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The present study corroborates that the neutral tridentate N‐ligand 1,4,7‐trimethyl‐triazacyclononane (Me3TACN) qualifies as a versatile platform to study selective ligand exchange with rare‐earth‐metal alkyl complexes, herein [(Me3TACN)YMe3]. Treatment with Brønsted‐acidic bis(dimethylsilyl)amine, HN(SiHMe2)2, gave selectively the mono‐exchanged heteroleptic complex [(Me3TACN)YMe2{N(SiHMe2)2}]. Depending on the molecular ratio employed, the reaction of [(Me3TACN)YMe3] with AlMe3 resulted in the isolation/crystallization of [(Me3TACN)YMe2(AlMe4)] [1 : 1] or ion‐separated [(Me3TACN)YMe(AlMe4)][AlMe4] [1 : 2] and [(Me3TACN)YMe(AlMe4)][Al2Me7] [1 : 3]. Analogous reactions with the heavier group 13 methyls GaMe3 and InMe3 generated mixed methyl/tetramethylgallato complex [(Me3TACN)YMe2(GaMe4)] and ion‐separated [{(Me3TACN)YMe2}2{μ‐Me}][InMe4]. Finally, dimethylalane, HAlMe2, converted [(Me3TACN)YMe3] into heteroaluminate [(Me3TACN)Y(HAlMe3)3], representing an AlMe3‐supported, molecular yttrium trihydride complex. All compounds were investigated by single crystal X‐ray diffraction (SC‐XRD), homo‐ and heteronuclear (13C, 27Al, 89Y, 115In) NMR as well as IR spectroscopies and elemental analyses. [ABSTRACT FROM AUTHOR]

A quantum chemical study of the rates of chemical reactions of formation of silaethylene and the methyl and silyl radicals by the pyrolysis of methylsilane in the gas phase was performed. The geometry and thermodynamic characteristics of the compounds participating in the chemical reactions were calculated by an ab initio method according to the second-order Møller–Plesset perturbation theory with the 6–31+G basis set at temperatures up to 2700 K. The equilibrium constants and rates of the studied reactions were calculated, and so were the pre-exponential factor and activation energy for the Arrhenius equation. [ABSTRACT FROM AUTHOR]

Objective: Methyl alcohol, which is quite cheap compared to ethyl alcohol, can be used to produce imitated alcohol. For this reason, cases of methyl alcohol intoxication can be observed from time to time. Although it is rare, it is an emergency that needs to be diagnosed and treated early because of its high mortality. Methods: In this study, 22 patients aged ≥18 years who were admitted to the intensive care unit (ICU) due to methyl alcohol intoxication between 2015 and 2022 were included. The patients were divided into 2 groups, survivor and non-survivor, and compared retrospectively in terms of factors predicting mortality. Results: Except for one of the 22 patients included in the study, all patients developed methyl alcohol intoxication because of the use of imitated alcohol. Only one patient had a history of using perfume for suicidal purposes. Of the patients who developed methyl alcohol intoxication, 13 (59%) were in the non-survivor group and 9 (41%) were in the survivor group. While the rate of invasive mechanical ventilation needed before the ICU was 55.6% in the survivor group, it was 100% in the non-survivor group, and there was a statistically significant difference between them (p<0.017). In the non-survivor patient group, blood HCO3 and pH levels were found to be significantly lower after ICU admission (p=0.002, p=0.008). At the same time, blood creatinine, potassium, and total bilirubin levels were significantly higher (p=0.002, p=0.007, p<0.035). Acute physiology and chronic health evaluation-II and sequential organ failure assessment scores after ICU admission were also significantly higher in the non-survivor group than in the survivor group (p=0.005, p=0.035). Conclusion: It was determined that in patients who died due to methyl alcohol intoxication, deeper metabolic acidosis and irreversible multiorgan failure developed during the period until ICU admission. The acute physiology and chronic health evaluation-II and sequential organ failure assessment scores were both effective in predicting mortality. [ABSTRACT FROM AUTHOR]

In this work, a series of semi‐crystalline semi‐aromatic poly (ether amides) (PAT‐2–PAT‐10) with varying length of polymethylene moiety (2, 4, 6, 8 or 10 methyl groups) and number of ether groups in the main chain were synthesized by the nucleophilic substitution reaction of semi‐aromatic difluorobenzamido alkanes with 1, 4‐benzenediol at about 190–200°C, using K2CO3 as catalyst, N‐methyl pyrrolidione (NMP) as reaction solvent. And their viscosities, thermal, and mechanical properties were investigated. The inherent viscosities, glass transition, melting and degradation temperatures and tensile strength values of the synthesized polymers were in the range 0.141–1.829 dL g−1, 119.1–165.0°C, 272.4–345.4°C, and 371.4–451.1°C, and 61.2–79.2 MPa respectively. Moreover, they were found to have good solubility in concentrated sulfuric acid and trifluoroacetic acid at room temperature. The length of poly methylene group and ether bond in the polymer main chain had significantly influenced their thermo mechanical properties. The polyamides PAT‐6–PAT‐10 had better thermo mechanical property than that of commercial polyamide, PA6T/66. [ABSTRACT FROM AUTHOR]

The synthesis of the new energetic material 4-amino-3-hydrazino-5-methyl-1,2,4-triazole, which shows excellent performance and reliable safety, has drawn attention recently. To fully characterize this material, a comprehensive analysis was performed using various techniques, including differential scanning calorimetry (DSC), infrared spectroscopy (IR), elemental analysis, and 1H and 13C NMR spectroscopy. Additionally, three compounds, 3, 5 and 9, were further characterized using single X-ray diffraction. The X-ray data suggested that extensive hydrogen bonds affect molecular structure by means of intermolecular interactions. In order to evaluate the explosive properties of these synthesized compounds, detonation pressures and velocities were calculated using EXPLO5 (V6.01). These calculations were carried out utilizing experimental data, including density and heat of formation. Among the explosives tested, compounds 7 and 8 exhibited zero oxygen balance and demonstrated exceptional detonation properties. Compound 7 achieved the highest recorded detonation pressure, at 34.2 GPa, while compound 8 displayed the highest detonation velocity, at 8887 m s−1. [ABSTRACT FROM AUTHOR]

One of the key scientific aspects of small-molecule drug discovery and development is the analysis of the relationship between its chemical structure and biological activity. Understanding the effects that lead to significant changes in biological activity is of paramount importance for the rational design and optimization of bioactive molecules. The "methylation effect", or the "magic methyl" effect, is a factor that stands out due to the number of examples that demonstrate profound changes in either pharmacodynamic or pharmacokinetic properties. In many cases, this has been carried out rationally, but in others it has been the product of serendipitous observations. This paper summarizes recent examples that provide an overview of the current state of the art and contribute to a better understanding of the methylation effect in bioactive small-molecule drug candidates. [ABSTRACT FROM AUTHOR]

Cytochrome c (cyt c) is an important multifunctional protein. In mitochondria, it acts as a carrier for electron transporting. In cytoplasm, it may act as an apoptotic initiator to initiate the apoptotic process. Whether and how a complex cytoplasmic environment affects its conformation has not been confirmed yet. In this study, the conformational changes of wild type saccharomyces cerevisiae iso-1 cyt c in yeast cell homogenate were tracked by methyl-based nuclear magnetic resonance (NMR) technique. At least four different oxidative conformations and one reduced conformation of cyt c were identified in cell homogenate. And over time, the transitions among different conformations of cyt c were observed. The results indicate that the conformation of cyt c changes with environment, which may be closely related to resistance to oxidative stress.

Kommerziell erhältliche Stammlösungen von Organolithiumverbindungen sind vielfach eingesetzte Reagenzien in der Organischen und Metallorganischen Chemie. Solche Lösungen sind jedoch von "Natur aus" mit Lithiumhalogenidsalzen verunreinigt, die viele Syntheseprotokolle und Aufreinigungsprozesse erheblich einschränken. In dieser Arbeit beschreiben wir die Isolierung von chloridfreiem Methyllithium mithilfe von K[N(SiMe3)2] als Halogenidfällungsreagenz. Der Einfluss von definierten LiCl‐Verunreinigungen auf die 7Li‐NMR chemische Verschiebung wurde systematisch untersucht und quantifiziert. Die strukturellen Parameter des neuen chloridfreien Methyllithiumkomplexes [(Me3TACN)LiCH3] wurden mit der halogenidverunreinigten Variante und monomerem Lithiumchlorid [(Me3TACN)LiCl] verglichen. [ABSTRACT FROM AUTHOR]

Commercially available stock solutions of organolithium reagents are well‐implemented tools in organic and organometallic chemistry. However, such solutions are inherently contaminated with lithium halide salts, which can complicate certain synthesis protocols and purification processes. Here, we report the isolation of chloride‐free methyllithium employing K[N(SiMe3)2] as a halide‐trapping reagent. The influence of distinct LiCl contaminations on the 7Li‐NMR chemical shift is examined and their quantification demonstrated. The structural parameters of new chloride‐free monomeric methyllithium complex [(Me3TACN)LiCH3], ligated by an azacrown ether, are assessed by comparison with a halide‐contaminated variant and monomeric lithium chloride [(Me3TACN)LiCl], further emphasizing the effect of halide impurities. [ABSTRACT FROM AUTHOR]

The objective of this study is to explore conditions that facilitate a significant reduction in substrate temperature during diamond growth. The typical temperature for this process is around 1200 K; we aim to reduce it to a much lower level. To achieve this, we need to understand processes that limit the diamond growth at low temperatures. Therefore, we developed a detailed chemical kinetic model to analyze diamond growth on the (100) surface. This model accounts for variations in substrate temperature and gas composition. Using an ab initio quantum chemistry, we calculated the reaction rates of all major gas phase reactants with the diamond surface, totaling 91 elemental surface reactions. Based on this comprehensive model, we developed a reduced model consisting of 8 reactions. This reduction enabled us to derive an analytical equation that describes the rate of diamond growth across a broad range of temperatures involving CH 3 , H, H 2 , and C 2 H 2 reactants. Consistent with previous studies, the model identifies that CH 3 is a major precursor of diamond growth, and the contribution from C 2 H 2 to the growth is significantly smaller. However, C 2 H 2 can also contribute to forming a sp2-phase instead of a sp3-phase, and this process becomes dominant below a critical temperature. As a result, C 2 H 2 flux inhibits diamond growth at low temperatures. To quantify this deleterious process, we developed a new mechanism for sp2-phase nucleation on the (100) surface. Similar to the so-called HACA mechanism for soot formation it involves hydrogen abstraction and C 2 H 2 addition. Consequently, optimal low-temperature CVD growth could be realized in a reactor designed to maximize the CH 3 radical production, while minimizing the generation of C 2 H 2 and other sp. and sp2 hydrocarbons. [Display omitted] [ABSTRACT FROM AUTHOR]

This study highlights the challenges and opportunities of Hydrothermal Liquefaction (HTL) of Cladophora glomerata. It suggests functionalized graphene oxide/polyurethane (F-GO-PU) composite as the promising metal-free catalysts for sustainable algae upgrading. The catalysts contained three types of functional groups, including methyl (-CH 3), vinyl (-CH=CH 2), and amine (-NH 2), and were completely analyzed by FTIR, XRD, and SEM-EDS in terms of functional groups, crystalline structure, morphology, and surface elemental distribution, respectively. The results showed that F-GO-PU catalysts efficiently suppressed side reactions that would generate non-desired chemicals. Functionalization with vinyl increased the yield of bio-crude oil by about 54% and showed high selectivity for hydrocarbons with a yield of 15.66 wt%. This catalytic activity was due to the existence of stable and accessible Brønsted acid sites plus the hybrid structure of the composite, which enhanced the accommodation of reaction intermediates on the surface of the catalyst. Thus, as-prepared F-GO-PU composites may hold great promise as metal-free active phase catalysts to develop algae transformation reactions. [Display omitted] • Multi-functional catalytic system based on graphene and polyurethane. • Effect of functional groups on the green algae bio-products. • Challenges and opportunities of Hydrothermal Liquefaction (HTL) of Cladophora glomerata. • Functionalization with vinyl increased the yield of bio-crude oil by about 54%. [ABSTRACT FROM AUTHOR]

Ficus elastica is a species of the plant in the genus Ficus, from the family Moraceae. Ficus elastica, which is the object of our study, has been used for many years in phytodesign, however in terms of medicine, it remains a poorly studied plant. While studying the external signs and chemical composition of medicinal plant raw materials of leaves Fícus elastica, chromato-mass spectrometry was used. During the process of studying, some diagnostic signs of Ficus elastica were identified. Chromato-mass spectrometry was used to identify 68 compounds. The maximum amount was accounted for б-D-Glucopyranoside, methyl (28,99%), Phytol (9,90%), 2-Hydroxy-3-methylsuccinic acid (6,93%), Lanosterol (6,13%), Hydroquinone (5,55%), 9,12,15-Octadecatrienoic acid, ethyl ester, (Z,Z,Z)- (4,86%), Lup-20(29)-en-3- one (4,17%), 1,2-Benzenediol (3,33%), Lupeol (2,95%), 16-Allopregnene-3б,9а-diol-20-one 3-O-acetate (2,77%), 9-Octadecenamide, (Z)- (2,67%), 9,12,15-Octadecatrienoic acid, (Z,Z,Z)- (2,05%), з-Sitosterol (1,84%), а-d-Lyxofuranoside, methyl (1,57%), Dasycarpidan-1-methanol, acetate (ester) (1,52%), n-Hexadecanoic acid (1,45%), Hexadecanoic acid, ethyl ester (1,33%), 1,8-Dioxacyclohexadecane-2,10- dione, 5,6:12,13-diepoxy-8,16-dimethyl- (1,15%), Vitamin E (0,64%). Identified morphological features of the leaves of Ficus elastica can be used in diagnosis of this species and may help to develop indicators of authenticity for promising medicinal leaves. As mentioned earlier, by means of chromato-mass spectrometry were identified 68 compounds, and the relative percentage of identified compounds was determined using a simple normalization method. [ABSTRACT FROM AUTHOR]

The molecular structure of enigmatic "poly(aluminium‐methyl‐methylene)" (first reported in 1968) has been unraveled in a transmetalation reaction with gallium methylene [Ga8(CH2)12] and AlMe3. The existence of cage‐like methylaluminomethylene moieties was initially suggested by the reaction of rare‐earth‐metallocene complex [Cp*2Lu{(μ‐Me)2AlMe2}] with excess AlMe3 affording the deca‐aluminium cluster [Cp*4Lu2(μ3‐CH2)12Al10(CH3)8] in low yield (Cp*=C5Me5). Treatment of [Ga8(CH2)12] with excess AlMe3 reproducibly gave the crystalline dodeca‐aluminium complex [(CH3)12Al12(μ3‐CH2)12] (MAM‐12). Revisiting a previous approach to "poly(aluminium‐methyl‐methylene" by using a (C5H5)2TiCl2/AlMe3 (1 : 100) mixture led to amorphous solids displaying solubility behavior and spectroscopic features similar to those of crystalline MAM‐12. The gallium methylene‐derived MAM‐12 was used as an efficient methylene transfer reagent for ketones. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel grafted silica nanoparticles were prepared. • Novel green chemical mechanical polishing was developed. • A simple slurry was proposed, including only grafted silica and sodium carbonate. • Atomic surface is achieved on silicon surface. Atomic surface of silicon (Si) wafers is highly desired for integrated circuit (IC) industry. To meet this demand, traditional chemical mechanical polishing usually employs noxious slurries with complex compositions, containing oxidant, dispersant, inhibitor, surfactant, etc., resulting in the pollution of the environment and high-cost post-treatments. To settle this challenge, a novel green chemical mechanical polishing was developed, only including grafted silica nanoparticles and sodium carbonate. After CMP, surface roughness Sa of 0.219 and 0.247 nm are achieved on Si wafers using amine and methyl modified nanoparticles, respectively, corresponding to material removal rate (MRR) of 132.53 and 84.82 nm/min. Amino-modified nanoparticles increase 18.2 % MRR, and methyl modified ones reduce 24.4 % MRR, compared with those of unmodified nanoparticles. X-ray photoelectron spectroscopy reveals that amino-grafted nanoparticles have strong improvement for chemical reactions during CMP. Density functional theory calculations garner the electrostatic potential energy of 4.884 and 6.753 eV for amine and methyl-modified nanoparticles, respectively, corresponding to high and low effects for MRR. This work provides a new avenue to develop novel green simple CMP for Si wafers, reducing the pollution and cost for post-treatments. [ABSTRACT FROM AUTHOR]

Chain dimensions, intermolecular structure and hydration of a series of uncharged and cationic poly(vinyl amine) [PVAm] linear polymers having hydrophobic substituent methyl, n-propyl, and isopropyl in the monomer are studied in aqueous solution by molecular dynamics simulations. A conformational transition occurs in the degree of ionization, α, range 0.3 to 0.4. Among the polymers studied, isopropyl substituted PVAm is most hydrophobic and methyl substituted PVAm is the least. The extent of hydrophobicity of the chemical structure is directly correlated to the size of the polymer chain. Conformational dynamics become slower with increase in the degree of charge of the chain and with the size of the substituent side group. The significant hydration of the polymers takes place for 0 ≤ α ≤ 0.5. While the number of H-bonds is not affected significantly by the chemical structure of the chain the relaxation dynamics of polymer-water H-bonds is significantly affected, with the more hydrophobic polymer showing the slowest dynamics. The steric hindrance provided by the hydrophobic substituent groups is responsible for slowing of water orientation dynamics in the vicinity of the polymer. The counter-ion condensation is clearly better and the bound water content is less for the relatively more hydrophobic polymer. The overall behavior of structure and dynamics is in qualitative agreement with that known for other types of polyelectrolytes and solutes in aqueous solution. [ABSTRACT FROM AUTHOR]

Vibrational spectra of the methyl groups in CH3SH, CH3SCH3, CH3OH, and CH3OCH3 monomers were measured to analyze their complex features as a result of bend/umbrella‐stretch Fermi resonance. Multiple bands were recorded between 2800–3000 cm−1 associated with the vibrations of the methyl groups in CH3OH, and CH3OCH3. On the other hand, the corresponding spectra of CH3SH and CH3SCH3 are relatively simpler with main peaks between 2900 to 3000 cm−1. Theoretical ab initio anharmonic algorithm using six normal modes on a methyl group with potential energy surface at CCSD(T)‐F12/aug‐cc‐pVTZ quality is able to account for all the experimentally observed features across these four species. In CH3SCH3 and CH3SH, all three CH stretch fundamentals are above 2900 cm−1, but the fundamental of umbrella mode is lower than 1350 cm−1, thus only the overtone states of two bending modes are able to borrow sufficient intensities. In CH3OCH3 and CH3OH, umbrella modes have frequencies similar to the bending modes and the CH stretch fundamentals are red‐shifted to 2850–2950 cm−1 leading to more complex vibrational features due to better energy‐matching condition. [ABSTRACT FROM AUTHOR]

Prefoldin is a heterohexameric protein assembly which acts as a co-chaperonin for the well conserved Hsp60 chaperonin, present in archaebacteria and the eukaryotic cell cytosol. Prefoldin is a holdase, capturing client proteins and subsequently transferring them to the Hsp60 chamber for refolding. The chaperonin family is implicated in the early stages of protein folding and plays an important role in proteostasis in the cytosol. Here, we report the assignment of 1HN, 15N, 13C′, 13Cα, 13Cβ, 1Hmethyl, and 13Cmethyl chemical shifts of the 87 kDa prefoldin from the hyperthermophilic archaeon Pyrococcus horikoshii, consisting of two α and four β subunits. 100% of the [13C, 1H]-resonances of Aβ, Iδ1, Iδ2, Tγ2, Vγ2 methyl groups were successfully assigned for both subunits. For the β subunit, showing partial peak doubling, 80% of the backbone resonances were assigned. In the α subunit, large stretches of backbone resonances were not detectable due to slow (μs-ms) time scale dynamics. This conformational exchange limited the backbone sequential assignment of the α subunit to 57% of residues, which corresponds to 84% of visible NMR signals. [ABSTRACT FROM AUTHOR]

Methyl radicals play key roles in various chemical and biological processes. Mechanistic studies of methyl radicals with their precursor, Dimethyl Sulfoxide (DMSO), were extensively studied. Though the involved mechanisms seemed to be clarified, essentially none of the studies have been performed at conditions relevant to both biological and catalytic systems, i.e. low steady state radical concentrations. A chain-like reaction, as an inverse function of the radicals concentrations ([•CH 3 ] ss), increases the methyl radical yields. The nature of the additional products obtained differs from those commonly observed. Furthermore it is shown that methyl radicals abstract a methyl group from DMSO to yield ethane. Herein we report a novel mechanism relevant mainly at low steady state radical concentrations, which may change the understanding of certain reaction routes present in both biological systems and catalytic chemical systems. Thus the results point out that mechanistic studies have to be carried out at dose rates forming radicals at analogous concentrations to those present in the process of interest. Image 1 • Low steady state concentrations of radicals alter the reaction mechanism. • Several new reaction paths, that produce new radicals, have been identified. • Processes in living systems might differ from those observed in model studies. [ABSTRACT FROM AUTHOR]

Methyl groups are valuable probes for solution NMR, allowing the investigation of large protein complexes. Among the six methyl containing residues, threonine has one of the less hydrophobic side chain, and can reside both within the interior of a protein or on the protein surface. This article presents an efficient mixed chemical/enzymatic synthesis scheme, enabling the preparation of threonine with natural configuration on the two stereogenic centers together with an optimal introduction of 1H/2H and 12C/13C atoms at specific sites. Such specifically labelled amino acid can be efficiently incorporated in overexpressed proteins without scrambling or in combination with any other types of 13CH3 probes. Additionally we report application to the 82 kDa Malate Synthase G. Our findings demonstrate that structural meaningful long range nOes can be detected between threonine methyl probes and methionine and isoleucine methyl groups distant by 12 Å. [ABSTRACT FROM AUTHOR]

Conformational change of cytochrome c (cyt c) caused by interaction with cardiolipin (CL) is an important step during apoptosis, but the underlying mechanism is controversial. To comprehensively clarify the structural transformations of cyt c upon interaction with CL and avoid the unpredictable alias that might come from protein labeling or mutations, the conformation of purified yeast iso–1 cyt c with natural isotopic abundance in different contents of CL was measured by using NMR spectroscopy, in which the trimethylated group of the protein was used as a natural probe. The data demonstrate that cyt c has two partially unfolded conformations when interacted with CL: one with Fe–His33 coordination and the other with a penta–coordination heme. The Fe–His33 coordination conformation can be converted into a penta–coordination heme conformation in high content of CL. The structure of cyt c becomes partially unfolded with more exposed heme upon interaction with CL, suggesting that cyt c prefers a high peroxidase activity state in the mitochondria, which, in turn, makes CL easy to be oxidized, and causes the release of cyt c into the cytoplasm as a trigger in apoptosis.

In the title compound, C11H10N2OS, the dihedral angle between the thiophene and pyridine rings is 77.79 (8)°. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generate R22(10) loops. The dimers are reinforced by pairs of C—H...N interactions and C—H...O interactions link the dimers into [010] chains.

The aim of this paper was to study the response of methyl (CH3) and methylene (CH2) vibration bands in amino acids of some typical proteins diluted in bidistilled water solution after exposure to a high-frequency electromagnetic fields using Fourier Transform Infrared (FTIR) Spectroscopy. Hemoglobin in H2O solution and bovine serum albumin and myoglobin diluted in different D2O solutions were exposed for 4 h to a power density of 0.95 W/m2 at the frequency of 1750 MHz, emitted by operational mobile phones Nokia model 105 and Samsung model GT-E1270, in order to study the response of stretching vibrations of CH3 and CH2 that are in amino acids of those proteins. The main result was that CH3 stretching bands increased significantly in myoglobin in D2O solution because this protein is represented by a single protein chain so that the torque induced by the applied field is larger than that induced on the other two proteins. Otherwise, CH2 stretching vibrations decreased in intensity significantly for all exposed proteins. This result can be explained as well, assuming that, given a fixed volume, a decrease of population of CH2 occurred after exposure because of the alignment of proteins α-helices along the direction of the applied electromagnetic field. [ABSTRACT FROM AUTHOR]

We used the DACAPO code with the GGA-PW91 approximation to study the adsorption of methyl (CH3) and hydroxyl (OH) for four- and five-layer gold (Au) (001) slabs. We have determined for each species the best binding site, adsorption energy, the change in the work function, surface energy, surface dipole moment, geometrical parameters and projected density of states (PDOS). We performed spin-unpolarized and spin-polarized DFT calculations for free and adsorbed CH3 and OH species. The most important point is that the spin polarization diminishes the adsorption energies but does not change the geometrical parameters. For the CH3 species, only the top site was found to be stable for different coverages. We found that during the optimization phase, the hollow and bridge sites were found to be unstable. In both cases the CH3 species moves toward the top site. We observe that the adsorption energy decreases when increasing the coverage. However, the OH species was stable in all investigated sites (top, bridge and hollow). We notice that the adsorption energy is dependent on the number of slab layers and the bridge is the best site in adsorption energy. The analysis of the calculated O PDOS of OH radical shows a mixing between the O orbitals and the Au bands. [ABSTRACT FROM AUTHOR]

The syntheses and characterizations of the chelating ligand 6-chloro-6′-methyl-2,2′-bipyridine (6-Cl-6′-Mebpy) and of the copper(I) compounds [Cu(POP)(6-Cl-6′-Mebpy)][PF6] and [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6] (POP = bis(2-(diphenylphosphanyl)phenyl)ether and xantphos = 4,5-bis(diphenylphosphanyl)-9,9-dimethyl-9H-xanthene) are described. The single crystal structures of both complexes were determined; the copper(I) ion is in a distorted tetrahedral environment and in [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6], the disorder of the 6-Cl-6′-Mebpy ligand indicates there is no preference of the ‘bowl’-like cavity of the xanthene unit to host either the methyl or chloro-substituent, consistent with comparable steric effects of the two groups. The electrochemical and photophysical properties of [Cu(POP)(6-Cl-6′-Mebpy)][PF6] and [Cu(xantphos)(6-Cl-6′-Mebpy)][PF6] were investigated and are compared with those of the related compounds containing 6,6′-dichloro-2,2′-bipyridine or 6,6′-dimethyl-2,2′-bipyridine ligands. Trends in properties of the [Cu(P^P)(N^N)]+ complexes were consistent with 6-Cl-6′-Mebpy behaving as a combination of the two parent ligands.

Goat meat is considered healthy because it has fewer calories and fat than meat from other traditional meat species. It is also rich in branched chain fatty acids that have health advantages when consumed. We studied the effects of maternal milk and milk replacers fed to suckling kids of four breeds on the straight and branched fatty acid compositions of their muscle. In addition, the proximal and fatty acid compositions of colostrum and milk were studied. Goat colostrum had more protein and fat and less lactose than milk. Goat milk is an important source of healthy fatty acids such as C18:1 c9 and C18:2 n–6. Suckling kid meat was also an important source of C18:1c9. Dairy goat breeds had higher percentages of trans monounsaturated fatty acids (MUFAs) and most of the C18:1 isomers but lower amounts of total MUFAs than meat breeds. However, these dairy kids had meat with a lower percentage of conjugated linoleic acid (CLA) than meat kids. The meat of kids fed natural milk had higher amounts of CLA and branched chain fatty acids (BCFAs) and lower amounts of n–6 fatty acids than kids fed milk replacers. Both milk and meat are a source of linoleic, α-linolenic, docosahexaenoic, eicosapentaenoic and arachidonic fatty acids, which are essential fatty acids and healthy long-chain fatty acids.

Graphical abstract Abstract In order to expand the application of lignin, magnetic lignin-based carbon nanoparticles (MLBCN) were synthesized using a precipitation-carbonization process and the structure was confirmed by FTIR, XRD, Raman, BET, SEM, DLS and VSM. The adsorption of MLBCN for methyl orange was consistent with the Langmuir model and pseudo-second-order model, showing monolayer adsorption, with a maximum adsorption capacity of 113.0 mg/g and chemisorption being the rate-controlling step. This process was exothermic and of entropy reduction, showing spontaneous below 35 °C. MLBCN could be used under near neutral conditions and easily regenerated. This study demonstrates that MLBCN is promising as an efficient, sustainable absorbent. [ABSTRACT FROM AUTHOR]

In several instances, methyl group was found to play a pivotal role when present in a molecule. Its hydrophobic character has been the key success factor for specific performances when lipophilicity is the basic requirement for a phenomenon to occur. In some cases, chemical reactivity and physical phenomena are specifically linked to the effects of methyl group. [ABSTRACT FROM AUTHOR]

Crystal structures of 4-chloro-N-(4-chlorobenzoyl)-N-(2-pyridyl)benzamide (I) Clpod, 3-chloro-N-(3-chlorobenzoyl)-N-(2-pyridyl)benzamide (II) Clmod and 2-chloro-N-(2-chlorobenzoyl)-N-(2-pyridyl)benzamide (III) Clood together with three methylated analogues, Mpod, Mmod and Mood, are presented herein. The Clxod acyclic imides are produced from reacting the 4-/3-/2-chlorobenzoyl chlorides (Clx) with 2-aminopyridine (o), respectively, together with their benzamide analogues Clxo; the Mxod/Mxo triad are produced similarly and in good yield. The five Clxod, Mpod and Mmod structures adopt the open transoid conformations as expected, but Mood crystallises with cisoid oriented benzoyl groups, and this conformation was unexpected, though not unknown. Halogen bonding contacts and weak hydrogen bonding C-H···N/O/π contacts are noted in the structures lacking strong hydrogen bonding donor atoms/groups but possessing a variety of strong and weaker acceptor atoms/groups. For Clxod, contact studies show that both hydrogen and carbon account for a high percentage of elements (70-75%) on the molecular surface and being the most abundant have C···H forming 26-30% of the contacts. Contact enrichment ratios are an indicator of the likelihood of chemical species to form intermolecular interactions with themselves and other species. The C-H···N and C-H···O are the most enriched (with EHN > 2.15), indicating that these weak hydrogen bonds are the driving force in the Clxod crystal packing formation. For Mxod, the C···H contact type at 40-52% is the most abundant contact type and C-H···O and C-H···N weak hydrogen bonds dominate with enrichment values in the 1.48-1.78 range. In Mxod, N/O···N/O contacts are effectively absent, except for Mpod (0.2%, N···N contacts) and both H···H and C···C non-polar contacts are moderately impoverished while the C···H interactions are slightly enriched (E = 1.1-1.21). [ABSTRACT FROM AUTHOR]

Background: Propofol is the most widely used intravenous anesthetic agent for induction and maintenance of anesthesia as well as for sedation inside and outside operation theatre. Propofol is almost an ideal intravenous (IV) anesthetic agent, but pain on its injection still remain a problem. Pain may not be a serious complication, but most patients remember it as one of the unpleasant encounters with anesthetists. In one survey pain on propofol injection stands seventh most important problem in the current practice of clinical anesthesia. Ketamine is (NMDA) receptor antagonist agent and a dissociative anesthetic with neurostimulatory side effect, multiple research trials suggest ketamine as a strong analgesic agent in sub anesthetic IV doses. Objective: The aim of the current study was to prove the effectiveness of low dose ketamine in preventing propofol injection pain. Methodology: Two groups each included 60 patients (middle age females who performed ovum pick up surgery: Ketamine group 60 patient received ketamine 0.2 mg/kg with propofol. Saline group 60 patient received normal saline 10 ml with propofol. Results: In the current study pain and hemodynamic changes (BP, pulse) were observed. Regarding pain: The incidence of propofol injection pain in the current study was reduced from 93.2% in saline group to 55% in ketamine group, the incidence of severe pain was completely abolished with ketamine. Regarding hemodynamics: There was no statistical significance between both groups regarding heart rate, regarding BP the degree of drop in BP in ketamine group was to less extent than in saline group that proves the role of ketamine in hemodynamic stability. Conclusion: Finally ketamine in low dose was effective in reduction of propofol injection pain. [ABSTRACT FROM AUTHOR]

Melting point is an important index to determine whether an explosive can be a melt cast carrier. In this study, the relationship among the molecular structure, crystal structure, and melting point of explosives was investigated by using nitroazole compounds. Hydrogen bonds influence crystal packing modes in chemically understandable ways. Hydrogen bonds also affect the changes in entropy and enthalpy in balancing melting process. Hence, different types of hydrogen bonds in explosive crystal structures were compared when the relationship between the molecular structure and the melting point of nitroazole explosives were analyzed. The effects of methyl and amino groups on intermolecular hydrogen bonds were also compared. Results revealed that the methyl and amino groups connected on the N(1) of the heterocyclic compound can reduce the melting point of azole explosive. This finding is possible because methyl and amino groups destroy the intermolecular hydrogen bond of the heterocyclic compound. [ABSTRACT FROM AUTHOR]

Quantum‐rotor‐induced polarization is closely related to para‐hydrogen‐induced polarization. In both cases, the hyperpolarized spin order derives from rotational interaction and the Pauli principle by which the symmetry of the rotational ground state dictates the symmetry of the associated nuclear spin state. In quantum‐rotor‐induced polarization, there may be several spin states associated with the rotational ground state, and the hyperpolarization is typically generated by hetero‐nuclear cross‐relaxation. This review discusses preconditions for quantum‐rotor‐induced polarization for both the 1‐dimensional methyl rotor and the asymmetric rotor H217O@C60, that is, a single water molecule encapsulated in fullerene C60. Experimental results are presented for both rotors. [ABSTRACT FROM AUTHOR]

Background Folate is required for synthesis of methyl groups and DNA in growing cells. The association between folate and prostate cancer (PCa) is not conclusive. Methods We investigated concentrations of folate vitamers, S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM) in blood of men with PCa (n = 129) or benign prostatic hyperplasia (BPH) (n = 73) who were recruited just after the first diagnosis. Results In younger subjects <65 years, concentrations of (6S)-5-CH 3 -H 4 folate (15.3 vs. 17.7 nmol/L) or total folate (UPLC-MS/MS) (18.7 vs. 23.0 nmol/L) did not differ between men with BPH and those with PCa, while SAM was higher in the controls (128 vs. 116 nmol/L). Younger patients with low- and high grade cancer did not differ in (6S)-5-CH 3 -H 4 folate (17.8 vs. 17.3 nmol/L) or total folate (UPLC-MS/MS) (22.9 vs. 23.3 nmol/L), but SAM was lower in patients with low grade PCa (111 vs. 126 nmol/L). In the older group ≥65 years, (6S)-5-CH 3 -H 4 folate (18.4 vs. 18.2 nmol/L) and total folate (UPLC-MS/MS) (22.5 vs. 22.1 nmol/L) did not differ between BPH and PCa. Older patients with advanced tumors had lower (6S)-5-CH 3 -H 4 folate compared with those with low grade tumor (12.8 vs. 20.0 nmol/L: p = 0.013). Plasma SAM was not different between older patients and controls and was not related to PCa grade. Conclusions Lowered serum methyl folate measured at the time of diagnosis in older patients with advanced PCa, and lowered plasma SAM in younger patients with low grade PCa suggest differential folate metabolism that may have mechanistic, prognostic or predictive values. [ABSTRACT FROM AUTHOR]

Density Functional Theory (DFT) has been employed to investigate the self association of butyronitrile and the heterointeractions in the 1:2 (toluene: butyronitrile) and 1:1 complexes of toluene with butyronitrile. For this investigation the B3LYP functional with Grimme's dispersion correction (D3) term and ωB97XD functionals were used. The theoretical frequency analysis shows the unsuitability of B3LYP with D3 for the present investigation. Therefore, Natural Bonding Orbital analysis was done at the functional ωB97XD. It is found through this work that only the methylene hydrogens of butyronitrile are responsible for the self association among the butyronitrile molecules. In 1:1 complex, the red shift in the butyronitrile methyl asymmetric stretching mode is not due to the active participation of this group in heterointeractions and it is solely due to the other interactions happening in its vicinity. Only the interaction ( T O L ) C − H ⋯ N ( B N ) is present in the complex. In 1:2 complex the butyronitrile methyl/methylene hydrogens interact with the delocalized electron cloud of toluene and the toluene hydrogens interact with the butyronitrile nitrogen. Comparison of interaction energies shows that the stability of 1:2 complex is more than that of butyronitrile dimer and 1:1 complex. [ABSTRACT FROM AUTHOR]

Treatment of the tris(cyclopentadienyl) thorium(III) complex [Th(η 5 -Cp′′) 3 ] [ 1 , Cp′′ = C 5 H 3 -1,3-(SiMe 3 ) 2 ] with the N -heterocyclic olefin H 2 C=C(NMeCH) 2 ( 2 ) reproducibly produces the thorium(IV)-methyl derivative [Th(η 5 -Cp′′) 3 (Me)] ( 3 ) along with MeImCH 2 CH 2 ImMe (Im = imidazole). The reaction mechanism, which is consistent with 1 H NMR spectroscopic observations, is proposed to proceed via: (i) coordination of 2 to 1 ; (ii) one-electron transfer from thorium to 2 ; (iii) N -methyl cleavage and transfer to thorium to give 3 ; (iv) coupling of the resulting imidazolium radical by-product to give MeImCH 2 CH 2 ImMe. Complex 3 has been characterised by single crystal X-ray diffraction, multi-nuclear NMR and IR spectroscopies, and elemental analyses, and MeImCH 2 CH 2 ImMe by 1 H NMR spectroscopy and mass spectrometry. [ABSTRACT FROM AUTHOR]

The equimolar reaction of [(C 5 Me 5 )LnMe 2 ] 3 (Ln = Y, Lu) with (DippForm)AlMe 2 gave the ligand-rearranged complexes (C 5 Me 5 )Ln(AlMe 4 )(DippForm) in quantitative yields. The half-sandwich complexes were fully characterized including X-ray structure analyses. Donor solvent (THF)-induced alkylaluminate cleavage of (C 5 Me 5 )Lu(AlMe 4 )(DippForm) gave complex [(C 5 Me 5 )LuMe(DippForm)(thf)] exclusively, as evidenced by 1 H‒ 13 C HSQC NMR spectroscopy. Treatment of polymeric [LuMe 3 ] n with formamidine DippFormH produced a mixture of two compounds, namely, the bis(formamidinate) complex (DippForm) 2 LuMe and the methyl methylidene complex [{(DippForm)Lu( μ 2 -Me)} 3 ( μ 3 -Me)( μ 3 -CH 2 )]. While monomeric (DippForm) 2 LuMe revealed a very short Lu–C terminal methyl bond lengths of 2.314(3) Å in the solid state, the structure of the trimetallic methylidene complex could be assigned unambiguously on the basis of a 1 H‒ 13 C HSQC NMR spectrum. Preliminary studies on the performance of complex (C 5 Me 5 )Y(AlMe 4 )(DippForm) in isoprene polymerization revealed that upon activation with borate co-catalysts [Ph 3 C][B(C 6 F 5 ) 4 ] and [PhNMe 2 H][B(C 6 F 5 ) 4 ] highly active catalyst systems are obtained, producing polyisoprenes with dominant 3,4-units (57% and 58%). [ABSTRACT FROM AUTHOR]

Geometries and potential energies of reagents, products, and intermediate states for the reaction between cyclopentadienyl (C5H5) and methyl (CH3) radicals are found by means of ab initio quantum mechanical methods CCSD(T)/cc-pVTZ-f12, B2PLYPD3/AUG-CC-PVDZ and B3LYP/6-311G. Basing on the analysis of the found energy, structural and kinetic characteristics of the compounds involved, the reaction paths leading to the formation of fulvene and benzene, the simplest aromatic compound, are determined. The reaction path begins from the formation of the intermediate compound, methylcyclopentadiene, followed by tearing-off a hydrogen atom from it: C5H5 + CH3 → C5H5CH3 → C5H4CH3 + H. The subsequent monomolecular transformations of C5H4CH3 are closed by the formation of either fulvene (via the loss of one hydrogen atom from the methyl group) or benzene (via the stages of transforming the pentamerous ring into a hexamerous one and tearing-off a hydrogen atom). The rate constants found in the paper using the software package MESS show that the rate of benzene formation is always higher than that for fulvene within the temperature interval 500-2250 K. Since fulvene can also isomerize into benzene, the reaction C5H5 + CH3 is an important supplier of the initial bricks for building polycyclic aromatic hydrocarbons dangerous for living systems.

As previously shown for lutetium and yttrium, 1,2,3,4,5-pentamethylcyclopentadienyl (C5Me5 = Cp*)-bearing rare-earth metal dimethyl half-sandwich complexes [Cp*LnMe2]3 are now also accessible for holmium, dysprosium, and terbium via tetramethylaluminato cleavage of [Cp*Ln(AlMe4)2] with diethyl ether (Ho, Dy) and tert-butyl methyl ether (TBME) (Tb). C−H-bond activation and ligand redistribution reactions are observed in case of terbium and are dominant for the next larger-sized gadolinium, as evidenced by the formation of mixed methyl/methylidene clusters [(Cp*Ln)5(CH2)(Me)8] and metallocene dimers [Cp*2Ln(AlMe4)]2 (Ln = Tb, Gd). Applying TBME as a “cleaving” reagent can result in both TBME deprotonation and ether cleavage, as shown for the formation of the 24-membered macrocycle [(Cp*Gd)2(Me)(CH2OtBu)2(AlMe4)]4 or monolanthanum complex [Cp*La(AlMe4){Me3Al(CH2)OtBu}] and monoyttrium complex [Cp*Y(AlMe4)(Me3AlOtBu)], respectively. Complexes [Cp*Ln(AlMe4)2] (Ln = Ho, Dy, Tb, Gd) and [Cp*LnMe2]3 (Ln = Ho, Dy) are applied in isoprene and 1,3-butadiene polymerization, upon activation with borates [Ph3C][B(C6F5)4] and [PhNHMe2][B(C6F5)4], as well as borane B(C6F5)3. The trans-directing effect of AlMe3 in the binary systems [Cp*Ln(AlMe4)2]/borate is revealed and further corroborated by the fabrication of high-cis-1,4 polybutadiene (97%) with “aluminum-free” [Cp*DyMe2]3/[Ph3C][B(C6F5)4]. The formation of multimetallic active species is supported by the polymerization activity of pre-isolated cluster [(Cp*Ho)3Me4(CH2)(thf)2].

Cp'4U (Cp' = C5H4SiMe3) was synthesized from: (a) KCp' and [Cp'3U(THF)][BPh4]; (b) Cp'3U and Cp'2Pb and (c) [K(2.2.2- cryptand)][Cp'4U] and AgBPh4. The compound was identified by X-ray crystallography as a rare example of a structurally-characterized tetrakis(cyclopentadienyl)UIV complex. For comparison, the corresponding Th complex, Cp'4Th, was isolated from the direct combination of ThBr4(THF)4 with excess KCp'. During the preparation of Cp'3UMe, the precursor of the [Cp'3U(THF)][BPh4] reagent used above, it was discovered that the reaction of Cp'3UCl and MeLi gives a mixture of Cp'3UMe and Cp'3UCl that can co-crystallize better than Cp'3UMe in pure form. The Cp'3UMe/Cp'3UCl mixture forms single crystals suitable for X-ray crystallography and provides a new way to characterize the oil, Cp'3UMe. Cp'3UCl and Cp'3UI were also crystallographically characterized for comparison with the Cp'3UMe/ Cp'3UCl crystals. [ABSTRACT FROM AUTHOR]

The formation of polycyclic aromatic hydrocarbons (PAHs) in high temperature environments is an ongoing area of research due to the mismatch between the experimental and simulated concentration profiles of PAHs in several flames. In this work, the role of methyl radicals in the growth of PAHs is identified by developing a detailed reaction mechanism for the conversion of phenanthrene to pyrene by methyl radicals. The reaction energetics are obtained through quantum calculations using B3LYP and M06-2X functionals along with 6-311++G(d,p) basis set, and are used to compare the competing channels for pyrene formation. The transition state theory is used to determine the reaction kinetics. Through kinetic simulations, the most preferred path for pyrene formation from phenanthrene is determined. To quantify the contribution of the newly found reactions in PAH growth in the presence of other competing PAH mechanisms, the reactions are merged with a recently developed and well-validated mechanism for C 1 C 4 hydrocarbons with detailed PAH chemistry. Three premixed laminar aliphatic flames were simulated with the updated mechanism. It was observed that the new reactions did not appreciably influence the computed profiles of phenanthrene and pyrene. Through the rate-of-production analysis, it was found that the phenanthrene radicals created through H-abstraction were more susceptible to attack by C 2 H 2 than by methyl radicals. The indirect role of methyl radicals in PAH formation and growth is shown. [ABSTRACT FROM AUTHOR]

The reaction of Ru 5 (μ 5 -C)(CO) 15 , 1 with MeAu(PPh 3 ) yielded two major products: Ru 5 (μ 5 -C)(CO) 14 (μ-η 2 -O=CMe)[μ-Au(PPh 3 )], 5 (30% yield) and Ru 5 (μ 5 -C)(CO) 13 (μ-η 2 -O=CMe)(Me)[μ-Au 2 (PPh 3 ) 2 ], 6 (31% yield) and one minor product Ru 5 (μ 5 -C)(CO) 14 (μ-η 2 -O=CMe)(η 1 -O=CMe)[μ-Au 2 (PPh 3 ) 2 ], 7 (2% yield). Compound 6 was also obtained independently in 39% yield by the addition of MeAu(PPh 3 ) to 5 . Compound 7 was also obtained independently in 63% yield by the addition of CO to 6 . The PPh 3 derivative of 5 , Ru 5 (μ 5 -C)(CO) 13 (PPh 3 )(μ-η 2 -O=CMe)[μ-Au(PPh 3 )], 8 was obtained in 76% yield by the reaction of 5 with PPh 3 . Compound 6 eliminates acetone when heated to yield the digold complex Ru 5 (μ 5 -C)(CO) 11 (μ-CO) 2 [μ-Au(PPh 3 )] 2 , 9 . Compound 9 reacts with MeAu(PPh 3 ) to yield the tetragold compound Ru 5 (μ 5 -C)(CO)11(μ-CO) 2 [μ-Au(PPh 3 )] 4 10 . All products have been characterized by single crystal X-ray diffraction analyses. Compounds 5 and 6 contain a bridging acetyl ligand formed by the combination of the methyl group with a CO ligand in opened Ru 5 clusters. Compound 7 contains both a bridging acetyl ligand and a terminally-coordinated acetyl ligand. [ABSTRACT FROM AUTHOR]