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The molecular structure of a crystalline monolayer of hydrocarbon chains was modeled and studied via computer simulation using the Metropolis Monte Carlo algorithm at a temperature T = 300 K. The only interactions in this system occur through Lennard‐Jones dispersion forces and short‐range atom‐atom repulsion. The intent was to establish whether the chains were either rigidly extended or twisted via the thermal formation of gauche bonds and apply the results to understand observations made on two possible oleogelators: triacontane and stearic acid. Specifically, we aimed to understand if their observed crystalline monolayer thicknesses are due to gauche‐bond‐shortened hydrocarbon chains oriented perpendicular to the monolayer surface, or to fully extended rigid chains oriented at a tilt angle with respect to the surface. The results showed that crystals of hydrocarbon chains did not include significant gauche bonds, so that all molecules were rigidly extended, thus explaining the experimental data previously reported. Accordingly, TC and SA dimer molecules are packed in crystalline multilayers with tilt angles in relation to the methyl group plane. [ABSTRACT FROM AUTHOR]

The complexity of crude oil composition, combined with the fluctuating oxygen level in contaminated environments, poses challenges for the bioremediation of oil pollutants, because of compound-specific microbial degradation of petroleum hydrocarbons under certain conditions. As a result, facultative bacteria capable of breaking down petroleum hydrocarbons under both aerobic and anaerobic conditions are presumably effective, however, this hypothesis has not been directly tested. In the current investigation, Shewanella putrefaciens CN32, a facultative anaerobic bacterium, was used to degrade petroleum hydrocarbons aerobically (using O2 as an electron acceptor) and anaerobically (using Fe(III) as an electron acceptor). Under aerobic conditions, CN32 degraded more saturates (65.65 ± 0.01%) than aromatics (43.86 ± 0.03%), with the following order of degradation: dibenzofurans > n-alkanes > biphenyls > fluorenes > naphthalenes > alkylcyclohexanes > dibenzothiophenes > phenanthrenes. In contrast, under anaerobic conditions, CN32 exhibited a higher degradation of aromatics (53.94 ± 0.02%) than saturates (23.36 ± 0.01%), with the following order of degradation: dibenzofurans > fluorenes > biphenyls > naphthalenes > dibenzothiophenes > phenanthrenes > n-alkanes > alkylcyclohexanes. The upregulation of 4-hydroxy-3-polyprenylbenzoate decarboxylase (ubiD), which plays a crucial role in breaking down resistant aromatic compounds, was correlated with the anaerobic degradation of aromatics. At the molecular level, CN32 exhibited a higher efficiency in degrading n-alkanes with low and high carbon numbers relative to those with medium carbon chain lengths. In addition, the degradation of polycyclic aromatic hydrocarbons (PAHs) under both aerobic and anaerobic conditions became increasingly difficult with increased numbers of benzene rings and methyl groups. This study offers a potential solution for the development of targeted remediation of pollutants under oscillating redox conditions. [ABSTRACT FROM AUTHOR]

Beryllium ammonia complexes Be(NH3)4 are known to bear two diffuse electrons in the periphery of a Be(NH3)42+ skeleton. The replacement of one ammonia with a methyl group forms CH3Be(NH3)3 with one peripheral electron, which is shown to maintain the hydrogenic-type shell model observed for Li(NH3)4. Two CH3Be(NH3)3 monomers are together linked by aliphatic chains to form strongly bound beryllium ammonia complexes, (NH3)3Be(CH2)nBe(NH3)3, n = 1–6, with one electron around each beryllium ammonia center. In the case of a linear carbon chain, this system can be seen as the analog of two hydrogen atoms approaching each other at specific distances (determined by n). We show that the two electrons occupy diffuse s-type orbitals and can couple exactly as in H2 in either a triplet or singlet state. For long hydrocarbon chains, the singlet is an open-shell singlet nearly degenerate with the triplet spin state, which transforms to a closed-shell singlet for n = 1 imitating the σ-covalent bond of H2. The biradical character of the system is analyzed, and the singlet–triplet splitting is estimated as a function of n based on multi-reference calculations. Finally, we consider the case of bent hydrocarbon chains, which allows the closer proximity of the two diffuse electrons for larger chains and the formation of a direct covalent bond between the two diffuse electrons, which happens for two Li(NH3)4 complexes converting the open-shell to closed-shell singlets. The energy cost for bending the hydrocarbon chain is nearly compensated by the formation of the weak covalent bond rendering bent and linear structures nearly isoenergetic. [ABSTRACT FROM AUTHOR]

Fe-bearing clay minerals are frequently present in oil reservoirs as potential electron acceptor. Compounds in crude oil may mediate microbial reduction of structural Fe(III) in clay minerals through their roles as electron donor and shuttle. However, there is limited knowledge about these roles and resulting transformation of oil compounds. In this study, bio-reduction of structural Fe(III) in nontronite (NAu-2, Fe-rich smectite) by the dissimilatory iron-reducing bacterium (DIRB) Shewanella putrefaciens CN32 was investigated in the presence of either crude oil or specific fractions of oil. Lactate was added in some experiments as extra electron donor. The fractions of saturates (nC 14 -nC 20 alkanes and nC 8 -nC 14 -alkyl cyclohexanes), aromatics (with two/three benzene rings), and polar compounds (carboxylic acids) of crude oil were adsorbed to NAu-2 surface. Without CN32, crude oil was able to slightly reduce structural Fe(III) in NAu-2. In the presence of CN32, reduction of Fe(III) in NAu-2 was coupled with oxidation of bulk oil and saturated/aromatic fractions. The reduction extent (21.5 ± 0.3%) and rate (0.04 ± 0.00 mM/h) by the saturated oil fraction (nC 17 -nC 30 alkanes and nC 10 -nC 23 -alkyl cyclohexanes as electron donors) were slightly lower than those by bulk oil (22.8 ± 0.4% and 0.05 ± 0.00 mM/h, respectively), but those by the aromatic fraction with two benzene rings were much higher (30.8 ± 0.2% and 0.15 ± 0.00 mM/h, respectively). Fe(III) bio-reduction was coupled with oxidative transformation of oil compounds. Specifically, n -alkanes and alkyl cyclohexanes with shorter carbon chains and aromatic isomers with fewer methyl groups were more easily degraded (i.e., dibenzothiophene series) and/or desorbed (i.e., phenanthrene series) than n -alkanes and alkyl cyclohexanes with longer carbon chains and aromatic isomers with more methyl groups. These hydrocarbons were degraded to oxygen-containing compounds, mainly saturated fatty acids, monocyclic naphthenic acids, and phenols. In the presence of lactate as extra electron donor, the aromatic fraction significantly promoted the Fe(III) bio-reduction extent and rate, suggesting its role as electron shuttle. The oxidative transformation of oil compounds driven by bio-reduction of clay minerals has broad implications for the coupled biogeochemical cycles of carbon and iron in oil reservoirs and organic-rich sedimentary rocks. [ABSTRACT FROM AUTHOR]

[Display omitted] • Genome mining of three gene clusters results in four new fusicoccane diterpenoids. • C5 Oxidation of the fusicoccane skeleton causes broadening NMR signals, which was resolved by variable-temperature NMR. • MgP450 is the first enzyme for hydroxylation of the C19 methyl group of the fusicoccane core. • NpP450 acts as a multifunctional P450 enzyme for oxidation at C5, C6, and C19 of the fusicoccane skeleton. Fusicoccane (FC)-type diterpenoids are a class of diterpenoids characterized by a unique 5–8–5 ring system and exhibit diverse biological activities. Recently, we identified a novel FC-type diterpene synthase MgMS, which produces a myrothec-15(17)-en-7-ol (1) hydrocarbon skeleton, however, its tailoring congeners have not been elucidated. Here, we discovered two additional gene clusters Bn and Np , each encoding a highly homologous terpene synthase to MgMS but distinct tailoring enzymes. Heterologous expression of the terpene synthases BnMS and NpMS yielded the same product as MgMS. Subsequent introduction of three P450 enzymes MgP450, BnP450 and NpP450 from individual gene clusters resulted in four new FC-type diterpenoids 2 – 5. Notably, MgP450 serves as the first enzyme responsible for hydroxylation of the C19 methyl group, whereas NpP450 functions as a multifunctional P450 enzyme involved in the oxidations at C5, C6, and C19 positions of the 5–8–5 tricyclic skeleton. C5 oxidation of the hydrocarbon skeleton 1 led to broadening of the NMR signals and incomplete spectra, which was resolved by high-temperature NMR spectral analysis. [ABSTRACT FROM AUTHOR]

Vibrational sum frequency generation spectroscopy is used to characterize octadecylsiloxane monolayers on glass substrates at ambient conditions with a focus on thermally induced conformational disorder. Different modes of the C-H stretching vibrations of the terminal methyl groups and the methylene groups are therefore monitored in the frequency range of 2850-3000 cm-1. We observe a progressive increase of conformational disorder of the alkyl chains due to gauche defects over the temperature range from 300 to 510 K. The conformational disorder is reversible over a temperature range from 300 to about 410 K. But after heating to temperatures above 410 K, order is not reestablished on the time scale of the experiment. These results suggest that the assumption of an all-trans configuration of the alkyl chains is an over-simplification which increasingly misrepresents the situation for elevated temperatures which are still well below the one at which decomposition starts. [ABSTRACT FROM AUTHOR]

A multifunctional sorbent for the separation of microquantities of elements-analogues of the aluminum subgroup was obtained by impregnation of the dimethylchlorosilanaerosyl (DMCSA) surface with a polar organic solvent (POS). The surface identification of the organized DMCSA - POS system was performed via diffuse reflection spectroscopy. The results of the study of Al (III), Ga (III), In (III) sorption using an organized system DMCSA - POS depending on the medium acidity and the nature of POS (ethanol or acetone) showed that the quantitative and selective removal of the studied elements corresponds to the formation of the neutral hydroxoforms and is due to kinetic and thermodynamic differences in the ability of Al (III), Ga (III), In (III) to hydrolysis. A participation in adsorption-extraction processes hydrophobically attached to the methyl groups of DMCSA layer POS also takes place. A method of stepwise separation of Al (III), Ga (III), In (III) from their three- and multicomponent mixtures is proposed. At the same initial concentrations of elements, the values of the separation coefficients of pairs Ga (III) - In (III) ≈ 1450 and In (III) - Al (III) ≈ 450 were calculated. [ABSTRACT FROM AUTHOR]

Background and Purpose: Chronic neuropathic pain (NEP) is associated with growing therapeutic cannabis use. To promote quality of life without psychotropic effects, cannabinoids other than Δ9-tetrahydrocannabidiol, including cannabidiol and its precursor cannabidiolic acid (CBDA), are being evaluated. Due to its instability, CBDA has been understudied, particularly as an anti-nociceptive agent. Adding a methyl ester group (CBDA-ME) significantly enhances its stability, facilitating analyses of its analgesic effects in vivo. This study examines early treatment efficacy of CBDA-ME in a rat model of peripherally induced NEP and evaluates sex as a biological variable.Experimental Approach: After 14 consecutive days of intraperitoneal CBDA-ME administration at 0.01, 0.1 and 1 μg·kg-1 , commencing 1 day after surgically implanting a sciatic nerve-constricting cuff to induce NEP, the anti-nociceptive efficacy of this cannabinoid was assessed in male and female Sprague-Dawley rats relative to vehicle-treated counterparts. In females, 2 and 4 μg·kg-1 daily doses of CBDA-ME were also evaluated. Behavioural tests were performed for hind paw mechanical and thermal withdrawal thresholds once a week for 8 weeks. At endpoint, in vivo electrophysiological recordings were obtained to characterize soma threshold changes in primary sensory neurons.Key Results: In males, CBDA-ME elicited a significant concentration-dependent chronic anti-hyperalgesic effect, also influencing both nociceptive and non-nociceptive mechanoreceptors, which were not observed in females at any of the concentrations tested.Conclusion and Implications: Initiating treatment of a peripheral nerve injury with CBDA-ME at an early stage post-surgery provides anti-nociception in males, warranting further investigation into potential sexual dimorphisms underlying this response. [ABSTRACT FROM AUTHOR]

The rotational motion of the methyl group in pentafluoroanisole (PFA) and in pentafluorotoluene (PFT), respectively, was investigated by quasielastic neutron scattering (QENS). For solid PFA, the rotation can be described by a model for uniaxial rotational jumps between three equidistant sites on a circle. Similar to the molecular structure of α-toluene, two nonequivalent methyl groups in the unit cell with two different rotational barriers were found for solid PFT. From the analysis of the quasielastic scattering, the activation energies were determined. The barrier heights could be evaluated from bands in the inelastic part of the spectra. The methyl group dynamics in the liquid state is evaluated for both substances using different scattering functions, which are discussed. An empirical model for the description of the contribution of methyl groups in liquids of small organic molecules to the QENS spectra is presented. It is demonstrated that the process of methyl group rotation in the liquid phase is nearly free of a barrier. [ABSTRACT FROM AUTHOR]

Quasielastic neutron scattering experiments were carried out using the multichopper time-of-flight spectrometer V3 at the Hahn-Meitner Institut, Germany and the backscattering spectrometer at Forschungszentrum Jülich, Germany. Activation energies for CH3X, X=F, Cl, Br, and I, were obtained. In combination with results from previous inelastic neutron scattering experiments the data were taken to describe the dynamics of the halides in terms of two different models, the single particle model and the coupling model. Coupled motions of methyl groups seem to explain the dynamics of the methyl fluoride and chloride; however, the coupling vanishes with the increase of the mass of the halide atom in CH3Br and CH3I. [ABSTRACT FROM AUTHOR]

Plasma-induced damages of porous silica films during plasma processes were investigated by using a plasma beam irradiation apparatus. We used the porous silica films incorporated with methyl groups to achieve high hydrophobicity. The carbon (methyl group) reductions in the film as an index of the level of damages induced by Ar, He, O2, H2, and N2 plasma irradiations were examined by x-ray photoelectron spectroscopy and secondary ion mass spectroscopy. The damage due to Ar and He plasma bombardment increased with an increase in the ion dosage, although it was not strongly affected by the ion energy in the range higher than 130 eV. Furthermore, it was found that the damage near the film surface was influenced more by metastable He atoms than by metastable Ar atoms. Both O ions and O atoms caused severe damage. N atoms did not affect the decrease of carbon content but reacted with carbon to form CN bonds. H atoms decreased carbon content slightly, but the amount of decrease was saturated by the further irradiation of H atoms. [ABSTRACT FROM AUTHOR]

The 1:1 hexamethylbenzene (HMB)-tetracyanoquinodimethane (TCNQ) complex shows a first-order phase transition at 230/218 K (heating/cooling) with no change of the space group. The neutron-diffraction studies reveal that this transition is related to a freezing of the rotation of methyl groups. The results for 100 K enabled precise determination of configuration of HMB·TCNQ complexes. The planes of HMB and TCNQ molecules from small angle (6°) so that the dicyanomethylene group approaches the HMB molecule to a distance of 3.34 Å. The conformation of methyl groups was exactly determined. The quasielastic neutron-scattering spectra can be interpreted in terms of 120° jumps with different activation barrier in low- and high-temperature phases, equal to 3.7 and 1.8 kJ/mol, respectively. These values are lower than that for neat HMB (6 kJ/mol). The conclusion can be drawn that the methyl groups can reorient more freely in the complex. This conclusion is in agreement with the results of inelastic neutron-scattering studies of low-frequency modes assigned to torsional vibrations of methyl groups. These frequencies are lower than those for neat HMB. The analyzed increase of frequencies of these modes as compared with free molecules can be interpreted as due to formation of unconventional C–H...Y hydrogen bonds which are more pronounced in crystals of neat HMB than in those of HMB·TCNQ. The low-frequency librational modes can be treated as a sensitive measure of unconventional hydrogen bonds formed by the CH3 groups. [ABSTRACT FROM AUTHOR]

A theoretical model for the ultrafast S1→S0 internal conversion of cytosine is presented, in which a state switch from the initially prepared 1ππ* state to the out-of-plane deformed excited state of biradical character controls the rate of the S1(1ππ*) decay. This mechanism successfully accounts for the dramatically longer S1 lifetimes of 5-fluorocytosine and N-acetylcytosine relative to cytosine. The replacement of the C5 hydrogen atom by a methyl group is predicted to lead to a substantial, but not dramatic, increase in the S1 lifetime, also consistent with experiment. It is this ability to correctly predict the substituent effects that distinguishes the present model from the previously proposed mechanisms. [ABSTRACT FROM AUTHOR]

Site-specific chemical modification, especially with isotopically enriched groups, allows one to study the structure and dynamics of proteins for which uniform enrichment is difficult. When the N-terminal alanine in antifreeze glycoprotein (AFGP) is replaced with an N,N-dimethyl alanine the methyl groups show signatures of slow rotation about the C–N bond. In order to separate the local dynamics of the N-terminus from the overall protein dynamics, we present a complete characterization of this dynamics. Temperature-dependent nuclear magnetic-resonance experiments from room temperature to subzero temperatures, including the supercooled state and in the presence of ice, are presented. Quantum chemical calculations are also performed on a localized N-terminus of the AFGP. Our results show that in the solution state at room temperature and in the super cooled regime, the dimethyl groups undergo a slow, restricted rotation with an unequal distribution of population between two major conformations. At lower temperatures in the presence of ice, the dynamics become much more complex due to freezing out of several conformational states. Based on these results, we conclude that the segmental dynamics of the N-terminus are local to the first residue and do not affect the overall dynamics of the protein. [ABSTRACT FROM AUTHOR]

We propose a minimum principle to derive a QM/MM (quantum-mechanical/molecular-mechanical) method from the first principle. We approximate the Hamiltonian of a spectator substituent as the structure-dependent effective Hamiltonian in a least-squares sense. This effective Hamiltonian is expanded with the orthogonal operator set called the normal-ordered product. We determine the structure-dependent energy that corresponds to the classical MM energy and the extra one-electron potential that takes account of the interface effects. This QM/MM method is free from the double-counting problem and the artificial truncation of the localized molecular orbitals. As a numerical example we determine the one-electron effective Hamiltonian of the methyl group. This effective Hamiltonian is applied to the ethane and CH3CH2X molecules (X=CH3, NH2, OH, F, COOH, NH3+, OH2+, and COO-). It reproduced the relative energies, potential energy curves, and the Mulliken populations of the all-electron calculations fairly well. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In this work we present a study of the F+CH[sub 4]→HF+CH[sub 3] reaction (ΔH[sub 298 K][sup °]=-32.0kcal mol[sup -1]) using different methods of the chemical reaction theory. The ground potential energy surface (PES) is characterized using several ab initio methods. Full-dimensional rate constants have been calculated employing the variational transition state theory and using directly ab initio data. A triatomic analytical representation of the ground PES was derived from ab initio points calculated at the second- and fourth-order Møller–Plesset levels with the 6-311+G(2df,2pd) basis set, assuming the CH[sub 3] fragment to be a 15 a.m.u. pseudoatom in the fitting process. This is suggested from experiments that indicate that the methyl group is uncoupled to the reaction coordinate. A dynamics study by means of the quasiclassical trajectory (QCT) method and employing this analytical surface was also carried out. The experimental data available on the HF internal states distributions are reproduced by the QCT results. Very recent experimental information about the reaction stereodynamics is also borne out by our QCT calculations. Comparisons with the benchmark F+H[sub 2] and analogous Cl+CH[sub 4] reactions are established throughout. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A few theoretical and experimental studies have been done so far about the properties and the conformational analysis of alkenes as monomers and dimers. Deeper insights into the conformational analysis of monomers and dimers of alkenes and the relation with boiling point are done in this work. In low-lying cis-butene, there is no repulsive interaction between methyl groups but there is an attractive hydrogen-hydrogen bonding. In monomers of 1-alkenes, the most stable conformer has bent-inward geometry which favors the π bond interaction with methyl/methylene hydrogen/carbon atoms. Conversely, each alkene's molecule in the corresponding most stable alkene's dimer has a straight, zig-zag geometry. Two straight, zig-zag alkene's molecules in the corresponding most stable dimer have only one type of intermolecular interaction (hydrogen-hydrogen bonding). As a consequence, very good linear relationships between a physical property (such as boiling point) and theoretical parameters are obtained. [ABSTRACT FROM AUTHOR]

The century-old puzzle of the existence of a quasiliquid layer in the surface of ice was revisited using ice-surface binding type I antifreeze proteins with specific side chain 13C labeled methyl groups. Variable temperature dependent 13C spin lattice relaxation NMR experiments were carried out below 0 °C to probe the water molecular reorientations surrounding the methyl groups. The result shows that water molecular reorientations in ice surface are much more dynamic than those in bulk ice. This study demonstrates that antifreeze proteins can be used as a sensor to detect the dynamics of water in the surface of ice. [ABSTRACT FROM AUTHOR]

X-ray diffraction experiments are employed to determine the molecular and crystal structure of 3-isopropylchrysene. Based on this structure, electronic structure calculations are employed to calculate methyl group and isopropyl group rotational barriers in a central molecule of a ten-molecule cluster. The two slightly inequivalent methyl group barriers are found to be 12 and 15 kJ mol-1 and the isopropyl group barrier is found to be about 240 kJ mol-1, meaning that isopropyl group rotation is completely quenched in the solid state. For comparison, electronic structure calculations are also performed in the isolated molecule, determining both the structure and the rotational barriers, which are determined to be 15 kJ mol-1 for both the isopropyl group and the two equivalent methyl groups. These calculations are compared with, and are consistent with, previously published NMR 1H spin-lattice relaxation experiments where it was found that the barrier for methyl group rotation was 11±1 kJ mol-1 and that the barrier for isopropyl group rotation was infinite on the solid state NMR time scale. [ABSTRACT FROM AUTHOR]

Abstract: The correlation between oxidation state and Lewis acidity is well established for hexaquairon complexes in the +II and +III oxidation state, in which the higher oxidation state leads to a lower pKa for the bound H2O ligand. This article addresses the Lewis acidity of the oxoiron(IV) complex [FeIV(O)(TMC)(OH2)]2+ (1‐OH2; TMC=1,4,8,11‐tetramethylcyclam) by determining the pKa of the H2O ligand. We establish that 1‐OH2 has a pKa of 6.9±0.5, a value that falls in between those found for [FeIII(OH2)6]3+ and [FeII(OH2)6]2+. This intermediate value can be readily rationalized by the presence of the highly basic oxide ligand that mitigates the Lewis acidity of the iron(IV) center. Although the oxo ligand occupies only one position in 1‐OH2, anti to all four methyl groups that protrude from the same face of the nonplanar TMC ligand, its conjugate base 1‐OH exists as a mixture of syn and anti tautomers, which are related by proton transfer between the oxo and the hydroxo ligands. [ABSTRACT FROM AUTHOR]

Engineering the Wood-Ljungdahl pathway (WLP) in the established industrial organism Clostridium acetobutylicum would allow for the conversion of carbohydrates into butanol, acetone, and other metabolites at higher yields than are currently possible, while minimizing CO2 and H2 release. To this effect, we expressed 11 Clostridium ljungdahlii core genes coding for enzymes and accessory proteins of the WLP in Clostridium acetobutylicum. The engineered WLP in C. acetobutylicum showed functionality of the eastern branch of the pathway based on the formation of labeled 5,10- methylenetetrahydrofolate from 13C-labeled formate, as well as functionality of the western branch as evidenced by the formation of CO from CO2. However, the lack of labeling in acetate and butyrate pools indicated that the connection between the two branches is not functional. The focus of our investigation then centered on the functional expression of the acetyl-coenzyme A (CoA) synthase (ACS), which forms a complex with the CO dehydrogenase (CODH) and serves to link the two branches of the WLP. The CODH/ACS complex catalyzes the reduction of CO2 to CO and the condensation of CO with a methyl group to form acetyl-CoA, respectively. Here, we show the simultaneous activities of the two recombinant enzymes. We demonstrate in vivo the classical in vitro ACS carbonyl carbon exchange assay, whereby the carbonyl carbon of acetyl-CoA is exchanged with the CO carbon. Our data suggest that the low heterologous expression of ACS may limit the functionality of the heterologous WLP in C. acetobutylicum. IMPORTANCE The bifunctional carbon monoxide dehydrogenase/acetyl-CoA synthase (CODH/ACS) from C. ljungdahlii was heterologously expressed in the obligate heterotroph C. acetobutylicum. The functional activity of the CODH was confirmed through both the oxidation and reduction of CO, as had previously been shown for the heterologous CODH from Clostridium carboxidivorans. Significantly, a novel in vivo assay for ACS exchange activity using 13C-tracers was developed and used to confirm functional ACS expression. [ABSTRACT FROM AUTHOR]

An unknown compound dominant in the aliphatic hydrocarbon fraction of the solvent extract of a Dominican amber sample was isolated and purified using column chromatography and preparative gas chromatography. 1D and 2D NMR analyses allowed its structure to be assigned as 15- nor- cleroda-3,12-diene. The bridgehead methyl group (CH 3 at C-19) has a 13 C chemical shift of 19.6 ppm, typical for a trans -decalin framework (Nogueira, 2001), indicating the diterpenoid has a trans A/B ring structure. ROESY correlations indicate that the methyl groups at C-19, C-20 were axial and the C-17 methyl group was equatorial, while the H-10 and H-8 were axial and on the other side of Ring B. Taken together, a 5 R ,8 R ,9 S ,10 R -configuration for the new nor-clerodadiene can be established. The absolute configuration of 5 R ,8 R ,9 S ,10 R was further confirmed by comparing the experimental and calculated electronic circular dichroism (ECD) spectra of this diterpenoid. The identified diene appears to originate from a Hymenaea species ( Fabaceae ). Non-oxidative decarboxylation of cleroda-3,13-diene-15-oic acid (kovalenic acid) present in Hymenaea species or oxidative decarboxylation of 3-cleroden-15-oic acid in Dominican amber are considered to be the two viable pathways leading to the formation of the identified 15- nor -cleroda-3,12-diene, although the former pathway is more likely. [ABSTRACT FROM AUTHOR]

Until recently, the chemistry of boronyl (BO), a diatomic radical isolectronic with the cyano (CN) species, has remained unknown. The boronyl group is characterized by a boron-oxygen multiple bond, and because of the inherent electron deficiency of the boron atom, boronyls (RBO) are highly reactive and typically only exist in their cyclotrimeric form (RBO)3. Due to their invaluable role as reactants, the isolation of the monomers in gas phase experiments has been extensively sought after by the organic synthesis and physical organic chemistry communities but never achieved. Besides the interests from a physical organic and synthetic point of view, boronyls also play a role as reaction intermediates in boron-assisted rocket propulsion systems.In this Account, we review recent experimental work in which gas phase organo boronyl monomers (RBO) are formed via bimolecular reactions of the boronyl radical (BO) with C2-C6 unsaturated hydrocarbons. The investigated hydrocarbons are widely exploited as fuels, and their reactions with boronyl radicals under single collision conditions lead to the formation of organo boronyls. Our studies also elucidate the mechanisms of their formation reactions thus furnishing a comprehension at the molecular level of this reaction class. The variety of the employed hydrocarbon substrates has allowed us to systematically classify the chemical behavior of the boronyl radicals. With the exception of the case of the dimethylacetylene reaction, the boron monoxide radical versus atomic hydrogen exchange mechanisms were always open leading to the formation of highly unsaturated organo boronyl monomers (RBO), which could be easily identified because they cannot trimerize under single collision conditions.Besides the hydrogen displacement pathway, methylacetylene, dimethylacetylene, and propylene, carrying one or two methyl groups, were also found to eliminate a methyl group. In all systems, the reactions were barrierless, indirect, and initiated by addition of the boron monoxide radical to the π electron density of the hydrocarbon molecule, with the radical center located at the boron atom of the BO radical, thus leading to doublet radical intermediates. These intermediates either decompose via hydrogen or methyl loss or isomerize prior to their decomposition via atomic hydrogen or migration of the BO moiety. A consistent trend suggests that all exit transition states are rather tight with those involved in the hydrogen atom loss depicting exit barriers of typically 25 to 35 kJ mol-1, whereas the methyl loss pathways are associated with tighter exit transition states located about 30-50 kJ mol-1 above the separated products. Further, the overall energetics suggest that those bimolecular reactions are exoergic by 40-90 kJ mol-1. These findings confirm that this reaction class leads to the formation of highly unsaturated organo boronyl molecules. [ABSTRACT FROM AUTHOR]

• Co-feeding CO decreases catalyst lifetime and affects selectivity during MTH on MFI. • The effects of CO depend on zeolite morphology and topology and feed composition. • Reaction-transport formalism reveals morphology-dependent carbonylation and MTH rates. Methanol-to-hydrocarbons catalysis over HZSM-5 at low methanol partial pressure exhibited low steady-state ethylene and aromatics selectivity at sub-complete methanol conversion. Co-feeding CO increases cumulative carbon ratio of ethylene to the sum of 2-methylbutane and 2-methyl-2-butene (>3×) at the expense of catalyst stability, quantified by >18× increase in site-loss yield, and hydrocarbons selectivity (<80 %). These observations can be rationalized by CO incorporation into the hydrocarbon pool via carbonylation of methyl groups to increase propagation of the aromatics-cycle and of termination sequences relative to that of the olefins cycle. The effects of CO become more prominent at higher partial pressures of CO, at lower inlet concentrations of methanol, olefins, and aromatics, and upon decreasing proton density (per unit volume) and crystallite size in MFI materials. The morphology- and process-dependent effects of CO during MTH on MFI are manifestations of differences in space- and time-averaged relative carbonylation and methylation rates. Both structural catalyst properties and process conditions affect reaction rates during MTH by affecting diffusional constraints, number and contact time of active chain carriers. These results extend to syngas-to-hydrocarbons conversion where high-pressure CO is present to guide the choice of reaction conditions and materials that maximize catalyst lifetime and modulate product selectivity. [ABSTRACT FROM AUTHOR]

In this work, cuticular waxes from flag leaf blades and peduncles of Triticum aestivum cv. Bethlehem were investigated in search for novel wax compounds. Seven wax compound classes were detected that had previously not been reported, and their structures were elucidated using gas chromatography-mass spectrometry of various derivatives. Six of the classes were identified as series of homologs differing by two methylene units, while the seventh was a homologous series with homologs with single methylene unit differences. In the waxes of flag leaf blades, secondary alcohols (predominantly C27 and C33), primary/secondary diols (predominantly C28) and esters of primary/secondary diols (predominantly C50, combining C28 diol with C22 acid) were found, all sharing similar secondary hydroxyl group positions at and around C-12 or ω-12. 7- and 8-hydroxy-2-alkanol esters (predominantly C35), 7- and 8-oxo-2-alkanol esters (predominantly C35), and 4-alkylbutan-4-olides (predominantly C28) were found both in flag leaf and peduncle wax mixtures. Finally, a series of even- and odd-numbered alkane homologs was identified in both leaf and peduncle waxes, with an internal methyl branch preferentially on C-11 and C-13 of homologs with even total carbon number and on C-12 of odd-numbered homologs. Biosynthetic pathways are suggested for all compounds, based on common structural features and matching chain length profiles with other wheat wax compound classes. [ABSTRACT FROM AUTHOR]

Densities of aqueous solutions of achiral cis -dimethylglycoluril (2,8-DMGU) and chiral (in the racemic form) trans -dimethylglycoluril (2,6-DMGU) were measured using a hermetically sealed vibrating-tube densimeter, with an uncertainty of ~ 1 × 10 − 5 g ∙ cm − 3 , at T = (278.15, 288.15, 298.15, 308.15, and 318.15) K and p = (99.6 ± 0.4) kPa. The solution molality was ranged from (0.037 to 0.396) mol·kg − 1 for aqueous 2,6-DMGU and from (0.046 to 0.202) mol·kg − 1 for aqueous 2,8-DEGU. The standard (at infinite dilution) molar volumes and isobaric molar expansibilities for the specified N -dimethyl-substituted heterocyclic compounds in water were computed and discussed in comparison with previously derived results for the equimolecular 2,4-dimethylglycoluril (2,4-DMGU) whose isomeric molecules contain simultaneously both the unsubstituted and fully methylated five-membered rings. It was established that the compared glycoluril-derivatives are the prevailingly structure-breaking solutes in water despite of presence of two methyl groups in each of heterocyclic molecules. In other words, the hydrophobic hydration effect is being less pronounced than the hydrophilic hydration or H-bonding effect (via amide and carbonyl groups). The temperature-dependent behavior of packing-related hydration effects was described taking into account the structural (stereochemical) features of a solute molecule. [ABSTRACT FROM AUTHOR]

This study examines the effects of the Si/Al ratio and metal cation exchange of a zeolite on the ability to adsorb and reform unburned hydrocarbons (HCs) in emissions from gasoline vehicles. Iron ion-exchanged β-zeolites with a low Si/Al ratio not only trap but also oxidize HCs efficiently, which spurred on the development of a 'super HC reformer trap'. Toluene temperature-programmed desorption experiments in an O2-containing stream revealed that >90 % of the adsorbed toluene was converted into CO2, and other oxygenates were not observed. This material could be reused and it retained its performance. The strong adsorption of toluene on the zeolites was derived from two synergistic effects: (1) electrostatic interactions between the π orbital of the aromatic ring and the p orbital of the metal cation and (2) interactions between the positively polarized methyl group of toluene and a basic oxygen atom in the zeolite framework. This new material will pave the way for low-emission, Pt-free vehicles. [ABSTRACT FROM AUTHOR]

The first regio- and stereoselective total synthesis of the axially chiral 7,3′-coupled naphthylisoquinoline alkaloids ancistrocladidine ( 1) and ancistrotectorine ( 2) has been described. Both possess a 7,3′-coupled axis, which before now, was difficult to attain synthetically. Moreover, target 2 has a sensitive relative cis-array of the two methyl groups at C1 and C3 in the tetrahydroisoquinoline part. The key step in the chosen strategy was the construction of the biaryl axis in accordance with the 'lactone method': the two molecular halves, which were activated in an 'inverse-halogenated' form, were prefixed by an ester bridge, followed by intramolecular coupling, and atroposelective cleavage of the lactone auxiliary bridge delivered the desired biaryl scaffold. [ABSTRACT FROM AUTHOR]

Enantioselective C--H functionalization of relatively electron-deficient methyl sites was achieved with the combination of 2,2,2-trichloroethyl aryldiazoacetates and tetrakis(triarylcyclopropanecarboxylate) dirhodium catalysts. The substrate scope of the transformation was relatively broad, and C--H functionalization products were furnished with excellent levels of enantioselectivity. As a strategic reaction, crotonate derivatives give 1,6-dicarbonyl compounds, which are useful for further diversification. [ABSTRACT FROM AUTHOR]

The preparation of heteroaryl trifluoromethyl selenoethers by the trifluoromethylselenolation of heteroaryl bromides with [(bpy)CuSeCF3]2 was investigated. Using this approach, a large number of trifluoromethylselenolated heterocyclic compounds were synthesized in good to excellent yields. It was demonstrated that this procedure tolerates a wide variety of functional groups. [ABSTRACT FROM AUTHOR]

The dynamics of the C–Br bond dissociation on UV excitation of methyl 2-bromopropionate mainly to the 1 (nσ * ) state, repulsive in the C–Br bond, has been investigated, employing resonance-enhanced multiphoton ionization. Both the ground state and spin-orbits excited bromine atoms were detected, with the former being the major channel. Bromine fragments show bimodal translational energy distributions, with slow and fast (major) bromine atoms arising mainly from the ground and excited electronic states, respectively. The measured recoil anisotropy suggests isotropic angular distributions of bromine atoms. Molecular orbital calculations reveal an important role of avoided curve crossing on C–Br bond dissociation dynamics. [ABSTRACT FROM AUTHOR]

The reaction of germylone (L)Ge (1) [L = 3-Ad-1-{C(tBu) = N(Mes)}C3H4N2] with 1 equivalent of MeOTf afforded a germyliumylidene ion [(L)GeMe]+OTf− (2), while reactions with M(CO)5(thf) (M = Cr, Mo, W) gave the corresponding germylone-metal complexes [(L)Ge]M(CO)5 (3–5). The former possesses a pyramidal Ge center, whereas the latter display a planar geometry around the Ge atom. Computational studies showed a unique bonding interaction between 1 and the M(CO)5 unit, which involves a σ-donation as well as a weak π-back-donation. [ABSTRACT FROM AUTHOR]

Inefficient conversion of structure-complicated and oxygen-enriched asphaltenes is found as the major challenge facing coal tar in achieving high value-added utilization. Hydrogenation technology is the primary way to achieve the impurity removal and lightweight of coal tar asphaltenes (CTAS). In this study, the evolution laws of functional groups and structural parameters at different reaction times, and pyrolysis behavior at different temperatures of coal tar asphaltenes (CTAS) during the hydrotreating (HDT) process were investigated using the methods of FT-IR, XPS, 1H NMR, 13C NMR and Py-GC/MS. It was found that the increase of the reaction time significantly affected CTAS hydrodeoxygenation (HDO), and most of nitrogen-containing compounds (NCs) and sulfur-containing compounds (SCs) could be removed in a shorter reaction time. However, the increase of the reaction time has a limited effect on the removal of NCs and SCs embedded in polycyclic aromatic compounds. The average alkyl chain length (L) decreased with the increase of the reaction time, and the degree of branching for alkyl side chains (B) increased after HDT. The aromatic ring substitution degree (σ) and alkyl substituents number (n) of CTAS increased after HDT. The OH-OH and OH-ether O were found as the major hydrogen bonds in asphaltene feed (Asp-feed) and asphaltene product (Asp-product), followed by OH-π and cyclic OH. With the increase of reaction time, the molar fraction of the OH-ether O hydrogen bonds increased, while OH-π hydrogen bonds decreased. C-O group was found as the critical oxygen-containing functional group in Asp-feed and Asp-product, primarily existing in the form of aromatic ether groups and C-O of phenols. With the increase of reaction time, the molar fraction of aromatic ether groups in CTAS increased significantly, while that of the C-O of phenols decreased. The pyrolysis fragments of Asp-feed and Asp-product were largely 1–3 ring aromatic hydrocarbons or heteroatoms compounds. Heteroatoms compounds primarily consisted of phenols and furans, whose alkyl side chains were short and few, mainly existing in the form of multiple methyl groups. The Asp-product produced smaller aromatic ring fragments, more aromatic hydrocarbons and less phenolic and non-phenolic oxygenated compounds than Asp-feed at the same pyrolysis temperatures • The evolution of polar functional groups in oxygen-enriched asphaltenes during hydrotreating was explored systematically. • The composition and structure of coal tar asphaltenes before and after HDT were studied by the multi-step Py-GC/MS method. • The OH-OH and OH-ether O were the major hydrogen bonds in coal tar asphaltenes. [ABSTRACT FROM AUTHOR]

Three distinct 3D Co(II) coordination polymers have been prepared based on Co(OAc) 2 and 5-methylnicotinate ligand (L-CH 3 ) via different synthetic approaches, including layer diffusion, solvothermal synthesis, and ambient stirring method. Through the layer diffusion method, a 3D framework {[Co(L-CH 3 ) 2 (H 2 O) 0.5 ](CH 3 OH) 1.25 } n ( 1 ) can be obtained, which displays a 4-connect (6 6 ) dia topological network. Employment of solvothermal synthesis affords another 3D framework {[Co 2 (L-CH 3 ) 4 (H 2 O)](H 2 O)} n ( 2 ), which shows a 5-connected (4 4 · 6 6 ) noz topology. {[Co(L-CH 3 ) 2 (H 2 O) 2 ](H 2 O)} n ( 3 ) can be produced from the ambient stirring method, featuring the 4-connected (4 2 · 6 4 ) lvt topology. These results demonstrate that fine-tunning on the diverse coordination motifs of 1 – 3 can be readily achieved by selecting proper synthetic approaches. In addition, thermal stability property of these complexes is also studied. [ABSTRACT FROM AUTHOR]

Understanding the structure and propertiesof cyclohexoxy radicaland its substitutes is important because of their presence in combustionprocesses, in atmospheric chemistry, and as intermediates in the hydrocarbonreactions. In this work, jet-cooled laser-induced fluorescence (LIF)spectra of five dimethyl substituted cyclohexoxy radicals are obtainedfor the first time. The correlation between the spectral variationsand the radical structural changes is studied with the assistanceof theoretical calculations at the B3LYP/6-31+G(d) and CASSCF/6-31+G(d)levels. The results show that the spectral characters of the dimethylcyclohexoxyradicals and their dissociation kinetics are predominantly affectedby the methyl substitution position related to the C–O group.The spectral effect of the two methyl groups will add up if they locateon asymmetric carbons of the cyclohexoxy ring. Methyl substitutionon β carbon weakens the six-member ring of cyclohexoxy and resultsin unimolecular dissociation via β C–C bond cleavageon the methyl group side and forms vinoxy variants. This study clearlyshows that the LIF spectra can be used to identify cyclohexoxy andthe isomers of its methyl substitutes. The results will help to understandthe photochemistry of cyclic hydrocarbons in the atmospheric and combustionprocesses. [ABSTRACT FROM AUTHOR]

This paper focuses on the combustion chemistry of 2-methylfuran (2-MF), a potential biofuel, and it is built on the previous work of Tran et al. [Combust. Flame 161 (2014) 766]. In their work, they had combined detailed flame chemistry modeling with flame speciation data based on flame-sampling molecular beam mass spectrometry (MBMS) with electron ionization and gas chromatography with MS detection. In this work, we significantly extend those previous studies by in-situ isomer-resolving species identification and quantification. Specifically, we have determined the detailed chemical structure of a premixed laminar 2-MF flame using flame-sampling high-resolution MBMS with synchrotron-generated vacuum-ultraviolet radiation. Mole fraction profiles of 60 intermediate, reactant, and product species were measured in order to assess the pollutant potential of this possible next-generation biofuel. Special emphasis is paid towards the fuel's ability to form aromatic and oxygenated intermediates during incomplete combustion processes, with the latter species representing a variety of different classes including alcohols, ethers, enols, ketones, aldehydes, acids, and ketenes. Whenever possible the experimental data are compared to the results of model calculations using the 2-MF combustion chemistry model of Tran et al., but it should be noted that many newly detected species are not included in the calculations. The experimental data presented in this work provides guidance towards to development of a next-generation 2-MF combustion chemistry model. [ABSTRACT FROM AUTHOR]

Polystyrene and poly(4-methylstyrene) have very similar chemical structures with the only differences being the para methyl group of poly(4-methylstyrene). This methyl group is susceptible to oxidation at elevated temperatures. Here we demonstrate that it is possible to introduce oxidative cross-links to poly(4-methylstyrene), via the para methyl group, by thermal oxidative treatment at 230 °C, 250 °C and 270 °C in the absence of catalyst, leading to a material with markedly modified thermal degradation chemistry. Thermal gravimetric analysis and differential scanning calorimetry were used to characterise and compare untreated and post-oxidised materials and established that as the temperature of pre-treatment was increased, the subsequent thermal stability of the material increased. FTIR, NMR and microanalysis indicated that after the thermal oxidative pre-treatment ether cross-links are present alongside new oxygen containing functional groups such as aldehydes, carboxylic acids and hydroxyl groups. Finally, data obtained from pyrolysis combustion flow calorimetry confirmed that as the number of oxidative cross-links increase, a reduction in the polymer's flammability as assessed by heat release data is observed. [ABSTRACT FROM AUTHOR]

Reaction of aryl- and benzylsulfanopyridinium amidates bearing a methyl group in position 6 with 2 equiv of diphenylketene afforded a spiro-fused ring system: azoniabenzo[de]fluorine. By use of an excess amount of ketene, a distinct reaction was observed via which a 1H-pyrrolo[3,2-b]pyridin-2(3H)-one derivative was furnished. The structure of the tetracyclic spiro-fused ring system was unambiguously confirmed by X-ray diffraction, and its formation was rationalized by DFT calculations. [ABSTRACT FROM AUTHOR]

By using simple and readily available DMSO as a convenient and environmentally friendly source of sulfur, a practical approach for the Pd-catalyzed decarboxylative methylthiolation of 2-nitrobenzoic acids was developed. A range of substituents on the aryl group of the ortho-nitrobenzoic acid were compatible with this process. [ABSTRACT FROM AUTHOR]

A series of propargyl acetates were prepared and used as propargyl electrophiles for coupling reactions with trimethylaluminum. The simple catalytic system of palladium(II) acetate (1 mol-%) and tri( o-tolyl)phosphine (2 mol-%) worked efficiently for a wide variety of aromatic and aliphatic propargyl acetates, producing the substituted allenes in good to excellent yields of up to 94 % in tetrahydrofuran. The process was simple and easily performed, and it provides an efficient method for the synthesis of substituted allene derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed. [ABSTRACT FROM AUTHOR]

Benzene, toluene, and xylene (BTX) are volatile aromatic compounds used in industries, however, they are hazardous when released into the environment. BTX degradation by Aspergillus niger cells combined with semiconducting zinc sulfide (ZnS) nanoparticles was explored in batch systems. Experiments were conducted individually for benzene, toluene, and xylene as well as in binary and trinary mixtures using A. niger cells-ZnS nanobiohybrids. The mechanism governing the removal of BTX by both A. niger cells and A. niger cells-ZnS nanobiohybrids were elucidated. Complete BTX degradation was achieved in 75 min and 60 min, respectively, by nanobiohybrids composed of chemical and biological ZnS nanoparticles in the presence of UV-A light at 1.83 * 1018 photons/second and 1.68 * 1018 photons/second, respectively. The removal efficiency was in the order of the molecular weight for A. niger cells, whereas for the light-driven A. niger -ZnS nanobiohybrids, the removal efficiency was according to the methyl group number. Further, the respiratory coefficient and volumetric mass transfer coefficient (Ka) values are higher for A. niger cells compared to the light-driven A. niger -ZnS nanobiohybrids. [Display omitted] • Removal efficiency of BTX hydrocarbons enhanced in the presence of light driven Aspergillus niger ZnS nanobiohybrids. • 100% efficiency achieved in 75 min and 60 min with chemical and biological ZnS nanobiohybrids, respectively. • Respiratory coefficient values were higher for Aspergillus niger ZnS nanobiohybrids in the presence of light. • Degradation mechanisms for benzene, toluene and p -xylene proposed [ABSTRACT FROM AUTHOR]

Highlights: [•] C2H5SH is selectively converted into H2S and C2H4 over protonic zeolites. [•] The reaction rate was proved to follow a first order law. [•] Catalyst lifetime measured at 823K is more than 70h of time-on-stream with a H-ZSM-5(15) catalyst. [•] C2H5SH and CH3SH mixtures are selectively converted into H2S, C2H4 and CH4 over H-ZSM-5(15). [•] The coke production significantly decreases in the presence of water. [Copyright &y& Elsevier]

A strategy to introduce the SCF3 group through the CuI-promoted reaction of diazo compounds with the nucleophilic AgSCF3 trifluoromethylthiolation reagent was developed. Various diazo compounds were smoothly converted under mild conditions to form the C(sp3)-SCF3 bond. Mechanistically, migratory insertion of SCF3-bearing Cu carbene intermediates is involved in this transformation. [ABSTRACT FROM AUTHOR]

A densityfunctional theory (DFT) study was performed to understandthe factors that control the reactivity of bipyridine (bpy)-ligatedRh(III) methyl complexes toward nucleophiles to produce functionalizedmethane and Rh(I) complexes. The effect of the structure of the complex,the nucleophile, the identity of the ancillary ligand, the electronicproperties of the bipyridine ligand, and the identity of the metalwere considered. Many similarities were found between the reactionof Rh(III) methyl complexes supported by bipyridyl ligands and classicorganic SN2 reactions, including a strong dependence ofthe reaction on the nucleophile identity and modifications to thecomplex that facilitate rhodium as a leaving group. Using these concepts,a comparison of reductive functionalization of Rh(III) alkyl complexessupported by porphyrin versus two bipyridyl ligands was made, andmodifications that could lead to more active complexes were proposed. [ABSTRACT FROM AUTHOR]

The intramolecular dehydrogenative amidation of aliphatic amides, directed by a bidentate ligand, was developed using a copper-catalyzed sp3 CH bond functionalization process. The reaction favors predominantly the CH bonds of β-methyl groups over the unactivated methylene CH bonds. Moreover, a preference for activating sp3 CH bonds of β-methyl groups, via a five-membered ring intermediate, over the aromatic sp2 CH bonds was also observed in the cyclometalation step. Additionally, sp3 CH bonds of unactivated secondary sp3 CH bonds could be functionalized by favoring the ring carbon atoms over the linear carbon atoms. [ABSTRACT FROM AUTHOR]

Abstract: This work investigated the support effect on the deoxygenation of methyl laurate to C11 and C12 hydrocarbons over nickel phosphide catalysts. By the H2-TPR method from the precursors with Ni/P ratio of 1.0, Ni2P was produced on SiO2, CeO2, TiO2 and SAPO-11, while Ni3P and Ni12P5 were formed on γ-Al2O3, and Ni12P5 and Ni2P were formed on HY. Ni2P/SiO2 had lower electron density of Ni site than other catalysts, where either there were the Ni3P and Ni12P5 phases or there was the electron transfer from reduced CeO2 or TiO2 to Ni2P. At 573–613K and 3.0MPa, the conversion of methyl laurate and the selectivity to C11 and C12 hydrocarbons tended to decrease in the sequence of Ni2P/SiO2 >Ni3P-Ni12P5/Al2O3 >Ni2P/TiO2 >Ni2P/SAPO-11>Ni2P-Ni12P5/HY>Ni2P/CeO2, whereas the C11/C12 molar ratio followed in the order of Ni2P/CeO2 >Ni3P-Ni12P5/Al2O3 >Ni2P/SiO2 >Ni2P/SAPO-11>Ni2P/TiO2 >Ni2P-Ni12P5/HY. The effect of supports mainly results from their acidity and reducibility. The catalyst activity, the selectivity to hydrocarbons and the deoxygenation pathway are correlated with the surface density of Ni site, the electron property of Ni site, the Ni2P crystallite size and the synergism between the Ni site and the acid site or the oxygen vacancy. [Copyright &y& Elsevier]

A novel palladium-catalyzed approach to 2-(aminomethyl)indoles from 3-(o-trifluoroacetamidoaryl)-1-propargylic alcohols and amines has been developed. [ABSTRACT FROM AUTHOR]

Highlights: [•] The activity followed the order Ni2P>MoP >CoP-Co2P>WP>Fe2P-FeP. [•] The activity followed the sequence Ni≈Ni2P>Ni12P5 >Ni3P. [•] Ni, Co and Fe phosphides mainly gave C11 products, MoP and WP mainly gave C12 ones. [•] MoP, WP and Fe2P-FeP also yielded alkenes and iso-alkanes apart from n-alkanes. [•] Metal electron property and Brönsted acidity determine activity and mechanism. [Copyright &y& Elsevier]

Thephysical properties of direct sugar to hydrocarbon diesel (DSH-76)and several binary mixtures of n-hexadecane and 2,2,4,6,6-pentamethylheptanewere measured in this work. The density and viscosity were measuredat temperatures ranging from (293.15 to 393.15) K, and the pure componentvalues fell within the range of previously reported values. Speedof sound data at temperatures ranging from (293.15 to 323.15) K increasedfrom (1089 to 1357) m·s–1. The bulk moduluswas calculated from the density and speed of sound data, and its valuesranged from (858 to 1425) MPa. Flash point values ranged from (318to 408) K, and the surface tension values ranged from (21.8 to 27.3)mN·m–1. The values of density, viscosity, speedof sound, bulk modulus, flash point (378 K), and surface tension (25.0mN·m–1) for the DSH-76 fell within the rangeof values measured for the binary mixtures of n-hexadecaneand 2,2,4,6,6-pentamethylheptane. These data suggest that a binarymixture of n-hexadecane and 2,2,4,6,6-pentamethylheptanemay be a suitable surrogate for renewable fuels such as DSH-76. [ABSTRACT FROM AUTHOR]