q1A and Q1B guidelines. The in silico degradation profile of ubrogepant was predicted by Zeneth. It was observed that ubrogepant was labile to acidic hydrolysis, basic hydrolysis, and oxidative degradation conditions (H2O2), although it was stable in neutral hydrolysis and photolytic (UV light and visible light) conditions. Eight degradation impurities were formed, which were separated on reversed-phase HPLC with a gradient program on an InertSustain C8 column (4.6 × 250 mm, 5 µm) using 10 mM ammonium formate (pH unadjusted) and acetonitrile as the mobile phase. The structures of all the degradation impurities were characterized using the exact masses obtained from the HRMS/MS. Further, NMR studies were conducted on two major degradation impurities (UB-4 and UB-7). A plausible mechanism was proposed to support the structures of all the degradation impurities of UBR. In silico toxicity and mutagenicity assessment were done by DEREK Nexus, SARAH Nexus, and ProTox-II.

Mechanistic Insights into the Inhibition of a Common CTLA-4 Gene Mutation in the Cytoplasmic Domain.

Cytotoxic T-lymphocyte antigen 4 (CTLA-4) is a pivotal immune checkpoint receptor, playing a crucial role in modulating T-cell activation. In this study, we delved into the underlying mechanism by which a common mutation, G199R, in the cytoplasmic domain of CTLA-4 impacts its inhibitory function. Utilizing nuclear magnetic resonance (NMR) spectroscopy and biochemical techniques, we mapped the conformational changes induced by this mutation and investigated its role in CTLA-4 activity. Our findings reveal that this mutation leads to a distinct conformational alteration, enhancing protein-membrane interactions. Moreover, functional assays demonstrated an improved capacity of the G199R mutant to downregulate T-cell activation, underscoring its potential role in immune-related disorders. These results not only enhance our understanding of CTLA-4 regulatory mechanisms but also provide insights for targeted therapeutic strategies addressing immune dysregulation linked to CTLA-4 mutations.

First comprehensive untargeted metabolomics study of suramin-treated Trypanosoma brucei: an integrated data analysis workflow from multifactor data modelling to functional analysis.

Human African trypanosomiasis, commonly known as sleeping sickness, is a vector-borne parasitic disease prevalent in sub-Saharan Africa and transmitted by the tsetse fly. Suramin, a medication with a long history of clinical use, has demonstrated varied modes of action against Trypanosoma brucei. This study employs a comprehensive workflow to investigate the metabolic effects of suramin on T. brucei, utilizing a multimodal metabolomics approach. The primary aim of this study is to comprehensively analyze the metabolic impact of suramin on T. brucei using a combined liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance spectroscopy (NMR) approach. Statistical analyses, encompassing multivariate analysis and pathway enrichment analysis, are applied to elucidate significant variations and metabolic changes resulting from suramin treatment. A detailed methodology involving the integration of high-resolution data from LC-MS and NMR techniques is presented. The study conducts a thorough analysis of metabolite profiles in both suramin-treated and control T. brucei brucei samples. Statistical techniques, including ANOVA-simultaneous component analysis (ASCA), principal component analysis (PCA), ANOVA 2 analysis, and bootstrap tests, are employed to discern the effects of suramin treatment on the metabolomics outcomes. Our investigation reveals substantial differences in metabolic profiles between the control and suramin-treated groups. ASCA and PCA analysis confirm distinct separation between these groups in both MS-negative and NMR analyses. Furthermore, ANOVA 2 analysis and bootstrap tests confirmed the significance of treatment, time, and interaction effects on the metabolomics outcomes. Functional analysis of the data from LC-MS highlighted the impact of treatment on amino-acid, and amino-sugar and nucleotide-sugar metabolism, while time effects were observed on carbon intermediary metabolism (notably glycolysis and di- and tricarboxylic acids of the succinate production pathway and tricarboxylic acid (TCA) cycle). Through the integration of LC-MS and NMR techniques coupled with advanced statistical analyses, this study identifies distinctive metabolic signatures and pathways associated with suramin treatment in T. brucei. These findings contribute to a deeper understanding of the pharmacological impact of suramin and have the potential to inform the development of more efficacious therapeutic strategies against African trypanosomiasis.

Isolation and identification of forced degradation products of Febuxostat

AbstractThe current study explains the degradation behavior of Febuxostat API, a non‐purine xanthine oxidase inhibitor used to treat hyperuricemia. A degradation study was carried out as per the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines, and the study confirms that the Febuxostat is largely stable in thermal, photolytic, oxidative, and basic hydrolytic conditions and labile in acid hydrolysis conditions. There were four different degradation products (DPs) found during acid hydrolysis; of these, DPs 2, 3, and 4 are new and have never been reported before, while DP 1 is known and has already been published. All these DPs were identified using ultra‐high‐performance liquid chromatography‐mass spectrometry (UHPLC‐MS) analysis, purified by using preparative HPLC, and characterized using high‐resolution mass spectrometry (HRMS) and nuclear magnetic resonance (NMR) spectroscopy techniques. The formed DPs are by the hydrolysis of the cyano functional group of Febuxostat and the esterification of DP‐1 under acidic conditions. All DP's structural characterization was carried out using NMR spectroscopy and HRMS. The present study describes concrete confirmation of DP structures and it explains the stability behavior of the Febuxostat. The current method is also used to identify DPs with shorter runtime in the future.

On-water Catalyst-free Synthesis of 3-Alkenyl Oxindoles

3-Alkenyl oxindoles are key structural motifs in organic chemistry with a wide range of applications mainly in the pharmaceutical industry, due to excellent biological activities such as anti-inflammatory, antiviral, antibacterial, and anticancer properties. With the discovery of the importance of oxindole derivatives in the pharmaceutical industry, demand for sustainable protocols for the synthesis increased as most classical methods have their limitations and flaws. In this study on-water, catalyst-free, atom-economical green approach was developed for the synthesis of 3- alkenyl oxindole derivatives using oxindole and aldehyde as starting materials. The reaction between oxindole and benzaldehyde was conducted on water under catalyst-free conditions. Interestingly, 100% conversion was observed when the reaction was carried out for 24 hours at 100° C. As the next step, the applicability of the developed approach was proven for different aldehydes. Furaldehyde, cinnamaldehyde, and vanillin were used as the aldehydes to synthesize 3- alkenyl oxindole derivatives, and the isolated yields were obtained as 77%, 54%, and 51% respectively. The desired product formation was confirmed by comparing the Rf value of the product with that of the previously synthesized well-characterized compounds; 3- benzylideneindolin-2-one, 3-(furan-3-methylene)indolin-2-one, 3-(3-phenylallylidene)indolin-2- one, and 3-(4-hydroxy-3-methoxybenzylidene)indolin-2-one using Thin Layer Chromatography. Further characterization was done by Fourier-transform infrared (FT-IR), Ultraviolet-visible (UVVis), and Nuclear Magnetic Resonance (NMR) spectroscopic techniques. In further optimization steps, the reaction was performed using surfactants as the catalyst. By adhering to the green chemistry principles different sources of biosurfactants were used including Acacia concinna pods, Sapindus emarginatus fruit pericarp, Dillenia retusa fruit pericarp, and Trigonella foenumgraecum seeds. In order to compare the effect of biosurfactants, a synthetic surfactant, sodium dodecyl sulfate (SDS) was used as the catalyst. When the reaction was carried out for 21 hours at 100 °C using fruit pericarp of Sapindus emarginatus as the source of biosurfactant, 100% conversion was observed. Using water as the solvent, readily available starting materials, higher yield, and eco-friendliness and catalyst-free conditions suggest the possible use of the developed method for large-scale preparations of 3-alkenyl oxindole derivatives.
 Keywords: Green protocol, Oxindole derivatives, Surfactant, On water synthesis, Catalyst-free

Formulation Studies with Cyclodextrins for Novel Selenium NSAID Derivatives.

Commercial cyclodextrins (CDs) are commonly used to form inclusion complexes (ICs) with different molecules in order to enhance their water solubility, stability, and bioavailability. Nowadays, there is strong, convincing evidence of the anticancer effect of selenium (Se)-containing compounds. However, pharmaceutical limitations, such as an unpleasant taste or poor aqueous solubility, impede their further evaluation and clinical use. In this work, we study the enhancement of solubility with CD complexes for a set of different nonsteroidal anti-inflammatory drug (NSAID) derivatives with Se as selenoester or diacyl diselenide chemical forms, with demonstrated antitumoral activity. The CD complexes were analyzed via nuclear magnetic resonance (NMR) spectroscopic techniques. In order to obtain additional data that could help explain the experimental results obtained, 3D models of the theoretical CD-compound complexes were constructed using molecular modeling techniques. Among all the compounds, I.3e and II.5 showed a remarkable increase in their water solubility, which could be ascribed to the formation of the most stable interactions with the CDs used, in agreement with the in silico studies performed. Thus, the preliminary results obtained in this work led us to confirm the selection of β and γ-CD as the most suitable for overcoming the pharmaceutical drawbacks of these Se derivatives.

Isolation, identification, and characterization of potential biosurfactant-producing bacteria from processing wastewater for the development of eco-friendly green technology

Exploring novel biosurfactants (BS) has become a critical focus in biotechnology research. While BS provides eco-friendly substitutes to chemical surfactants, there is a need to identify high-potential BS-producing bacteria. Currently, the sustainable development of BS-based technologies is hindered by the lack of systematic exploration and understanding of microbial diversity for BS production. This study aims to isolate and identify novel BS isolated from different strains and elucidate their chemical structures for assessing their potential applications. Eleven BS-producing bacteria were isolated from processing wastewater (PWW). The strains were identified by 16S ribotyping and screened for BS production. The produced BS were characterized using Fourier transform infrared and nuclear magnetic resonance spectroscopic techniques. The results indicated that five strains produced a lipopeptide BS, while the other six strains produced glycolipid BS. According to the findings, eleven strains are distributed in eight genera indicating the high bacterial diversity in BS production.

Unlocking superior properties in polypropylene/polyethylene terephthalate (PP/PET) blends using an ethylene-butylene-acrylate terpolymer reactive compatibilizer

The increasing global plastic production has created an urgent demand for energy-efficient processes to transform mixed plastic waste into value-added products via upcycling. Compatibilization of polypropylene (PP) and poly(ethylene terephthalate) (PET), two used semi-crystalline polymers in industry, is investigated in this study. We evaluate the effectiveness of an ethylene-butylene-acrylate terpolymer (PTW) at different contents in a 70/30 PP/PET blend, examining the resulting physico-chemical characteristics. Adding PTW as compatibilizer significantly reduces the droplet size in the PP/PET blend, improving rheological and mechanical properties. Remarkably, the blend containing 1.5 % PTW exhibits maximum enhancement in mechanical properties. To understand deeply the chemical compatibilization mechanism, Fourier transform infrared spectroscopy (FTIR-ATR), Atomic Force Microscopy combined with infrared spectroscopy (AFM-IR), and Proton Nuclear Magnetic Resonance Spectroscopy (1H NMR) techniques were employed. The compatibilizer was located at the interphase, and the chemical reaction using AFM-IR and 1H NMR was tracked. These advanced techniques prove the chemical compatibilization mechanism in PP/PET blends with PTW. These findings contribute to understanding the compatibilization processes, offering valuable guidance for developing efficient upcycling processes for mixed plastic waste.

Development in gelatin-matrix composite films: The incorporation of vitamin C adducts enhances the optical behaviors of gelatin films†

The chemical cross-linking method continues to be widely recognized as the most efficient and popular strategy for modifying gelatin. However, the exploration of enhancing the optical and electrical characteristics of gelatins through the use of organic molecules is still in its early stages. In this investigation, two stable dopants of ascorbic acid adducts were synthesized via the smooth and facile procedure, and their identities were validated through Fourier transform-infrared (FT-IR) and nuclear magnetic resonance spectroscopy techniques, including FT-1H NMR, and FT-13C NMR. The novel gelatin-matrix composite films were fabricated by blending vitamin C adducts with various gelatins including pork gelatin (PG), fish gelatin (FG), bovine gelatin (BG), and chicken gelatin (CG) using the casting method. The chemical and homogenous interactions between dopants and gelatin matrixes were verified through several spectroscopic techniques. The XRD spectra of the composite films show a significant elevation in their amorphous structures when compared to the pure gelatin host. The FT-IR spectra of both the gelatin matrix and their composites demonstrate strong chemical interactions among the functional groups within the gelatin composite films. The UV–vis spectra provided the primary optical information for the synthesized hybrid film. Remarkably, the index of refraction (n) and dielectric loss (ɛi) magnitudes are raised, while the average optical band gap energy (Eg) decreased from 4.9 (pure gelatin) to 3.4 eV. By applying Tauc's model, we successfully recognized the direct electronic transition occurring between the valence band (VB) and the conduction band (CB). The results of our research highlights that minor changes in the adduct composition significantly impact optical and textural properties in polymer composites, offering a plethora of potential technological opportunities. These applications include materials packaging, blocking of harmful light, and encapsulation purposes.

Investigation of the lithiation mechanism of tin phosphite SnHPO3 as anode for Lithium-ion batteries

Phosphite-based anodes are attracting increasing attention in energy storage, especially for lithium-ion technology, due to their distinctive structures and their good electrochemical performances. Herein, the lithiation mechanism of tin phosphite SnHPO3 as lithium anode was examined for the first time. SnHPO3 has been synthesized through a soft hydrothermal route. Its structure was characterized by X-ray diffraction, Fourier Transform Infrared spectroscopy and 31P Nuclear Magnetic Resonance spectroscopy techniques. The reaction mechanisms of lithiation-delithiation of SnHPO3 anode was conducted using operando X-ray diffraction, ex-situ X-ray and ex-situ Fourier Transform Infrared spectroscopy techniques at room temperature. Both in-situ and ex-situ measurements show that SnHPO3 undergoes a conversion mechanism. The lithiation-delithiation of tin phosphite took place in a complex redox reaction sequence, and the reversible electrochemical phenomenon exclusively occurs through the alloying of tin at a low potential. The lithiation of tin phosphite begins by partial degradation of its structure, signifying the start of the conversion process. Then, the phosphite matrix becomes amorphous. The reversible capacity of the system is governed by the lithium‑tin alloying de-alloying process, produced at low potential.

Quinones: Biosynthesis, Characterization of 13 C Spectroscopical Data and Pharmacological Activities.

Quinones are natural products widely distributed in nature, which are involved in stages of several vital biological processes, with mostly having a variety of pharmacological properties. The main groups comprising most of these compounds are benzoquinones, naphthoquinones, anthraquinones, and phenanthraquinones. Quinone isolation has been a focus of study around the world in recent years; for this reason, this study approaches the junction of natural quinones identified by 13 C Nuclear Magnetic Resonance (NMR) spectroscopic analytical techniques. The methodology used to obtain the data collected articles from various databases on quinones from 2000 to 2022. As a result, 137 compounds were selected, among which 70 were characterized for the first time in the period investigated; moreover, the study also discusses the biosynthetic pathways of quinones and the pharmacological activities of the compounds found, giving an overview of the various applications of these compounds.