cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14304221
title: Spectrophotometric Determination of Allura Red AC and Tartrazine in Food Products Using Hydrophobic Deep Eutectic Solvents as an Environmentally Sustainable Micro-Extractor

description: This paper reports the application of hydrophobic deep eutectic solvents (HDES) as an environmentally friendly alternative for liquid-phase microextraction (LPME) of Allura Red AC and Tartrazine in food products and the spectrophotometric determination of these analytes. The HDES used in this work were prepared by mixing octanoic acid (OctAc) or decanoic acid (DecAc) and tetrabutylammonium bromide (N4444-Br) in a molar ratio of 2:1. An investigation was also carried out regarding the effects of sample pH, sample volume, HDES volume, and concomitants on the analytical performance of the proposed method. The analytical curves obtained for Allura Red AC and Tartrazine in octanoic acid (OctAc)-tetrabutylammonium bromide (N4444-Br) were in the linear concentration ranges of 0.05 to 2.00 mg L-1 and 0.04 to 2.14 mg L-1, with limits of detection of 0.005 and 0.004 mg L-1, respectively. The proposed technique was successfully applied for the determination of Allura Red AC and Tartrazine in food products.
DOI: 10.6084/m9.figshare.14304219
title: Crystal Structure and Hirshfeld Surface Analysis of 1,4-Pentadien-3-one, (1E,4E)-1,5-diphenyl-2-(2,4-dinitrophenyl)hydrazone

description: The compound 1,4-pentadien-3-one,(1E,4E)-1,5-diphenyl-2-(2,4-dinitrophenyl)hydrazone presents the molecular formula C23H18N4O4 and was prepared in an undergraduate laboratory. The hydrazone was synthesized from the condensation between dibenzalacetone and 2,4-dinitrophenylhydrazine (DNPH) and crystallized employing water/acetone liquid-liquid diffusion. The structure presents three aromatic rings connected by an unsaturated Y-shaped system. Dinitro substituted and one of the other aromatic rings are 15º out of a coplanarity, while the other phenyl group is almost orthogonal to the first (89º). The only observed classical hydrogen bonding is an intramolecular N-H···O. The supramolecular structure was analyzed employing the Hirshfeld surface and that is organized through C-H···O hydrogen bond and C-H···π, polar-π, and π-stacking. An interaction involving NO2···NO2 was also observed.
DOI: 10.6084/m9.figshare.14304216
title: HSCCC Separations of Rutin Esters Obtained by Enzymatic Reaction Catalyzed by Lipase

description: The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This work aims to use high-speed countercurrent chromatography (HSCCC) to isolate rutin esters produced by esterification reactions catalyzed by the immobilized lipase from Candida antarctica (Novozyme 435®). The lipase-catalyzed synthesis of rutin esters (R3-R18:2) in 2-methyl-2-butanol exhibited conversions that ranged from 16 to 40% and highest conversion for short chain fatty acids (R4-R12). After initial partitioning tests of the reaction mixture in different solvent proportions followed by thin layer chromatography (TLC) analysis, the biphasic solvent systems consisting in HEMWat (hexane/ethyl acetate/methanol/water) in different proportions were chosen to separate rutin esters. These esters were separated for the first time to the reaction mixture via HSCCC. This technique proved to be more advantageous than the traditionally one since it allowed quick isolation and high purity (≥ 90%) of the products. It also permitted a substrate recovery for reuse in other enzymatic reactions. Furthermore, the results add valuable information, specially concerning the structures elucidation of different rutin esters not previously described.
DOI: 10.6084/m9.figshare.14304215
title: Aqueous Extract of Cumaru (Dipteryx odorata) Seeds as Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

description: The corrosion inhibition of mild steel by aqueous extract of cumaru (Dipteryx odorata) seeds and its high molecular weight fraction (HMWF) was investigated in 1 mol L-1 HCl solution. The study was carried out through gravimetric essays, open circuit potential measurements, anodic and cathodic polarization curves and electrochemical impedance analyses, as well as morphological analysis of the mild steel by scanning electron microscopy. Gravimetric tests showed that the inhibition efficiency (IE) increased with immersion time and inhibitor concentration, reaching 98% of IE using 100 mg L-1 of the HMWF, after 6 h immersion time. The activation energy (Ea) increased with the addition of both inhibitors which characterizes a physical adsorption of the constituents of the aqueous extract of cumaru on the metal surface. Polarization curves indicated that both aqueous cumaru seeds extract and its HMWF act as mixed-type inhibitor. Impedance results showed a decrease in double layer capacitance (Cdl) and an increase in charge transfer resistance (Rct) evidencing a typically screening effect. The adsorption of molecules present in the aqueous extract of cumaru followed the Langmuir isotherm. The aqueous cumaru seeds extract was characterized by Fourier transform infrared spectroscopy (FTIR), 1H, 13C and 2D nuclear magnetic resonance (NMR).
DOI: 10.6084/m9.figshare.14304213
title: Synthesis, Spectroscopic Characterization, DFT Calculations and Preliminary Antifungal Activity of New Piperine Derivatives

description: Four new piperine derivatives, PC1-PC4, were synthesized, and their structures were fully characterized by infrared (IR) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopies. Quantum chemical calculations were performed using density functional theory (DFT) with the B3LYP-D3/6-31G(d,p) and 6-311+G(2d,p) basis sets. Electronic properties, such as the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) and some global chemical reactivity descriptors, were evaluated to study the reactivity and stability of the compounds. 1H and 13C NMR chemical shifts were calculated by using the gauge-invariant atomic orbital (GIAO) method and compared with experimental values. In addition, the compounds were evaluated in an antifungal study against Candida, Trichophyton and Microsporum strains, and only PC4 showed 70% inhibition in ten tested strains, with a minimum inhibitory concentration (MIC) ranging from 1.23-2.46 μmol mL-1 and a minimum fungicide concentration (MFC) ranging from 9.84-19.68 μmol mL-1, and presented a fungistatic effect.
DOI: 10.6084/m9.figshare.14304212
title: Identification of Synthetic Drugs on Seized Blotter Papers Using ATR-FTIR and PLS-DA: Routine Application in a Forensic Laboratory

description: Blotter papers seizures containing synthetic drugs have intensified over the last decades. These drugs were originally conceived as “legal” alternatives to traditional illicit drugs, designed to mimic their effects and circumvent control agencies. Reference methods for determining these substances on blotter papers are based on chromatographic techniques using mass spectrometry detection. However, these procedures are destructive, expensive, and time consuming. Some compounds are also thermolabile and not suitable for regular gas chromatography analyses. In this paper, two multivariate models were presented and incorporated in the routine of a forensic laboratory as a screening method. They were developed and validated using a representative dataset of 158 seizures analyzed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and a partial least squares-discriminant analysis (PLS-DA) model. The first model (model A) discriminates between samples with and without different types of drugs, and the second one (model B) discriminates between samples containing NBOMe and NBOH, two N-benzyl 2,5-dimethoxy substituted phenethylamine commonly incorporated into blotter papers. The proposed method is fast, non-destructive, and requires no sample preparation. Both models showed reliable results (misidentification errors &lt; 10%), presented good results in a real forensic laboratory routine, and can be updated to include new drugs.
DOI: 10.6084/m9.figshare.14304210
title: Complementary Performance of Organoselenides and Organotellurides as Antimicrobials Agents

description: Fungi and bacteria are well-known pathogens for plants, fruits, and animals, including humans. In this context, the prospection of antimicrobial agents is crucial to provide new alternatives for the treatment of microbial diseases. Hence, selenium- and tellurium-containing compounds are underexploited and herein, antimicrobial activity of several organochalcogenated compounds was evaluated against Gram-negative and Gram-positive bacteria and fungi. A direct comparison between Se- and Te-containing compounds was performed, as well as structure-activity relationship studies. Among assayed compounds, secondary Se-amines LQ16 and LQ20 and secondary Te-amine LQ28 showed excellent results against a variety of fungi, while primary Te-amine LQ10 demonstrated promising results against bacteria. These results suggest organoselenides and organotellurides may be used for the development of new antimicrobial agents.
DOI: 10.6084/m9.figshare.14304209
title: Structure-Physical Properties Relationship of Eutectic Solvents Prepared from Benzyltriethylammonium Chloride and Carboxylic Acids

description: Deep eutectic solvents (DESs) have attracted the attention of the researchers as alternative solvents due to desirable properties such as easy preparation and high thermal stability. In this work, it was reported the preparation of five DESs from benzyltriethylammonium chloride (BTEAC) as quaternary ammonium salt (QAS) and carboxylic acids (oxalic, malonic or benzoic) as hydrogen bonding donor (HBD), which four were not reported so far. Furthermore, it was presented the first type III liquid DES at room temperature from benzoic acid and shown by interaction energy calculations why the formation of benzyltriethylammonium chloride:benzoic acid (BTEAC:BA) is favored over choline chloride:benzoic acid (ChCl:BA). The optimized geometries showed the Cl···π interaction is determining for decreasing the freezing point of benzyltriethylammonium chloride:benzoic acid mixture. Infrared spectra showed evidence for the existence of hydrogen bonds in DESs. Physical (freezing point, density and refractive index), thermal (thermogravimetric analysis) and rheological characterizations were performed for all solvents. The structure of HBDs affected the results on all evaluated properties and proved that it could be tunable. The prepared DESs were stable thermically and can be used in a wide range of temperature. Finally, rheological studies showed that Newtonian or non-Newtonian behavior can be observed by the nature of HBD.
DOI: 10.6084/m9.figshare.14304203
title: Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer

description: The properties of lanthanides allow them to be used as contrast agents for magnetic resonance imaging, thereby helping to differentiate between tissues, organs, and pathologies more efficiently. Lanthanides contain thermosensitive energy levels that aid identification of cancer and healthy cells. This work investigates the GdVO4 matrix obtained by the non-hydrolytic sol-gel methodology and doped with the lanthanide ions Er3+ and Yb3+ at a 1:1 molar ratio. The efficiency of the optical parameters was analyzed on the basis of the Er3+ green emission after excitation in the infrared region, namely 980 nm. The temperature-dependent fluorescence intensity ratio (FIR) between the thermally coupled Er3+ levels (2H11/2 and 4S3/2 → 4I15/2) was evaluated. The Er3+ emission depended on the laser power. The calculated number of photons was 2 in this case. Temperatures ranging from 298.3 to 374.5 K were assessed, and the sensitivity varied from 1.2 to 1.9% K-1, respectively. The initial temperature was estimated.
DOI: 10.6084/m9.figshare.14304201
title: Theoretical Study of the Reactivity of Phenyl Radicals Toward Enol Acetates

description: Arylation reactions are an important class of reactions and allow the synthesis of natural and synthetic products. Despite the efficient, but high cost and toxic methodologies involving transition metals, radical arylations have gained importance after the advent of photoredox catalysis. Arylation of enol acetates is an important tool for obtaining aryl ketones but the scope of the reaction is limited to the pattern of substitution at phenyl radical and α-carbon of the enol. Theoretical calculations ((U)BHandHLYP/6-311G**) show that the polar effect is the key factor in this reaction. A good correlation of calculated rate constants with field effect explained why phenyl radicals with electron-withdrawing groups react faster toward enol acetate. The presence of alkyl groups at α carbon at the enol showed some influence of enthalpic effect but strong influence of steric effect, evidenced by great correlations with Taft and Charton parameters. Finally, substitution at β carbon showed no significant effect at reaction rates.
DOI: 10.6084/m9.figshare.14304200
title: Sample Preparation Using TMAH and Nitric Acid for Multielement Determination in Crustacean Samples by MIP OES

description: This study proposes a simple sample preparation procedure using tetramethylammonium hydroxide (TMAH) and nitric acid (HNO3) to determine Cr, Cu, Fe, K, Mg, Mn, and Zn concentrations in shrimp (Macrobrachium amazonicum) and crab (Ucides cordatus) samples from the Amazon region by microwave-induced plasma optical emission spectrometry (MIP OES). The sample solubilization was carried out employing TMAH and HNO3 using an ultrasound bath and a thermostatic water bath. The accuracy of the proposed procedure was performed using microwave-assisted digestion as comparative method. Certified fish protein reference material (DORM-4) and also addition recovery experiments were used to assess the accuracy of the proposed procedure and recoveries obtained were adequate, ranging from 91 to 106%. In this study, the use of TMAH and HNO3 simplified sample preparation, maintaining the identity of analytes and ensuring efficiency in determinations.
DOI: 10.6084/m9.figshare.14304197
title: Antileishmanial Acetylene Fatty Acid and Acetogenins from Seeds of Porcelia macrocarpa

description: In the present work five acetylene derivatives (1-5), including three unknowns (1, 3 and 4), were isolated from seeds of Porcelia macrocarpa (Annonaceae). The structures of isolated compounds were determined as docos-13-yn-21-enoic acid (1), 3-hydroxy-4-methylene-2-(eicos-11’-yn-19’-enyl)but-2-enolide (2), 3-hydroxy-4-methylene-2-(octadec-9’-yn-17’-enyl)but-2-enolide (3), 3-hydroxy-4-methylene-2-(hexadec-7’-yn-15’-enyl)but-2-enolide (4), and (2S,3R,4R)-3-hydroxy-4-methyl-2-(eicos-11’-yn-19’-enyl)butanolide (5) by analysis of nuclear magnetic resonance (NMR) and electrospray ionization high-resolution mass spectrometry (ESI-HRMS) data. Moreover, all isolated compounds demonstrated selectivity towards intracellular amastigotes of Leishmania (L.) infantum, especially 2-4 with 50% inhibitory concentration (IC50) values of 9.2, 10.4 and 11.0 µM, respectively, indicating superior activity of that determined to positive control miltefosine (IC50 of 17.8 µM). Furthermore, these compounds showed higher selectivity index (SI) in comparison with miltefosine. Since related acetylene fatty acid 1 displayed reduced antiparasitic potential (IC50 of 48.5 µM), the obtained results suggested that the γ-lactone plays an important role in the antileishmanial activity. However, 2-4 exhibited cytotoxicity to mammalian NCTC cells (CC50 ca. 80 µM), which could be a result of the presence of a conjugated carbonyl system in the lactone ring, since 5, the only acetogenin that presents the saturated ring, lacked mammalian cytotoxicity (CC50 &gt; 200 µM).
DOI: 10.6084/m9.figshare.14304195
title: Yellow Mombin (Spondias mombin L.) Seeds from Agro-Industrial Waste as a Novel Adsorbent for Removal of Hexavalent Chromium from Aqueous Solutions

description: The objective of this study was to develop a low-cost and eco-friendly adsorbent from agro-industrial waste for the removal of hexavalent chromium in the aqueous medium. The adsorbent (BMC) produced from yellow mombin (Spondias mombin L.) seeds was characterized by the determination of the chemical composition, thermal analysis (thermogravimetric (TG) analysis and differential thermal analysis (DTA)), Fourier transform infrared spectroscopy (FTIR), pH in suspension and determination of the point of zero charge (PZC). The presence of proteins, fats and carbohydrates (15.690, 1.004, and 73.706%, respectively) suggests that the material can be a promising adsorbent, given the availability of functional groups. The following conditions were set: pH 2.0, adsorbent mass 450 mg, and equilibrium was reached after 80 min. The maximum adsorption capacity was approximately 98%. Kinetic studies showed that the pseudo-second-order kinetic equation was the one that best adjusted to the experimental data. Under the conditions investigated, the Langmuir isotherm model described the best balance data, signaling the adsorption in monolayer. According to the results, it was found that the BMC showed an outstanding performance for the removal of CrVI ions and may become a viable and efficient alternative for the treatment of industrial effluents containing trace elements.
DOI: 10.6084/m9.figshare.14304194
title: Evaluation of the Seasonality and Extraction Method on the Polar Extracts of Croton grewioides Baill. by Chromatogram Fingerprinting and Isolation of a New Triglycosylated Flavonoid

description: Croton grewioides Baill. popularly known as “canelinha” or “canelinha-de-cheiro” has been used for the treatment of influenza, antitussive, febrifuge and headache; however, the study of its phytochemical composition is limited. The aim of this study was to investigate the effect of the extraction method and seasonality through leaf extracts of four accessions of Croton grewioides by fingerprint chromatograms aided by principal component analysis to analyze the differences and similarities among the samples. We aimed also to provide chemical characterization of isolated secondary metabolites using semi-preparative liquid chromatography. The results showed that only the chemical profile of the methanolic extracts of accessions 101 and 113 were influenced by the seasonality. For the first time, four flavonoids were isolated through semi-preparative chromatography in this species, characterized as quercetin 3-O-β-D-galactopyranosyl-(1→2)-α-L-rhamnopyranoside-(1→6)-α-L-rhamnopyranoside (1), quercetin 3-O-β-D-galactopyranosyl-(1→2)-α-apiopyranoside-(1→6)-α-L-rhamnopyranoside (2), quercetin 3-O-glucopyranoside (3) and 3-O-methyl-quercetin (4), the flavonoid (2) has been recognized as a new triglycosylated derivative.
DOI: 10.6084/m9.figshare.14304191
title: Development of a Methodology Based on Extraction Induced by Emulsion Breaking for Copper Determination in Gasohol by Graphite Furnace Atomic Absorption Spectrometry

description: The development of a method based on extraction induced by emulsion breaking (EIEB) aiming copper determination in gasohol using graphite furnace atomic absorption spectrometry (GF AAS) is reported. Emulsification of the gasohol samples was carried out using nitric acid solution, (1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol surfactant (Triton X-114), and ultrasound energy. The variables related to the extraction efficiency were optimized by multivariate approaches (two-level factorial fractional design and Doehlert design). The best results were obtained when the emulsion was formed with 5.0 mL of the sample, 0.200 mL of 2.4 mol L-1 HNO3, 0.100 mL of 10% Triton X-114 and 10 min of sonication. A fast and efficient emulsion breaking was performed at 90 ºC. A volume of 6.65 mL of the copper-rich hydroalcoholic phase was extracted, separated from the organic phase and analyzed. Under these conditions, the following analytical characteristics were obtained: 0.61 and 2.0 µg L-1 for limits of detection and quantification, respectively; precision (percentage of relative standard deviation, 10 µg L-1) of 2.8%; and analytical sensitivity of 0.011 L µg -1. Accuracy was assessed by spike tests, and values in the range of 95-110% were achieved. The method was applied in the determination of copper in Brazilian gasoline samples (gasohol with 27% ethanol).
DOI: 10.6084/m9.figshare.14304189
title: Morita-Baylis-Hillman Reaction with 7-Chloroquinoline Derivatives-New Compounds with Potential Anticancer Activity

description: Morita-Baylis-Hillman adducts (MBHA) is a class of polyfunctional molecules that has been standing out due to their versatility and expressive biological activities. Therefore, this paper describes the synthesis and antiproliferative activity of some new MBHA/7-choroquinoline hybrids. The Michael acceptors were obtained starting from 4,7-dichloroquinoline which were submitted to the Morita-Baylis-Hillman reaction with ortho, meta and para-nitrobenzaldehyde. The in vitro screening of the synthetized MBHA against NCI-H292, HCT-116 and MCF-7 cancer cells suggests the influence of the spacer chain in its inhibition potential. The 50% inhibitory concentration (IC50) obtained in the antiproliferative assay using MCF-7, HCT-116, HL-60 and NCI-H292 cancer cells indicate expressive cytotoxic potential of the adducts containing nitro group in the ortho position, with IC50 of 4.60 µmol L-1. MBHA/7-choroquinoline hybrids were more active than MBHA described in literature, indicating the improvement of the cytotoxic effect due to 7-chloroquinoline moiety in the molecular structure, with maximum selectivity index values of 11.89.
DOI: 10.6084/m9.figshare.14304186
title: Mineral Nutrients and Plant-Fungal Interaction in Cocoa Trees (Theobroma cacao L.)

description: An infection of the fungus Moniliophthora perniciosa in cocoa trees reduces productivity of the plant. In this study, the concentrations of mineral nutrients in healthy leaves and in leaves of vegetative broom of the cocoa plant were determined, and the relationship between the disease and the nutritional composition of the leaves was assessed. The samples were analyzed using the wet digestion method and the concentrations were determined by inductively coupled plasma optical emission spectrometry and the Kjeldahl method. Results indicate that leaves of vegetative broom have lower concentrations of Ca, Mg, S, Fe, Mn, and Ni than healthy leaves. Concentrations of P and Cu were lower in healthy leaves and higher in leaves of vegetative broom. In contrast, concentrations of K, N, and Zn were the same for both types of leaves. In short, plant-fungal interaction was reflected in the nutritional composition of the leaves, demonstrated by the differences in nutrient concentrations between healthy and infected leaf tissue.
DOI: 10.6084/m9.figshare.14304185
title: Properties of Cu-Co Composite Catalysts for Synthesis of Aliphatic Alcohols

description: Cu-Co-containing cellulose-based carbon composite materials (Cu-Co/Cel) were formed by a matrix isolation method. Using X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared-Fourier spectroscopy (IR-Fourier spectroscopy), and non-isothermal research methods, the physicochemical properties of the composites were established. The catalysts are nanosized particles distributed in a carbon matrix, containing fragments of a system of conjugated bonds (C=C-C=C) of various lengths. Cu-Co/Cel catalysts are active in the synthesis of alcohols from CO and H2, demonstrating high CO conversion (68%) and specific activity (17 mol CO gMe-1 s-1). Differences in the mechanism of alcohol formation from CO and H2 on cellulose-based composites and an oxide support (comparison catalyst) were shown by analyzing the distribution of synthesis products.