Propyl Research Articles

Characterization and Identification Compounds of Liquid Smoke from Used Tire Waste Pyrolysis

Research on compounds from liquid smoke resulting from the pyrolysis of used tire waste has been conducted. The results of tire pyrolysis produce liquid hydrocarbons and charcoal which can be utilized and developed into more useful materials or finished goods. This study aims to identify the compound components of liquid smoke resulting from the pyrolysis of used tire waste. The research begins with manufacturing a pyrolysis tool based on the principle of dry distillation. The pyrolysis process is carried out by heating at high temperatures. Liquid smoke analysis was carried out using GC-MS. In contrast, the components of the compound were identified and characterized by comparing the mass spectrum data obtained with the mass spectrum data in the GC-MS library. The results showed that the pyrolysis of 6 kg of used tires produced 1500 mL of liquid smoke. Analysis of liquid smoke by GC-MS produced 88 chromatogram peaks, with the most dominant peak height at peaks 3, 17, 37, 38, 72, and 73. The most dominant compound component identified by MS spectrum analysis is 2-propanone (peak 3), 4-methyl-2-pentanone (peak 17), ethyl-benzene (peak 37), 1,2-dimethyl-benzene (peak 38), 1-methyl-4-(1-methyl ethyl)-benzene (peak 72) and limonene (peak 73).

Thermophysical properties of 2-amino-2-methylpropan-1-ol + alkanol mixtures: Investigation of molecular interactions by insight of FT-IR spectroscopy

We report the experimental data of dynamic viscosity (η) and ultrasonic speed (u) for 2-amino-2-methylpropan-1-ol (AMP) (1) + alkanol (C1-C3) (2) at T = (298.15–318.15) K and 0.1 MPa pressure. The derived excess (or deviation in) properties like dynamic viscosity (Δη), speed of sound (Δu) and excess isentropic compressibility (κSE) were regressed through Redlich-Kister polynomial equation. The Δη values were analyzed in terms of an Ab-initio approach, to study the intermolecular interactions between the binary components. Our analysis indicated that compared to propanol, methanol and ethanol interact strongly with AMP and 2-propanol exhibited the weakest interactions with AMP owing to steric hindrance by branched propyl group. In addition, viscosity (η) values and ultrasonic speed (u) data were analyzed using the various thermodynamic models/correlations that agreed well with our experimental data. Furthermore, we analyzed the FT-IR spectra of pure components and their binaries and observed prevailing hydrogen bonding interactions between the N-atom and OH-group of AMP with the OH-group of alkanol. Our findings highlight the great bonding capability of AMP with lower alkanol due to its small size and linear shape and can provide information on designing effective binary mixtures (blended) solvents based on AMP for CO2 absorption.

直線的分子連結を実現するテトラフルオロスルファニル化合物群：合成と開拓

Isosterism and bioisosterism are concepts in molecular design of specialty materials and drugs compounds. Fluorine and fluorine-containing functional groups are often used as isosteres and bioisosteres. Fluorine atom (F) is the most suitable isostere of hydrogen atom (H). With regard to electronegativity, fluorine is also used as a good substitute for hydroxyl (OH) group. Trifluoromethyl (CF3) group can be used as an equivalent for methyl or isopropyl groups, and difluoromethyl (-CF2H) group is an alcohol (-OH) equivalent. Pentafluoro-λ6-sulfanyl (SF5) group has recently attracted attention as a super CF3 group. This review introduces an undeveloped fluorine-containing functional group, tetrafluoro-λ6-sulfanyl (SF4) moiety. The SF4 is a unit consisting of four fluorine atoms bonded around an octahedral sulfur (VI) atom, with strong electron-withdrawing property and high lipophilicity. Characteristic of the SF4 unit are the cis- and trans-geometries connecting the two fragments. Interestingly, the trans-SF4 unit can connect two separated parts in a linear (180°) configuration via an octahedral sulfur center. Although organic compounds having an SF4 unit were known as early as the 1950s, their synthetic studies have been largely underdeveloped. We herein describe the structural and chemical characteristics of SF4-containing compounds, the background of the synthetic study, and their state-of-the-art synthetic constructions.

Conformational transformation of N-[arylsulfonylimino(phenyl)methyl]-1,4-benzoquinonemonoimines

It was established that in the solutions of N-[arylsulfonylimino(phenyl)methyl]-1,4-benzoquinonemonoimines there are both Z,E-isomerization relative to C=N bonds and atropoisomerism (inhibited rotation around the =N1–C= bond). The latter can be detected when there are the diastereotopic isopropyl groups in the quinoid ring. The rate constants of this process were calculated by the method of analysis of the full line in the 1H NMR spectra. Activation thermodynamic parameters were determined on their basis. With the help of quantum-chemical calculations, we proved that the determined experimental barriers corresponded exactly to the inhibited rotation around the bond =N1–C=.

Isopropylcyclohexane pyrolysis at high pressure and temperature: Part 1- theoretical study

The thermal decomposition of isopropylcyclohexane (IPCH) has been investigated at the CBS-QB3 and CASSCF/MRCI levels of theory. The pyrolysis of IPCH follows a radical chain mechanism, which mainly includes the C–C bond scission, H-atom abstraction, dissociation of alkene and alkyl-cyclohexene, decomposition, and isomerization of alkyl-cyclohexane radicals, decomposition and isomerization of alkenyl radicals, and stepwise dehydrogenation of cyclic intermediates. The rate constants for all elementary reactions have been evaluated with conventional transition state theory (TST/VTST) in the temperature range of 800–2000 K. The energy barriers and rate constants have been compared with previous theoretical reports of other cyclohexanes (like cyclohexane, methylcyclohexane, and ethylcyclohexane) to see the effect of isopropyl group in the cyclohexane dissociation. The final products of IPCH thermal decomposition are methane (CH4), ethylene(C2H4), propylene (C3H6), 1,3-butadiene (1,3-C4H6), and 1,3-pentadiene (1,3-C5H8), benzene, cyclopentadiene etc. The main goal of this work has been to come up with a detailed description of the IPCH thermal decomposition using high-level quantum chemical methods and provide reliable kinetic information to help in understanding the results from shock tube investigations discussed in part 2 of this work.

SYNTHESIS OF CALIX[4]ARENES WITH FIXED CONFORMATION AS POTENTIAL INHIBITORS OF FIBRIN POLYMERIZATION

Aim. The purpose of the present study was to develop a method for the fixation of ‘fixed’ conformation for estimation of the impact of calix[4]arene structure on the efficacy of its anticoagulant activity. This was achieved by substitution of the lower rim of C-145 analogue. Methods.Calix[4]arene C-145F (compound 6) was obtained in 4 steps starting with Duff reaction. Calix[4]arene methylene-bis-phosphonic ester 3 was prepared via addition of diisopropylphosphite in presence of metallic sodium to the parent calix[4]arene aldehyde 2. Further steps included Mitsunobu reaction, that afforded dipropoxycalix[4]arene 5 with rather good yields (80%), following the hydrolysis step that resulted in compound 6 in almost quantitative yield. Modeling of 3D-structure of calix[4]arene C-145 and its analogue C-145F was performed in Maestro, Schrodinger software. Results. Using a 2D NMR-NOESY spectroscopy, we can observe a distinct cross-peak between an aromatic singlet with a chemical shift on 7.72 ppm and protons of isopropyl group with a chemical shift on 1.62 ppm, which are moved in the strong field. Conclusions. The easy method of the fixation of conus conformation of calix[4]arene cup will be useful for synthesis of novel functionally active compounds. We believe that further development and study of different calix[4]arenes will help scientists to obtain bioactive molecules that could be prospective anti-thrombotic drugs.

Isotope-Guided Metabolomics Reveals Divergent Incorporation of Valine into Different Flavor Precursor Classes in Chives.

Plants of the genus Allium such as chives, onions or garlic produce S-alk(en)yl cysteine sulfoxides as flavor precursors. Two major representatives are S-propenyl cysteine sulfoxide (isoalliin) and S-propyl cysteine sulfoxide (propiin), which only differ by a double bond in the C3 side chain. The propenyl group of isoalliin is derived from the amino acid valine, but the source of the propyl group of propiin remains unclear. Here, we present an untargeted metabolomics approach in seedlings of chives (Allium schoenoprasum) to track mass features containing sulfur and/or 13 C from labeling experiments with valine-13 C5 guided by their isotope signatures. Our data show that propiin and related propyl-bearing metabolites incorporate carbon derived from valine-13 C5 , but to a much lesser extent than isoalliin and related propenyl compounds. Our findings provide new insights into the biosynthetic pathways of flavor precursors in Allium species and open new avenues for future untargeted labeling experiments.

A consensual machine-learning-assisted QSAR model for effective bioactivity prediction of xanthine oxidase inhibitors using molecular fingerprints.

Xanthine oxidase inhibitors (XOIs) have been widely studied due to the promising potential as safe and effective therapeutics in hyperuricemia and gout. Currently, available XOI molecules have been developed from different experiments but they are with the wide structure diversity and significant varying bioactivities. So it is of great practical significance to present a consensual QSAR model for effective bioactivity prediction of XOIs based on a systematic compiling of these XOIs across different experiments. In this work, 249 XOIs belonging to 16 scaffolds were collected and were integrated into a consensual dataset by introducing the concept of IC50 values relative to allopurinol (RIC50). Here, extended connectivity fingerprints (ECFPs) were employed to represent XOI molecules. By performing effective feature selection by machine-learning method, 54 crucial fingerprints were indicated to be valuable for predicting the inhibitory potency (IP) of XOIs. The optimal predictor yields the promising performance by different cross-validation tests. Besides, an external validation of 43 XOIs and a case study on febuxostat also provide satisfactory results, indicating the powerful generalization of our predictor. Here, the predictor was interpreted by shapely additive explanation (SHAP) method which revealed several important substructures by mapping the featured fingerprints to molecular structures. Then, 15 new molecules were designed and predicted by our predictor to show superior IP than febuxostat. Finally, molecular docking simulation was performed to gain a deep insight into molecular binding mode with xanthine oxidase (XO) enzyme, showing that molecules with selenazole moiety, cyano group and isopropyl group tended to yield higher IP. The absorption, distribution, metabolism, excretion and toxicity (ADMET) prediction results further enhanced the potential of these novel XOIs as drug candidates. Overall, this work presents a QSAR model for accurate prediction of IP of XOIs, and is expected to provide new insights for further structure-guided design of novel XOIs.

The Indian perspective on the harmful substances found in sanitary napkins and their effects on the environment and human health.

In this study, hazardous substances in 5 different brands of sanitary napkins being used in India have been analysed through gas chromatography mass spectroscopy (GCMS). Concentration of chemicals such as volatile organic chemicals (VOCs) (acetone, iso propyl alcohol, toluene), persistent organic pollutant (dioxins and furans), phthalates and total chlorine present in sanitary napkin have been reported. Furthermore, amounts of plastic present per sanitary napkin and total plastic waste generation potential have been calculated. Additionally, data analysis was done to understand the health impacts of these hazardous chemicals on users and the environment. It has been found that Indian sanitary pads have higher concentration of hazardous chemicals, as compared to similar product being sold in developed countries like - USA, Europe and Japan. The values of total chlorine observed in 5 different brands were found to be in the range of 170 to 460 ppm; dioxins varied from 0.244 to 21.419 pg/g; furans varied from 0.07 to 0.563 pg/g; acetone varied from 351 to 429 ppm; isopropyl alcohol varied from 125 to 184 ppm; toluene varied from 2.91 to 3.21 ppb; concentration of two phthalates, DBP and DEHP varied from 57.3 to 127.8 and from 146.2 to 188.5, respectively. Plastic pollution potential of this waste is approximately 33,210 tons/year. Daily exposure volume (DEV) of dioxins varied from 2.295 to 2.266 pg TEQ/g and furan from 0.0616 to 0.0738 pg TEQ/kg/day, compared to safe TDI value < 0.7 TEQ/kg/day. Dioxin's value is around 3 times higher than the accepted TDI value, whereas furan is within acceptable limit. Daily exposure doses (DED) of DBP were observed in-between 4.24 and 9.47 μg/kg-bw/day, whereas the DEHP value varied from 0.541 to 0.698 μg/kg-bw/day.

Exposure to endocrine disrupters and cardiometabolic health effects in preschool children: Urinary parabens are associated with wider retinal venular vessels

Background and aimParabens are widely used as antimicrobial preservatives in personal care products. Studies investigating obesogenic or cardiovascular effects of parabens show discordant results, while data on preschool children are lacking. Paraben exposure during early childhood could have profound cardiometabolic effects later in life. MethodsIn this cross-sectional study paraben concentrations [methyl (MeP), ethyl (EtP), propyl (PrP), butyl (BuP)] were measured by ultra-performance liquid chromatography/tandem mass spectrometry in 300 urinary samples of 4-6-year-old children of the ENVIRONAGE birth cohort. Paraben values below the limit of quantitation (LOQ) were imputed by censored likelihood multiple imputation. The associations between log-transformed paraben values and cardiometabolic measurements (BMI z-scores, waist circumference, blood pressure and retinal microvasculature) were analyzed in multiple linear regression models with a priori selected covariates. Effect modification by sex was investigated by including interaction terms. ResultsGeometric means (geometric SD) of urinary MeP, EtP, and PrP levels above the LOQ were 32.60 (6.64), 1.26 (3.45), and 4.82 (4.11) μg/L, respectively. For BuP more than 96% of all measurements were below the LOQ. Regarding the microvasculature, we found direct associations between MeP and central retinal venular equivalent (β = 1.23, p = 0.039) and PrP with the retinal tortuosity index (x103)(β = 1.75, p = 0.0044). Furthermore, we identified inverse associations between MeP and ∑parabens with BMI z-scores (β = −0.067, p = 0.015 and β = −0.070, p = 0.014 respectively), and EtP with mean arterial pressure (β = −0.69, p = 0.048). The direction of association between EtP and BMI z-scores showed evidence for sex-specific differences with a direct trend in boys (β = 0.10, p = 0.060). ConclusionsAlready at young age paraben exposure is associated with potentially adverse changes in the retinal microvasculature.

Phytochemical Study of Volatile Oils for the Ocimum basilicum L. and Mentha spicata By Gas Chromatography Technique

This study emphasized on the identification and detection the secondary metabolism compounds different of volatile oils by Gas Chromatography Technique of Ocimum basilicum L. and Mentha spicata L plant from Labiate (Lamiaceae) family cultivated in Iraq by suxhlet apparatus. the medicinal importment acquired this study and to know the active compound in the volatile oil was identified in plant extract of aerial parts by Gas Chromatography Mass, The result showed that of (80g) of O.basilicum and M. spicata has produced volatile oil ( 2.5% and 3. 75%) respectively, The study has shown that essential oil of O.basilicum 25 compounds and had the highest compound concentration Estragole reaching it is percentage (23.46%) followed Cyclohexanol,5-methyl-2-(1methyl ethyl) (14.19%), Then Tetrapentaconate, 1,54-dibromo compound concentration (8.99%). concentration the M. spicata, the study showed that it contain 25 compound and that the compound Isopropyl linoleate has the highest compound concentration of (21.83%) followed by the Cyclohexanol,5-methyl-2-(1-methyl ethyl) 13.38%, then Octadecenoic acid (E) with concentration of ( 7.75%). The aim of this study compare the phytochemical of different volatile oil extract of O. basilicum L. and M. spicata L.

Direct determination of five xanthic acids in water by ultra performance liquid chromatography-tandem mass spectrometry

Xanthates with different alkyl groups, such as ethyl, propyl, butyl, and amyl groups, are widely used in large quantities in the mining flotation of metallic minerals. Xanthates enter environmental waters through mineral processing wastewater discharge and are ionized or hydrolyzed into ions or molecules of xanthic acids (XAs) in water. XAs endanger aquatic plants and animals, as well as human health. To the best of our knowledge, XA analysis is mainly limited to butyl xanthate. Moreover, the isomers and congeners of XAs cannot be determined separately using the existing methods. Herein, a novel method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established to separate and analyze five XAs, namely, ethyl-, isopropyl-, n-butyl-, isobutyl-, and amyl-XAs, in water. Water samples were filtered through a 0.22 μm hydrophilic polytetrafluoroethylene (PTFE) membrane and directly injected into the UPLC-MS/MS instrument. Separation was performed using a Waters Acquity UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm) with ammonia solution (pH 11)-acetonitrile (9∶1, v/v) as the mobile phase for isocratic elution. The five XAs were detected in the negative electrospray ionization (ESI-) and multiple reaction monitoring (MRM) modes. An internal standard method was used for quantification. The pretreatment and UPLC-MS/MS conditions were comprehensively optimized to achieve the separation and analysis of the five XAs via direct injection. The XAs showed negligible adsorption on hydrophobic PTFE, hydrophilic PTFE, hydrophilic polypropylene, and polypropylene membranes during filtration. However, the amyl-XA showed obvious adsorption on nylon and polyether sulfone membranes. The five XAs mainly formed [M-H]- parent ions in the ESI- mode and the main daughter ions obtained following collisional fragmentation depended on the alkyl groups of the XAs. Increasing the pH of the ammonia solution in the mobile phase to 11 led to the isomeric separation of n-butyl- and isobutyl-XAs. The optimized mobile phase inhibited the tailing of the chromatographic peak of amyl-XA and effectively improved all the chromatographic peak shapes of XAs. The BEH C18 column was selected as the chromatographic column owing to its better compatibility with high-pH solutions compared with the T3 C18 column. Preservation experiments conducted over 8 d showed that the concentration of all five XAs decreased over time at room temperature; among the XAs analyzed, the concentration of ethyl-XA revealed the most significant decrease. However, the recoveries of the five XAs at 4 and -20 ℃ remained high, ranging from 101% to 105% and from 100% to 106%, respectively, on the 8th day. The preservation observed with a high concentration of XAs was similar to that found with a low concentration. The preservation time was extended to 8 days at pH 11 and 4 ℃ away from the light. No significant matrix effects were observed for the five XA samples in surface water and groundwater, but industrial sewage exerted obvious matrix inhibitory effects on ethyl- and isopropyl-XAs. Owing to the short retention times of ethyl- and isopropyl-XAs, the co-fluxed interferents in the industrial sewage depressed the MS signals. The five XAs showed good linearity in the range of 0.25-100 μg/L, with correlation coefficients greater than 0.9996. The method detection limits were as low as 0.03-0.04 μg/L, and the intra- and inter-day precisions were 1.3%-2.1% and 3.3%-4.1%, respectively. The recoveries obtained under low, medium, and high spiked levels (1.00, 20.0, 80.0 μg/L) were 96.9%-133%, 100%-107%, and 104%-112%, respectively. The corresponding RSDs were 2.1%-3.0%, 0.4%-1.9%, and 0.4%-1.6%, respectively. The optimized method was successfully applied to the analysis of XAs in surface water, groundwater, and industrial sewage. The method could separate and detect various congeners and isomers of XAs without the need for cumbersome pretreatment processes, and its advantages include smaller sample requirements, simpler operation, higher sensitivity, and longer preservation time. The proposed technique presents excellent application potential in XA environmental monitoring and water evaluation, and mineral flotation studies.

Syntheses and crystal structure of a (2,6-diiso-propyldi-naphtho-[2,1-d:1',2'-f][1,3]dithiepin-4-yl)(phen-yl)methanol atropisomer.

The racemic title compound, C34H32OS2, comprises an atropisomeric binaphthyl di-thio-acetal substituted at the methyl-ene carbon atom with a chiral benzyl alcohol. The two naphthalene ring systems are additionally substituted at the 3,3'-position with isopropyl groups. The overall stereochemistry is defined as aS,R and aR,S. The hydroxyl group forms an intra-molecular O-H⋯S hydrogen bond to one of the sulfur atoms. The crystal structure contains weak C-H⋯π inter-actions that link the mol-ecules into extended arrays.

Ferruginol and Sugiol: A Short Review of their Chemistry, Sources, Contents, Pharmacological Properties and Patents

In this short article, the chemistry, sources, contents, pharmacological properties and patents of ferruginol (FG) and sugiol (SG) are reviewed for the first time. Sources of information cited on these two abietane diterpenes were from databases such as Google, Google Scholar, PubMed, Science Direct, J-Stage, Web of Science and PubChem. In the selection of articles, recent references were accorded higher priority apart from their relevance to the topics. Both FG and SG are characterized by a tricyclic ring system with a hydroxyl group and an isopropyl group at ring C. SG has a carbonyl group at ring B that is absent in FG. Found in the bark and root of plant species particularly those belonging to the families Cupressaceae and Lamiaceae, FG and SG have attracted much attention because of their diverse pharmacological properties, notably, their anti cancer and anti-protozoal activities. Three patents on FG and one on SG are described. Some areas of research requiring further investigations are suggested.

Linker-length dependent intra/intermolecular coordination of synthetic zinc chlorophyll-a derivatives bearing a pyridine terminal in the C132-substituent

An ω-(m-pyridyl)alkyl group was introduced at the C132-methoxycarbonyl group of methyl pheophorbide-a as a chlorophyll-a derivative by exchange of the esterifying moiety. To avoid allomerization and epimerization of the C132-chiral center in the β-keto-ester moiety, a propyl group was substituted at the C132-position. The free bases were zinc-metalated to give zinc methyl 132-propyl-pheophorbides-a bearing an oligomethylene chain with a pyridyl terminal at the C132-position. Depending on the length of the alkyl chain between the terminal pyridine and C132-carboxylate moieties, the coordination of the m-pyridyl group with the central zinc atom in the stereochemically pure and fixed zinc chlorin–pyridine conjugates occurred in intra- or intermolecular fashions.

Reaction between 1,3,5-Triisopropylbenzene and Elemental Sulfur Extending the Scope of Reagents in Inverse Vulcanization.

Inverse vulcanization utilizes an organic compound as reagent for crosslinking elemental sulfur to result in corresponding polymeric material with a high sulfur content. This work, employing 1,3,5-triisopropylbenzene (TIPB) as the reagent, demonstrates the first attempt on extending the scope of crosslinking agents of inverse vulcanizationtosaturatecompounds. Under nuclearmagneticspectroscopic analysis, the reactions between TIPB and elemental sulfur take places through ring-opening reaction of S8 resulting in sulfur radicals at sulfur chain ends, radicals transferring to isopropyl groups of TIPB, and radical coupling reactions between carbon radicals and sulfur radicals. The obtained products are similar to the sulfur polymers from conventional inverse vulcanization processes and show self-healing property.

Synthetic Cinnamides and Cinnamates: Antimicrobial Activity, Mechanism of Action, and In Silico Study

The severity of infectious diseases associated with the resistance of microorganisms to drugs highlights the importance of investigating bioactive compounds with antimicrobial potential. Therefore, nineteen synthetic cinnamides and cinnamates having a cinnamoyl nucleus were prepared and submitted for the evaluation of antimicrobial activity against pathogenic fungi and bacteria in this study. To determine the minimum inhibitory concentration (MIC) of the compounds, possible mechanisms of antifungal action, and synergistic effects, microdilution testing in broth was used. The structures of the synthesized products were characterized with FTIR spectroscopy, 1 H-NMR, 13 C-NMR, and HRMS. Derivative 6 presented the best antifungal profile, suggesting that the presence of the butyl substituent potentiates its biological response (MIC = 626.62 μM), followed by compound 4 (672.83 μM) and compound 3 (726.36 μM). All three compounds were fungicidal, with MFC/MIC ≤ 4. For mechanism of action, compounds 4 and 6 directly interacted with the ergosterol present in the fungal plasmatic membrane and with the cell wall. Compound 18 presented the best antibacterial profile (MIC = 458.15 μM), followed by compound 9 (550.96 μM) and compound 6 (626.62 μM), which suggested that the presence of an isopropyl group is important for antibacterial activity. The compounds were bactericidal, with MBC/MIC ≤ 4. Association tests were performed using the Checkerboard method to evaluate potential synergistic effects with nystatin (fungi) and amoxicillin (bacteria). Derivatives 6 and 18 presented additive effects. Molecular docking simulations suggested that the most likely targets of compound 6 in C. albicans were caHOS2 and caRPD3, while the most likely target of compound 18 in S. aureus was saFABH. Our results suggest that these compounds could be used as prototypes to obtain new antimicrobial drugs.

Structural and Spectroscopic Studies of Steric and Electronic Substituent Effects in a Series of Magnesium Aminodiboranates Mg[(BH3)2NMeR]2.

The magnesium N,N-dimethylaminodiboranate compound Mg[(BH3)2NMe2]2, the most volatile compound of magnesium known, serves as an excellent chemical vapor deposition (CVD) precursor for the growth of thin films such as the dielectric material MgO. To explore how the thermal stability and physical properties of magnesium aminodiboranates depend on the steric and electronic properties of the nitrogen-bound substituents, we have made a series of analogues of Mg[(BH3)2NMe2]2, in which one of the two methyl substituents on nitrogen is replaced with an ethyl, iso-propyl, or tert-butyl group. In the crystal structure of Mg[(BH3)2NMe(t-Bu)]2, the magnesium center is coordinated to two chelating (BH3)2NMe(t-Bu) ligands, each of which binds in a κ2,κ2 fashion so that the magnesium center forms eight Mg-H contacts. Unlike Mg[(BH3)2NMe2]2, however, which has a linear N···Mg···N angle and is an isolated molecule in the solid state, the N···Mg···N angle in Mg[(BH3)2NMe(t-Bu)]2 is distinctly nonlinear (149.9°) because hydrogen atoms of BH3 groups of nearby molecules form two additional Mg-H contacts with the magnesium center. When the complexes are heated in toluene solution, the (BH3)2NMeR- groups reversibly undergo B-N bond cleavage (with concomitant migration of a hydrogen atom) to release the aminoborane BH2═NMeR and form magnesium borohydride, Mg(BH4)2. For the methyl, ethyl, and iso-propyl derivatives, the equilibrium strongly favors Mg[(BH3)2NMeR]2. In contrast, for the tert-butyl derivative, the equilibrium strongly favors BH2═NMe(t-Bu) and Mg(BH4)2. The results suggest that more strongly electron-donating groups slightly strengthen the B-N bonds and disfavor B-N bond cleavage, provided that the groups are not too large. In contrast, sterically bulky ligands disfavor B-N bond reformation, thus promoting the dissociative equilibrium that involves B-N bond cleavage. Interestingly, the rates at which the complexes approach equilibrium depend only weakly on the nature of the R group, at least within the series studied. These findings are relevant to the potential use of magnesium aminodiboranates as CVD precursors to the superconducting phase MgB2.

Characterization of essential oil compounds on leaves and rhizomes of turmeric (Curcuma domestica Val.)

This study aimed to determine the characterization of essential oils in turmeric leaves and rhizomes using Chromatography-Mass Spectrophotometry (GC-MS). In this study, essential oils were obtained by steam distillation on the leaves and rhizomes of turmeric seven months old in the Panjalu area. Based on the research results, there were eight similar compounds, alpha-phellandrene, 1,3-cyclohexadiene 1-methyl-4-(1-methyl ethyl), P-Cymene, D-Lymonene, Eucalyptol, aR-Tumerone, Tumerone, and Curlone.

Urinary concentration of selected nonpersistent endocrine disrupting chemicals—reproductive outcomes among women from a fertility clinic

Parabens and benzophenones are compounds widely used in cosmetics and personal care products. Although human exposure is widespread there is a limited number of epidemiological studies assessing the relationship between exposure to these chemicals and female reproductive health. The aim of the study is to explore the relationship between paraben and benzophenone concentrations and reproductive outcomes among women attending a fertility center. This prospective cohort included 450 women undergoing in vitro treatment (IVF) at fertility clinic in Poland. The validated gas chromatography ion-tap mass spectrometry to assess concentrations of parabens in urine (methyl (MP), ethyl (EP), propyl (PP), butyl paraben (BP)) and benzophenone-3 (BP-3) was used. To explore the relationship between concentrations of examined chemicals and reproductive outcomes (methaphase II (MII) oocyte yield, total oocyte yield, implantation rate, fertilization rate, clinical pregnancy, live births), multivariable generalized linear mixed model was used for the analysis. Increased exposure to butyl paraben was associated with a significant decrease in MII oocyte count (p = 0.007) when exposure to BP was treated as the continuous variable. Additionally, the exposure to BP in the highest quartile of exposure also decreases MII oocyte count (p = 0.02) compared to the lowest quartile. Urinary concentrations of BP were not related to total oocyte count, fertilization and implantation rate, clinical pregnancy, and live birth when the exposure variable was continuous variable or in the quartiles of exposure. Exposure to MP, EP, PP, the sum of examined parabens, and benzophenone-3 were not related to any of the examined reproductive outcomes. Exposure to butyl paraben was associated with a decrease in MII oocyte count among women attending fertility clinic rinsing concerns that exposure may have a potential adverse impact on embryological outcomes. The results emphasize the importance to reduce chemicals in the environment in order to minimize exposure. As this is the first study showing such an association, further research is needed to confirm these novel results in other populations.Graphical