Aliphatic Carbonyl Compounds Research Articles

Defining a core breath profile for healthy, non-human primates

Non-human primates remain the most useful and reliable pre-clinical model for many human diseases. Primate breath profiles have previously distinguished healthy animals from diseased, including non-human primates. Breath collection is relatively non-invasive, so this motivated us to define a healthy baseline breath profile that could be used in studies evaluating disease, therapies, and vaccines in non-human primates. A pilot study, which enrolled 30 healthy macaques, was conducted. Macaque breath molecules were sampled into a Tedlar bag, concentrated onto a thermal desorption tube, then desorbed and analyzed by comprehensive two-dimensional gas chromatography-time of flight mass spectrometry. These breath samples contained 2,017 features, of which 113 molecules were present in all breath samples. The core breathprint was dominated by aliphatic hydrocarbons, aromatic compounds, and carbonyl compounds. The data were internally validated with additional breath samples from a subset of 19 of these non-human primates. A critical core consisting of 23 highly abundant and invariant molecules was identified as a pragmatic breathprint set, useful for future validation studies in healthy primates.

ATI Stabilized Germylene Cation as a Cyanosilylation Catalyst for Aldehydes and Ketones.

The aminotroponiminate (ATI) ligand stabilized germylene cation [(i-Bu)2ATIGe][B(C6F5)4] (2) is found to be an efficient low-valent main-group catalyst for the cyanosilylation of aldehydes and ketones (ATI=aminotroponiminate). It was synthesized by reacting [(i-Bu)2ATIGeCl] (1) with Na[B(C6F5)4]. The catalytic cyanosilylation of diverse aliphatic and aromatic carbonyl compounds (aldehydes and ketones) using 0.075-0.75 mol% of compound 2 was completed within 5-45 min. The catalytic efficiency seen with aliphatic aldehydes was around 15,800 h-1, making compound 2 a capable low-valent main-group catalyst for the aldehyde and ketone cyanosilylation reactions. Further, DFT calculations reveal a pronounced charge localization at the germanium atom of compound 2, leading to its superior catalytic performance.

Transfer hydrogenation of aldehydes and ketones with tetrahydroxydiboran in water by an amphiphilic resin-supported nano-palladium catalyst

Abstract We have developed a transfer hydrogenation of aldehydes and ketones with B2(OH)4 as a reductant and amphiphilic resin-dispersed palladium nanoparticles as a catalyst system in an aqueous medium, where water also serves as a hydrogen donor. A variety of aldehydes and ketones, including aliphatic carbonyl compounds, reacted to give the corresponding primary and secondary alcohols, respectively. The catalyst was recovered by filtration and reused 9 times without a significant loss of its catalytic activity.

Chemical Composition of Volatile and Extractive Components of Canary (Tenerife) Propolis.

The vegetation of the Canary Islands is characterized by a large number of endemic species confined to different altitudinal levels. It can be assumed that these circumstances determine the characteristic features of the chemical composition of local beekeeping products, including propolis. We report, for the first time, the chemical composition of propolis from Tenerife (Canary Islands). The volatile emissions of three propolis samples collected from different apiaries are represented by 162 C1-C20 compounds, of which 144 were identified using the HS-SPME/GC-MS technique. The main group of volatiles, consisting of 72 compounds, is formed by terpenoids, which account for 42-68% of the total ion current (TIC) of the chromatograms. The next most numerous groups are formed by C6-C17 alkanes and alkenes (6-32% TIC) and aliphatic C3-C11 carbonyl compounds (7-20% TIC). The volatile emissions also contain C1-C6 aliphatic acids and C2-C8 alcohols, as well as their esters. Peaks of 138 organic C3-C34 compounds were recorded in the chromatograms of the ether extracts of the studied propolis. Terpene compounds form the most numerous group, but their number and content in different samples is within very wide limits (9-63% TIC), which is probably due to the origin of the samples from apiaries located at different altitudes. A peculiarity of the chemical composition of the extractive substances is the almost complete absence of phenylcarboxylic acids and flavonoids, characteristic of Apis mellifera propolis from different regions of Eurasia and North America. Aromatic compounds of propolis from Tenerife are represented by a group of nine isomeric furofuranoid lignans, as well as alkyl- and alkenyl-substituted derivatives of salicylic acid and resorcinol.

Exploring the hidden treasures of Nitella hyalina: a comprehensive study on its biological compounds, nutritional profile, and unveiling its antimicrobial, antioxidative, and hypoglycemic properties.

Macroalgae has the potential to be a precious resource in food, pharmaceutical, and nutraceutical industries. Therefore, the present study was carried out to identify and quantify the phyco-chemicals and to assess the nutritional profile, antimicrobial, antioxidant, and anti-diabetic properties of Nitella hyalina extracts. Nutritional composition revealed0.05 ± 2.40% ash content, followed by crude protein (24.66 ± 0.95%), crude fat (17.66 ± 1.42%), crude fiber (2.17 ± 0.91%), moisture content (15.46 ± 0.48%) and calculated energy value (173.50 ± 2.90 Kcal/100g). 23 compounds were identified through GC-MS analysis in ethyl acetate extract, with primary compounds being Palmitic acid, methyl ester, (Z)-9-Hexadecenoic acid, methyl ester, and Methyl tetra decanoate. Whereas 15 compounds were identified in n-butanol extract, with the major compounds being Tetra decanoic acid, 9-hexadecanoic acid, Methyl pentopyranoside, and undecane. FT-IR spectroscopy confirmed the presence of alcoholic phenol, saturated aliphatic compounds, lipids, carboxylic acid, carbonyl, aromatic components, amine, alkyl halides, alkene, and halogen compounds. Moreover, n-butanol contains 1.663 ± 0.768mg GAE/g, of total phenolic contents (TPC,) and 2.050 ± 0.143 QE/g of total flavonoid contents (TFC), followed by ethyl acetate extract, i.e. 1.043 ± 0.961mg GAE/g and 1.730 ± 0.311mg QE/g respectively. Anti-radical scavenging effect in a range of 34.55-46.35% and 35.39-41.79% was measured for n-butanol and ethyl acetate extracts, respectively. Antimicrobial results declared that n-butanol extract had the highest growth inhibitory effect, followed by ethyl acetate extract. Pseudomonas aeruginosa was reported to be the most susceptible strain, followed by Staphylococcus aureus and Escherichia coli, while Candida albicans showed the least inhibition at all concentrations. In-vivo hypoglycemic study revealed that both extracts exhibited dose-dependent activity. Significant hypoglycemic activity was observed at a dose of 300mg/kg- 1 after 6h i.e. 241.50 ± 2.88, followed by doses of 200 and 100mg/kg- 1 (245.17 ± 3.43 and 250.67 ± 7.45, respectively) for n-butanol extract. In conclusion, the macroalgae demonstrated potency concerning antioxidant, antimicrobial, and hypoglycemic properties.

Nanosized Ti-Based Perovskite Oxides as Acid-Base Bifunctional Catalysts for Cyanosilylation of Carbonyl Compounds.

The development of effective solid acid-base bifunctional catalysts remains a challenge because of the difficulty associated with designing and controlling their active sites. In the present study, highly pure perovskite oxide nanoparticles with d0-transition-metal cations such as Ti4+, Zr4+, and Nb5+ as B-site elements were successfully synthesized by a sol-gel method using dicarboxylic acids. Moreover, the specific surface area of SrTiO3 was increased to 46 m2 g-1 by a simple procedure of changing the atmosphere from N2 to air during calcination of an amorphous precursor. The resultant SrTiO3 nanoparticles showed the highest catalytic activity for the cyanosilylation of acetophenone with trimethylsilyl cyanide (TMSCN) among the tested catalysts not subjected to a thermal pretreatment. Various aromatic and aliphatic carbonyl compounds were efficiently converted to the corresponding cyanohydrin silyl ethers in good-to-excellent yields. The present system was applicable to a larger-scale reaction of acetophenone with TMSCN (10 mmol scale), in which 2.06 g of the analytically pure corresponding product was isolated. In this case, the reaction rate was 8.4 mmol g-1 min-1, which is the highest rate among those reported for heterogeneous catalyst systems that do not involve a pretreatment. Mechanistic studies, including studies of the catalyst effect, Fourier transform infrared spectroscopy, and temperature-programmed desorption measurements using probe molecules such as pyridine, acetophenone, CO2, and CHCl3, and the poisoning effect of pyridine and acetic acid toward the cyanosilylation, revealed that moderate-strength acid and base sites present in moderate amounts on SrTiO3 most likely enable SrTiO3 to act as a bifunctional acid-base solid catalyst through cooperative activation of carbonyl compounds and TMSCN. This bifunctional catalysis through SrTiO3 resulted in high catalytic performance even without a heat pretreatment, in sharp contrast to the performance of basic MgO and acidic TiO2 catalysts.

Cyclic Acetals as Novel Long-Lasting Mosquito Repellents.

The use of skin repellents against hematophagous mosquitoes is an important personal protection practice wherever these insects are abundant and where they are vectors of diseases. DEET and Icaridin are the major synthetic insect repellents in commercial formulations and are considered the most effective. Here, we tested against the mosquito Aedes albopictus several cyclic hydroxyacetals synthesized by acetalization of commercially available aliphatic carbonyl compounds (ranging from C3 to C15) with either glycerol, 1,1,1-trismethyloletane, or 1,1,1-trismethylolpropane and compared their efficacy with commercial repellents. We found that several hydroxyacetals were comparable with DEET and Icaridin both in terms of the required dose and repellence duration, while a few performed better. For those most active, toxicity was investigated, finding that a few of them were less cytotoxic than DEET and less prone to permeate through cell layers. Therefore, such results indicate that novel safe mosquito repellents could be developed among cyclic hydroxyacetals.

Theoretical study on thermal decomposition mechanism of 1-nitroso-2-naphthol

1-nitroso-2-naphthol has thermal instability of thermal decomposition, spontaneous combustion and even explosion. Its thermal decomposition characteristics were tested by synchronous thermal analyzer (TGA/DSC); The activation energy of the thermal decomposition process was calculated by Kissinger method; The infrared absorption characteristic spectra of the gas products produced in the thermal decomposition process were measured by TGA/DSC-FTIR, and the thermal decomposition reaction process was speculated. The results show that the initial temperature (Tonset) of TGA exothermic decomposition of 1-nitroso-2 naphthol is between 129.01 and 155.69 °C, and the faster the heating rate(β), the higher the Tonset, but the faster the thermal decomposition rate, the greater the heat release and the worse the thermal stability. The activation energy (E) of the thermal decomposition process is 83.323 kJ/mol calculated by Kissinger method. The dynamic test results of TGA/DSC-FTIR show that the main reaction of 1-nitroso-2 naphthol during heating is intermolecular dehydration to form ether, and the secondary reaction is decomposition into aliphatic nitro compounds, carbonyl compounds and amines. Sodium hydroxide will reduce the thermal stability of 1-nitroso-2 naphthol. After adding sodium hydroxide, the thermal decomposition process of 1-nitroso-2 naphthol has changed. The main reaction is that 1-nitroso-2-naphthol reacts with sodium hydroxide to produce sodium nitrophenol, which is further decomposed into aliphatic nitro compounds. The research results have guiding significance for finding the reasonable conditions and temperature of 1-nitroso-2 naphthol during storage and transportation.

(Invited, Digital Presentation) Carbocation Generation By Organophotoredox Catalyzed Radical-Polar Crossover

Carbocation is one of the most common and reactive chemical species in organic chemistry, which has been broadly utilized for alkylation of various nucleophiles and rearrangement reaction. Conventionally, carbocation is generated from alkyl electrophiles or alkenes in the presence of strong Lewis acids and Brønsted acids, which narrows usable nucleophiles and coexistable functional groups. The requirement of strong acidic conditions would originate from the difficulty of two electron abstraction from carbocation precursors at once. Recently, to solve this problem, activation of substrates via single electron transfer was presented. Knowles and co-workers reported the carbocation generation from the mesolytic cleavage of alkoxyamine-derived radical cation, that is generated by a visible-light mediated photoredox catalysis. Although this protocol does not require the strong acids, the low accessibility of alkoxyamine substrates restricted the introducible alkyl groups. In this presentation, a new approach to catalytic generation of carbocation by a visible light-mediated organophotoredox catalysis is provided. We were interested in an organocatalysis merging with the radical-polar crossover (RPC) mechanism as an approach to non-acidic and catalytic generation of carbocations. Details of our scenario for the RPC are described in Figure. We selected N-Ph-benzo[b]phenothiazine (PTH) as a suitable organophotoredox RPC catalyst due to three features: excitation in the UV-visible area, high reduction potential and potential persistent properties of the corresponding radical cation. Aliphatic carboxylic acid-derived redox active esters were chosen as carbocation precursors due to the availability and the well-studied reactivity. The catalytic system is initiated by single electron transfer from a phenothiazine catalyst to a redox active ester under irradiation of a blue light-emitting diode (LED) to generate the radical cation form of the catalyst (A) and an alkyl radical (B). Then, recombination process between A and B affords an alkylsulfonium intermediate C, which acts as a carbocation equivalent. The carbocation equivalent was applied to alkylation of various nucleophiles and the semipinacol rearrangement reactions. First, the catalytic system was exploited to alkylation of various nucleophiles. After screening of reaction conditions, the combination of N-phenyl benzo[b]phenothiazine and lithium tetrafluoroborate was found to be effective in this alkylation protocol. Aliphatic alcohol, water, amide, thiol, fluoride anion and allylsilane could participate in this organophotoredox catalysis as nucleophiles. This protocol allowed to use secondary or tertiary aliphatic carboxylic acid-derived redox active esters as alkylating reagents, providing sterically hindered molecules with functional group compatibility.Subsequently, we applied the photochemically-generated carbocation equivalent to the semipinacol rearrangement reaction. Although the semipinacol rearrangement reaction has been utilized in key steps for construction of complex carbon frameworks in total synthesis of natural products, the conventional methods require specific design of the substrates and harsh reaction conditions to control the reactivity and regioselectivity. Since our method has the advantage of using carboxylic acids as the carbocation precursors, the substrates are easily synthesized from the corresponding enolate species derived from aliphatic carboxylic acids and carbonyl compounds. Then, we found the b-hydroxy redox active ester derivatives underwent the decarboxylative semipinacol rearrangement reaction, affording the complex carbonyl compounds. For example, the reaction with substrate prepared from aromatic aldehyde and secondary aliphatic carboxylic acid proceeded to give the aldehyde bearing an a-quaternary carbon center through migration of the aromatic ring. The reactions with cyclic ketone-derived substrates also occurred to furnish the ring expansion products. Figure 1

Advanced Insights into Catalytic and Structural Features of the Zinc‐Dependent Alcohol Dehydrogenase from Thauera aromatica

The asymmetric reduction of ketones to chiral hydroxyl compounds by alcohol dehydrogenases (ADHs) is an established strategy for the provision of valuable precursors for fine chemicals and pharmaceutics. However, most ADHs favor linear aliphatic and aromatic carbonyl compounds, and suitable biocatalysts with preference for cyclic ketones and diketones are still scarce. Among the few candidates, the alcohol dehydrogenase from Thauera aromatica (ThaADH) stands out with a high activity for the reduction of the cyclic α‐diketone 1,2‐cyclohexanedione to the corresponding α‐hydroxy ketone. This study elucidates catalytic and structural features of the enzyme. ThaADH showed a remarkable thermal and pH stability as well as stability in the presence of polar solvents. A thorough description of the substrate scope combined with the resolution and description of the crystal structure, demonstrated a strong preference of ThaADH for cyclic α‐substituted cyclohexanones, and indicated structural determinants responsible for the unique substrate acceptance.

Quality Assurance of commercial guacamoles preserved by high pressure processing versus conventional thermal processing

Guacamole sauce is getting blossoming popularity worldwide, which is commercialized in multiple formats with different preserving methods. Volatile composition and sensorial properties of commercial guacamoles preserved by high pressure processing (HPP) and by thermal process were analysed with quality discrimination purposes. Commercial HPP-guacamoles, whose intended shelf-life is around 1–3 weeks stored at 1–6 °C, exhibited higher quantities of aliphatic carbonyl and hydroxyl compounds such as hexanal and trans -2-hexanal, meanwhile canned guacamoles were characterized by the huge amount of terpenes and sesquiterpenes as well as the occurrence of furans. Chemical differences were well correlated with sensorial data whose PCA drove to the discrimination among both commercial guacamoles. Results revealed that commercial HPP-guacamoles were characterized by stem, vegetal, fresh, green, avocado, fruity, nutty and velvety features from the original product. Consequently, commercial fresh HPP-guacamoles resulted in a good sensorial balance between varietal features and new sensory notes being regarded as product of higher quality. • HPP and canned-guacamoles were compared based on volatile composition and sensorial analysis. • Both preservation methods lead to changes in chemical composition. • Chemical differences were well correlated to sensorial data of both type of guacamoles. • HPP-guacamoles presented distinctive characteristics more similar than those of original product.

Миколиз древесины, его продукты и их использование. IV. Компонентный состав микологически разрушенной древесины

The article is devoted to the study of the component composition of mycologically destroyed wood. As a result of wood mycolysis under the action of wood-destroying fungi enzymes, so-called «rot» is formed with a chemical composition different from healthy wood. It is noted that the «brown rot» of wood is enriched with lignin components of wood and «white rot» with carbohydrate components of wood. The results of analyses of ligno-carbohydrate complexes of spruce wood «brown rot», birch wood «white rot» and a group study of low-molecular compounds isolated by extraction methods with various solvents are presented. It is noted that the content of lignin in the sample of «brown rot» wood is four times higher than in the sample of «white rot». It is shown that birch wood with «white rot» is significantly enriched with cellulose. The chemical nature of some groups of extractive substances has been revealed. In the extracts of mycologically destroyed wood, substances of phenolic, alcoholic and quinone nature were found. The presence of derivatives of aromatic and aliphatic carbonyl and carboxyl compounds is noted. Among the products of mycolysis, carbohydrates, flavanoids and terpenoids have been identified. Based on the analysis, an assumption is made that mycologically destroyed wood contains a wide range of phenolic and carbohydrate compounds contained both in the original wood and in the spores and hyphae of wood-destroying fungi themselves. The idea is substantiated that the study of extractive substances of mycologically destroyed wood makes it possible to predict possible directions of the prospective use of this raw material for obtaining target products. This article is the fourth in the cycle «Wood mycolysis, its products and their use», the previous ones were published in the journal «Forestry Bulletin», 2020, v. 24, no. 2, 6; v. 25, no. 1.

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

Selective upgrading of biomass-derived benzylic ketones by (formic acid)–Pd/HPC–NH2 system with high efficiency under ambient conditions

SYNTHESIS POLYFLUORINE-CONTAINING OF MONO-, DI- , TRIPEROXIDES

During interaction aliphatic and aromatic fluorine-containing carbonyl compounds with hydrope-roxide tret-bytil 1- hydroxylperoxides is obtained, hydrocarbonic analogs of which, mainly are not unstable. Possibility of their extraction and further chemical transformation are discussing.

Real-Time Monitoring of Aqueous Organic Reduction Reactions Using Ex Situ Fiber Optic Raman Spectroscopy

Here, we demonstrate the use of Raman spectroscopy for real-time monitoring and analysis of the reduction of nitroarenes and ketones in an aqueous medium using an external fiber optic probe. In one case, the catalytic reduction of nitroarenes using hydrazine hydrate and a nickel boron composite catalyst was studied by monitoring the disappearance of the distinct nitro stretching frequency at 1350 cm–¹. Quantitative Raman spectroscopic techniques showed that the aqueous reduction reaction proceeds with pseudo-first-order kinetics. The biphasic reduction of cyclic ketones by aqueous dimethylamine borane (DMAB) was also examined. A nonpolar carbonyl compound and aqueous DMAB were mixed and an external Raman probe monitored the loss of the starting material via the carbonyl stretch at 1713 cm–¹ in the top organic phase. We also found that saturated aliphatic carbonyl compounds were reduced much faster than α,β-unsaturated and aromatic carbonyl compounds. Additionally, DMAB was found to be unreactive toward epoxides and esters, allowing for selective reduction of aliphatic ketones. Density functional theory analysis suggests that carbonyl reduction occurred through a dissociation mechanism followed by a concerted hydride transfer pathway.

Efficient catalytic transfer hydrogenation reactions of carbonyl compounds by Ni(II)-diphosphine complexes

The catalytic transfer hydrogenation reactions of a series of aromatic and aliphatic carbonyl compounds were investigated using divalent Ni(II)-diphosphine complexes, [L2NiCl2] (where L2 = 1,1-bis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,1-bis(diphenylphosphino)ferrocene (dppf), and N-butyl-N-(diphenylphosphino)-1,1-diphenylphosphinamine (dppba)). This is a single-step reaction in the presence of potassium hydroxide and isopropyl alcohol to afford the corresponding alcohols. This protocol tolerates other sensitive functional groups like olefinic double bonds and also achieves high chemoselectivity. All the reactions were monitored by GC and GC–MS. The plausible mechanism is also discussed. The method reported in the present article is simple, cost-effective, and provides excellent conversions. Nickel-diphosphine complexes appear as a potential alternative to expensive transition metal complexes.

Mammalian exocrine secretions XIX. Chemical characterization of the interdigital secretion of the Black Wildebeest, Connochaetes gnou.

Using gas chromatography (GC) in conjunction with electron impact mass spectrometry and retention-time comparison, 94 compounds, ranging from 2-methyl-2-propenal to octadecanoic acid, were identified in the interdigital secretions of male and female black wildebeests, Connochaetes gnou (also known as the white-tailed gnu). The constituents of these secretions belong to many different compound classes, including hydrocarbons, alcohols, aromatics and aliphatic carbonyl compounds including carboxylic acids as well as carboxylic acid esters. Relatively small quantitative differences were found between the male and female interdigital secretions. It was concluded that these compounds probably do not play a significant role in territorial marking or in chemical communication between males and females of the species, but they could be involved in preserving the remarkably strong attachment between members of social subgroups in black wildebeest populations.

Catalytic Generation and Use of Ketyl Radical from Unactivated Aliphatic Carbonyl Compounds.

Generation of a ketyl radical from unactivated aliphatic carbonyl compounds is an important strategy in organic synthesis. Herein, catalytic generation and use of a ketyl radical for the reductive coupling of aliphatic carbonyl compounds and styrenes by organic photoredox catalysis is described. The method is applicable to both aliphatic ketones and aldehydes to afford the corresponding tertiary and secondary alcohols in continuous flow and batch. Preliminary mechanistic investigation suggests the catalytic formation of a ketyl radical intermediate.

Hydrogenation of Carbonyl Compounds over Pd in Aqueous Phase Under Charged Conditions: Role of Organic Molecular Structure

Electrocatalytic hydrogenation (ECH) is a promising approach for energy conversion utilizing renewable electricity to transform biogenic carbon sources to more useful feedstocks. Carbonyl groups are one of the most abundant and highly reactive functionalities of bio-derived molecules. Recent studies of benzaldehyde ECH showed a higher activity of C-supported Pd compared to other metals, i.e., Pt, Rh, Ni. In the present study we explore this catalytic chemistry further, comparing the reduction of aromatic and aliphatic carbonyl compounds on Pd/C with the aim to understand the influence of molecular structure on the reaction pathways and selectivity in ECH. The experiments were conducted over the potential range of -0.1 VRHE to -0.3 VRHE at low temperatures and atmospheric pressure. The aromatic carbonyl compounds benzaldehyde, acetophenone, and furfural showed significant reactivity toward hydrogenation, whereas the aliphatic carbonyl compounds butyraldehyde and cyclohexanone exhibited small or negligible reduction rates. Under these conditions, the reactive carbonyls all reduced to alcohols without secondary products. The Figure demonstrates the result of the cathodic potential on the reduction of carbonyls. The H2 evolution reaction (HER) was the prevalent side reaction during ECH and increased exponentially with negative potential. Benzaldehyde reduction rates were highest and increase linearly, followed by acetophenone reduction rates, which plateaued at -0.2 VRHE. Furfural reduction rates increased exponentially with cathodic potential albeit with lower values than benzaldehyde and acetophenone. Rotating disk electrode (RDE) experiments showed that the presence of organic compounds affects charge transfer processes to an extent that is a function of the molecular structure. These results indicate a competitive adsorption of organic compounds and hydrogen on Pd and highlight the dependence of hydrogenation rates, HER rates and charge transfer on the molecular structure, which determines the adsorption strength of the organic molecules. TCH rates are plotted against their OCV values in the Figure, showing lower rates than ECH. This allows to conclude that an electrochemical mechanism is dominating the reaction under cathodic bias. The data agrees well with a kinetic model, where the first hydrogen addition (through a proton coupled electron transfer) is the rate determining step. This work helps to understand the influence of molecular structure on the rates of electrocatalytic hydrogenation of organic compounds and simultaneous H2 evolution. Our studies will enable predictive models - based on common principles in catalysis - to be applied to other metals and organic compounds. Figure 1

N-P-Zn-containing 2D supermolecular networks grown on MoS2 nanosheets for mechanical and flame-retardant reinforcements of polyacrylonitrile fiber

In this work, a novel sandwich-type hybrid denoted as MPZSN-MoS2 was constructed by the self-assembling of melamine, phytic acid and Zn2+ to grow 2D supermolecular networks (MPZSN) onto the surface of molybdenum disulfide (MoS2) nanosheet, which was applied in mechanical and flame-retardant reinforcements of polyacrylonitrile fiber. With the incorporation 2 wt% MPZSN-MoS2, the tensile strength and elongation at break of MPZSN-MoS2/PAN composite fiber were increased by 68.2% and 27.8% compared to pure PAN fiber, respectively. The initial thermal decomposition temperature (T−5%) of MPZSN-MoS2/PAN fiber was increased by 21 °C, suggesting the enhanced thermal stability. Importantly, the single MPZSN-MoS2/PAN composite fiber could not be ignited and exhibited noticeable char formation when directly exposed to a flame, while the pure PAN fiber caught fire immediately and burned out. Moreover, the peak heat release rate and total heat release of MPZSN-MoS2/PAN fiber were remarkably decreased by 49.9% and 38.1% in contrast to pure PAN fiber, indicating its superior fire performance. The gaseous and condensed analysis demonstrated that the addition of MPZSN-MoS2 hybrids inhibited the effusion of pyrolysis products, such as HCN, CO, aliphatic CH compounds, CC compounds and carbonyl compounds, and promoted the generation of graphitized protective char layer on the fiber surface. This work presents a facile strategy for the design of MoS2-based hybrids with multi-components, expanding their potential applications in polymer composites.