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In this study, we explored a method to distinguish between both enolizable regions of unsymmetrical 2,3‐diketones in organocatalytic domino reactions involving nitroalkenes. The selective formation of an enamine from only one side of the molecule was made possible by the use of optically pure 2‐(trifluoromethyl)pyrrolidine. This catalyst, remarkably enhancing the reaction, owes its efficacy to a unique interplay between basicity and nucleophilicity. These features caused the enolization of the substrate at the second possible site to be omitted. The approach resulted in excellent regio‐ diastereo‐ and enantioselectivity (91–99 % ee) across various nitroalkenes, leading to the synthesis of novel cyclopentanone derivatives with three contiguous stereogenic center. [ABSTRACT FROM AUTHOR]

In this article, 1-(4-ethylphenyl)-nonane-1,3-dione (0206) was prepared by Claisen condensation. By mixing 0206, chelate, and base oil in a ratio of 3.2:4.8:2, a diketone lubricant (PAO=14 (20%)) that can achieve superlubricity was prepared and applied to bearing lubrication experiments. The experimental results show that when the bearing was lubricated by base oil, the friction coefficient (COF) and temperature rise decreased with the decrease of the viscosity of PAO. When PAO=14 (20%) was used as the lubricant, the COF of the bearing was the lowest (0.001), and the wear morphology was comparable to that of the bearing lubricated with commercial lubricant. Compared with the base oil with the same viscosity, it is found that the COF and temperature rise of the bearing lubricated by PAO=14 (20%) were lower under any experimental conditions. And when the amount of lubricant added was 10 µL, the COF of the bearing lubricated by PAO=14 (20%) reached a very low value (0.0004). Bearing ball surface analysis identified the formation of diketone adsorption films. Combined with the previous PAO=14 (20%) superlubricity mechanism, it was considered that the occurrence of tribochemical reaction and the bearing effect of chelates were the main reasons for the existence of ultra-low friction coefficient and low wear. In addition, when there were polar molecules in the lubricant, they were adsorbed on the metal surface through tribochemical reactions, resulting in many irregular pits on the surface. [ABSTRACT FROM AUTHOR]

1-(4-ethylphenyl)-nonane-1,3-dione (0206) is an oil-soluble liquid molecule with rod-like structure. In this study, the chelate (0206-Fe) with octahedral structure was prepared by the reaction of ferric chloride and 1,3-diketone. The experimental results show that when using 0206 and a mixed solution containing 60% 0206-Fe and 40% 0206 (0206-Fe(60%)) as lubricants of the steel friction pairs, superlubricity can be achieved (0.007, 0.006). But their wear scar diameters (WSD) were very large (532 µm, 370 µm), which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction pairs. When 0206-Fe(60%) was mixed with PAO6, it was found that the friction coefficient (COF) decreased with increase of 0206-Fe(60%) in the solution. When the ratio of 0206-Fe(60%) to PAO6 was 8:2 (PAO6(20%)), it exhibited better comprehensive tribological properties (232.3 MPa). Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased WSD. Considering the COF, contact pressure, and running-in time, it was found that the mixed lubricant (Oil3(20%)) prepared by the base oil with a viscosity of 19.7 mPa·s (Oil3) and 0206-Fe(60%) exhibited the best tribological properties (0.007, 161.4 MPa, 3,100 s). [ABSTRACT FROM AUTHOR]

Abstract 1-(4-ethylphenyl)-nonane-1,3-dione (0206) is an oil-soluble liquid molecule with rod-like structure. In this study, the chelate (0206-Fe) with octahedral structure was prepared by the reaction of ferric chloride and 1,3-diketone. The experimental results show that when using 0206 and a mixed solution containing 60% 0206-Fe and 40% 0206 (0206-Fe(60%)) as lubricants of the steel friction pairs, superlubricity can be achieved (0.007, 0.006). But their wear scar diameters (WSD) were very large (532 µm, 370 µm), which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction pairs. When 0206-Fe(60%) was mixed with PAO6, it was found that the friction coefficient (COF) decreased with increase of 0206-Fe(60%) in the solution. When the ratio of 0206-Fe(60%) to PAO6 was 8:2 (PAO6(20%)), it exhibited better comprehensive tribological properties (232.3 MPa). Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased WSD. Considering the COF, contact pressure, and running-in time, it was found that the mixed lubricant (Oil3(20%)) prepared by the base oil with a viscosity of 19.7 mPa·s (Oil3) and 0206-Fe(60%) exhibited the best tribological properties (0.007, 161.4 MPa, 3,100 s).

Intramolecular hydrogen bonding has a significant effect on the radiolytic transformations of β-diketones. Using the radiolysis of acetylacetone as an example, it has been shown that a hydrogen bond between the hydroxyl and carbonyl in an enol prevents proton transfer from the primary radical cation to the neighboring molecule. As a result, the radiolytic formation of a keto alcohol (4-hydroxy-2-pentanone) was not observed at room temperature, but it was effective under boiling conditions. The intramolecular hydrogen bond contributed to a significant structural stress in the radical cation, which increased the yield of C–OH bond cleavage and the inhomogeneous formation of acetate (4-oxopent-2-en-2-yl acetate) under normal conditions. [ABSTRACT FROM AUTHOR]

Achievement of steady and reliable super-low friction at the steel/steel contact interface, one of the most tribological systems applied for mechanical moving parts, is of importance for prolonging machine lifetime and reducing energy consumption. Here we reported that the superlubricity performance of the steel/steel sliding interface lubricated with tiny amounts of diketone solution strongly depends on the oxygen content in surrounding environment. The increase of oxygen not only significantly shortens the initial running-in time but also further reduces the stable coefficient of friction in superlubricity stage due to the enhancement of tribochemical reactions. On the one hand, more severe oxidation wear occurring at higher oxygen content facilitates material removal of the contact interface, lowering the contact pressure and the corresponding initial friction. On the other hand, the growth of iron ions during the shear process in high oxygen environment promotes the formation of chelate which acted as an effective lubricated film chemisorbed at the steel/steel friction interface to further lower the interfacial friction. The results provide a new opportunity to further optimize the tribological performance of diketone superlubricity system, especially towards the lubrication of mechanical engineering materials. [ABSTRACT FROM AUTHOR]

Main conclusion: The alpine meadow plants showed great intra- and inter-genera variations of chemical profiles of cuticular waxes. Developing an understanding of wax structure-function relationships that will help us tackle global climate change requires a detailed understanding of plant wax chemistry. The goal in this study was to provide a catalog of wax structures, abundances, and compositions on alpine meadow plants. Here, leaf waxes from 33 plant species belonging to 11 families were sampled from alpine meadows of the east side of the Qinghai-Tibet Plateau. Across these species, total wax coverage varied from 2.30 μg cm−2 to 40.70 μg cm−2, showing variation both within as well as between genera and suggesting that wax variation is subject to both environmental and genetic effects. Across all wax samples, more than 140 wax compounds belonging to 13 wax compound classes were identified, including both ubiquitous wax compounds and lineage-specific compounds. Among the ubiquitous compounds (primary alcohols, alkyl esters, aldehydes, alkanes, and fatty acids), chain length profiles across a wide range of species point to key differences in the chain length specificity of alcohol and alkane formation machinery. The lineage-specific wax compound classes (diols, secondary alcohols, lactones, iso-alkanes, alkyl resorcinols, phenylethyl esters, cinnamate esters, alkyl benzoates, and triterpenoids) nearly all consisted of isomers with varying chain lengths or functional group positions, making the diversity of specialized wax compounds immense. The comparison of species relationships between chemical data and genetic data highlighted the importance of inferring phylogenetic relationships from data sets that contain a large number of variables that do not respond to environmental stimuli. [ABSTRACT FROM AUTHOR]

Abstract Achievement of steady and reliable super-low friction at the steel/steel contact interface, one of the most tribological systems applied for mechanical moving parts, is of importance for prolonging machine lifetime and reducing energy consumption. Here we reported that the superlubricity performance of the steel/steel sliding interface lubricated with tiny amounts of diketone solution strongly depends on the oxygen content in surrounding environment. The increase of oxygen not only significantly shortens the initial running-in time but also further reduces the stable coefficient of friction in superlubricity stage due to the enhancement of tribochemical reactions. On the one hand, more severe oxidation wear occurring at higher oxygen content facilitates material removal of the contact interface, lowering the contact pressure and the corresponding initial friction. On the other hand, the growth of iron ions during the shear process in high oxygen environment promotes the formation of chelate which acted as an effective lubricated film chemisorbed at the steel/steel friction interface to further lower the interfacial friction. The results provide a new opportunity to further optimize the tribological performance of diketone superlubricity system, especially towards the lubrication of mechanical engineering materials.

Herein, the rational design of an enaminone compound is reported which can be easily and conveniently designed and obtained via the reaction of amine and diketone. The dynamic enaminoneamide structure is formed via the reaction between isocyanate and enaminone in fabricating a novel dynamic crosslinked polyurethane. The new kind of polyurethane can be efficiently recycled via the shifting between crosslinked structure and oligomer for the reversible dissociation of the enaminoneamide structure. Besides remolding itself via the thermal treatment, oligomers liberated from recycled‐polyurethane can directly take part in constructing a new polyurethane without further purification. Therefore, the recyclability of this polyurethane shows high‐value characteristics. The ease with which polyurethane can be produced, used, recycled, and reused without losing value offers a new green solution in designing sustainable polymer materials with a high economic value and a minimal environmental burden. [ABSTRACT FROM AUTHOR]

• Photo-redox of nine oxyanions by dicarbonyl compounds was explored. • A structure-activity relationship model applicable to oxyanions was established. • A correlation network was constructed for the photochemistry of small molecules. • The photochemical behaviors of small molecules are predictable. • The network offers insights into the roles of small molecules in chemical contexts. Small molecules, including natural metabolites, organic matter decomposition products, and engineered oxidation byproducts, are widespread in aquatic environment. However, the limited understanding of the photochemical interactions of these small molecules with water pollutants hampers the development of effective environmental protection strategies. This study explores the structural features governing the photochemical transformation of toxic oxyanions by α - and β -dicarbonyl compounds. By integrating experimental observations with quantum chemical calculations, a robust correlation network was constructed. The correlation network reveals that the reactivity of small organic molecules with oxyanions could be quantitively predicted by their intrinsic properties, such as electronic transition energy, bond dissociation energy, molecular softness, molecular orbital gap, atomic charge, and molecular surface local ionization energy. This network maps the relationship between the molecular architecture of chemicals and their photochemical behaviors. This perspective offers fresh insights into the photochemical behaviors of small molecules in diverse environmental and chemical contexts and are helpful for developing advanced water treatment strategies toward a sustainable future. [Display omitted] [ABSTRACT FROM AUTHOR]

Some novel phosphorus compounds of types 1,2-benzoxaphosphinines, phospholo-[3,4-b][1]benzofuran, and chromonyl/coumarinyl/indenonyl phosphonates were achieved. The methodology depended on reaction of 1-(2-hydroxyphenyl)-3-phenylpropane-1,3-dione (1) with diethyl phosphite in the absence and presence of electrophilic reagent. Reaction of substrate 1 with diethyl phosphite in the presence of a base afforded 3-benzoyl-4-hydroxy-2-oxido-2H-1,2-benzoxaphosphinine (2), white its reaction with diethyl phosphite in the presence of ammonia, formaldehyde and chloroacetyl chloride under basic conditions gave the corresponding 4-ethoxy-4-oxido-2-phenyl-3,4-dihydro[1,2]benzoxaphosphinino[3,4-b] pyrrole (6) and 1-benzoyl-2-ethoxy-3-hydroxy-2-oxido-2H-phospholo[3,4-b][1]benzofuran (7), respectively. In addition, treatment of compound 1 with diethyl phosphite in the presence of DMFDMA, ethyl chloroacetate and oxalyl chloride under the same conditions led to the formation of chromonyl/coumarinyl/indenonyl phosphonates 3, 8, and 10, respectively, in moderate yields. The reaction mechanisms for the formation of these products were presented and explained. The molecular structures of products were deduced by spectral and analytical tools. The antimicrobial activity for the novel products were evaluated. The antimicrobial results were supported by SwissADME server based in silico computations. Both products 6 and 10 showed excellent antimicrobial properties. [ABSTRACT FROM AUTHOR]

High‐performance and recyclable high valence oxides of ruthenium catalyst had been released safely from commercially available ruthenium carbon catalyst in situ. They could selectively oxidize C=C bonds to corresponding aldehydes or ketones in 78%–99% yields and C ≡ C bonds to α‐diketones in 93%–99% yields. The cheap availability, recyclability, safety, and low toxicity of ruthenium carbon might endow the catalyst with great potential in industrial scale unsaturated bond oxidation cleavage applications. [ABSTRACT FROM AUTHOR]

Known 1,6-di(thiophen-2-yl)hexane-1,6-dione (2) and novel 1,7-di(thiophen-2-yl)heptane-1,7-dione (4) were obtained from the reactions of thiophene with the corresponding diacyl chlorides. Furthermore, compounds with furan and pyrrole units in place of thiophene units in compound 2 were obtained in the same way. Bromination of 2 and 4 gave bromides regioselectively. The reaction of each of the compounds 2 and 4 in HOAc medium yielded cyclocondensation products. In total, four known and eleven novel compounds were synthesized. [ABSTRACT FROM AUTHOR]

In addition to vaccines, antiviral drugs are essential in order to suppress COVID-19. Although some inhibitor candidates have been determined to target the SARS-CoV-2 protein, there is still an urgent need to continue researching novel inhibitors of the SARS-CoV-2 main protease 'Omicron P132H', a protein that has recently been discovered. In the present study, in the search for therapeutic alternatives to treat COVID-19 and its recent variants, we conducted a structure-based virtual screening using docking studies for a new series of pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives 5–13, which were synthesized from the condensation reaction of pyrazolopyrimidinone-hydrazide (4) with a series of electrophiles. Some significant ADMET predictions–in addition to the docking results–were obtained based on the types of interactions formed and the binding energy values were compared to the reference anti- SARS-CoV-2 redocked drug nirmatrelvir. [ABSTRACT FROM AUTHOR]

α-Diketones such as diacetyl (2,3-butanedione) and 2,3-pentanedione are generated during the roasting and fermentation of foods and are also used as flavoring compounds. Exposure to these compounds has been associated with obliterative bronchiolitis in workers. We report indoor air concentrations of diacetyl and 2,3-pentanedione, as well as acetoin (3-hydroxy-2-butanone), in several small coffee roasteries and breweries using standard integrated air sampling sorbent tubes followed by gas chromatography tandem mass spectrometry as well as the first use of on-site continuous real-time proton-transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS). Diacetyl and 2,3-pentanedione were detected in most of the sorbent samples at concentrations between 0.02 and 8 ppbv, and in general were higher in coffee roasteries compared with breweries. Three integrated air samples, all from the barista area at one facility, exceeded the NIOSH recommended exposure limit (REL) of 5 ppbv for diacetyl. 2,3-Pentanedione concentrations in these three samples were greater than 50% of its REL, but did not exceed it. Acetoin, a precursor to diacetyl, was also detected at concentrations between 0.03 and 5 ppbv in most sorbent tube samples, with concentrations generally higher in breweries. PTR-ToF-MS measurements exhibited similar trends and provided continuous real-time volatile organic compound data that showed episodic excursions with peak concentrations of diacetyl and 2,3-pentanedione between 15 and 20 ppbv. Examination of the time series data identified specific activities associated with peak diketone emissions, including transfer of freshly roasted coffee beans to the cooling tray, or the opening of a brew kettle. Additional indoor air quality parameters including CO2, NO2, and PM2.5 were also assessed on-site. Airway inflammation was assessed in 19 workers before and after each work shift using online measurements of fractional exhaled nitric oxide (FENO). The pre-shift mean FENO was 3.7 (95% confidence interval: −3.6, 11.0) ppbv higher and the post-shift FENO was 7.1 (−1.9, 16.1) ppbv higher for workers at coffee roasteries compared with breweries. The cross-shift change in FENO was 3.4 (−2.8, 9.6) ppbv higher for workers at coffee roasteries compared with breweries. However, none of these differences were statistically significant, and the cross-shift change in FENO was not statistically different from zero for either group of workers. The findings from this pilot study demonstrate that α-diketones and related compounds are present in the indoor air of both breweries and coffee roasteries and may exceed health protective guidelines in coffee roasteries. Additional studies are required to fully characterize worker exposures in these settings and to identify specific work activities and processes associated with high exposures. Engineering controls, including targeted exhaust ventilation and the use of low-cost sensors, are recommended as an approach to protect workers from exposure to hazardous levels of α-diketones. [ABSTRACT FROM AUTHOR]

A highly efficient and catalyst-free protocol is reported for the synthesis of quinoxalines via the classical cyclocondensation reaction between aryldiamines and dicarbonyl compounds. Remarkably simple and green reaction conditions employing methanol as solvent afforded medium to excellent yield of quinoxalines after only one-minute reaction time at ambient temperature. The conditions allow at least 10 gram scale synthesis of quinoxalines and should be a preferred starting point for optimization and method of choice for applications in the synthetic community.

The title compound, C14H6F4O2, crystallizes with half of a molecule per asymmetric unit and exhibits bond lengths and angles typical of α-diketones. A network of C—H...F contacts and π–π stacking interactions is observed within the structure.

Condensation reactions of acetyl derivatives of thiochromane series with acetyl ether were studied. As a result of the reaction, it was found that acetylthiochromane compounds react with acetyl ether in the same way as aliphatic and aromatic ketones, and the reaction produces thiochromanoilacetones with good yields. [ABSTRACT FROM AUTHOR]

A new efficient one-pot procedure has been developed for the synthesis of 1-substituted partially hydrogenated 3-oxocycloalka[c]pyridine-4-carbonitriles by reaction of cyclopentanone or cyclohexanone with morpholine, acyl chloride, and cyanoacetamide. The proposed procedure is advantageous due to shorter reaction time and smaller amounts of the solvents and reactants. [ABSTRACT FROM AUTHOR]

The title compound, C14H6F4O2, crystallizes with half of a molecule per asymmetric unit and exhibits bond lengths and angles typical of diketones. A network of C-H=F contacts and stacking interactions is observed within the structure. [ABSTRACT FROM AUTHOR]

In addition to vaccines, antiviral drugs are essential in order to suppress COVID-19. Although some inhibitor candidates have been determined to target the SARS-CoV-2 protein, there is still an urgent need to continue researching novel inhibitors of the SARS-CoV-2 main protease ‘Omicron P132H’, a protein that has recently been discovered. In the present study, in the search for therapeutic alternatives to treat COVID-19 and its recent variants, we conducted a structure-based virtual screening using docking studies for a new series of pyrazolo[3,4-d]pyrimidin-4(5H)-one derivatives 5–13, which were synthesized from the condensation reaction of pyrazolopyrimidinone-hydrazide (4) with a series of electrophiles. Some significant ADMET predictions–in addition to the docking results–were obtained based on the types of interactions formed and the binding energy values were compared to the reference anti- SARS-CoV-2 redocked drug nirmatrelvir.

We report here an effective and atom‐economical method to synthesize enantiomerically enriched cyclic β‐amino alcohols via a rhodium‐catalyzed asymmetric cycloisomerization of 1,3‐diketones with keto‐vinylidenecyclopropanes. The reactions proceed through a Rh‐catalyzed transformation of keto‐vinylidenecyclopropanes via cleavage of the distal C−C bond of the three‐membered ring as a three‐carbon synthon, allowing the generation of a range of enantiomerically enriched cyclic β‐amino alcohols tethered to an alkene and an 1,3‐dione moiety in good yields with high ee values under mild conditions. Derivatizations including allylation of the functionalized β‐amino alcohols and subsequent RCM reaction as well as the preparation of a pyrazole derivative were carried out as well. [ABSTRACT FROM AUTHOR]

The synthesis of anti‐[1.1](2,17)(6,13)ferrocenophane‐1,12‐dione (2) is discussed. By addition of LiAlH4, NaBH4 or Wittig's reagent only one keto group reacted to give HO‐ or cC3H4‐functionalized [1.1](2,17)(6,13)ferrocenophan‐12‐hydroxy‐1‐one (3) and [1.1](2,17)(6,13)ferrocenophan‐12‐cyclopropane‐1‐one (4). Exchange of CO by CS groups is possible upon addition of Lawesson's reagent to 2 forming [1.1](2,17)(6,13)ferrocenophan‐1,12‐dithioketone (5). Theoretical studies confirm the different reactivities of the CO groups. Electrochemical studies on 2–5 showed separated reversible one‐electron events for 2–4 (125–925 mV) and an irreversible one for 5. The ferrocenyls in 4 are easier to oxidize, due to their higher electron‐richness. In 2 a larger redox separation comes about suggesting a stronger intermetallic interaction between FeII/FeIII in the mixed‐valent species. In situ UV‐vis/NIR studies confirm that 2 is a weak coupled class II system according to the classification of Robin and Day. Compounds 3 and 4 display electrostatic interactions among the ferrocenyls as oxidation progresses. [ABSTRACT FROM AUTHOR]

Photochemical transformation of iron plays crucial roles in the geochemical evolution of marine, terrestrial and atmospheric systems. In the present work, the photo-conversion of ferric iron and ferrous iron were studied in the presence of four naturally abundant organic compounds (OCs): two carboxylic acids [oxalic acid, salicylic acid] and two diketones [acetylacetone (Hacac), diacetyl]. The key finding is that the two diketones significantly accelerated both the photo-reduction of Fe(III) and the photo-oxidation of Fe(II) in acidic solutions. The quantum yields (Φ) of [Fe(acac)]2+ and Fe(III)-salicylate at 254 nm were estimated to be 0.23 and 0.02, respectively. The formation of photoactive Fe(III)-OC complexes accounted for the changed photo-steady state of iron but was not the exclusive factor. The enhanced consumption of dissolved oxygen (6 and 16 times in Fe(III) and Fe(II)-initiated systems) was attributed to the effects of the nonchelating diacetyl on the photo redox cycling of iron. Although the photoactivity of Fe(III)-oxalate (Φ 254 nm = 1.25) was much higher than those of Fe(III)-acac and Fe(III)-salicylate, the effect of oxalate did not last, because oxalate was rapidly depleted in several minutes. The addition of the two diketones kept either the Fe(III)-initiated system or the Fe(II)-initiated system at the Fe(II) state for hours, which is of great environmental significance, because Fe(II) is more active in both engineered and natural environments. [ABSTRACT FROM AUTHOR]

A convenient heterogeneous continuous-flow procedure for the polarity reversal of aromatic α-diketones is presented. Propaedeutic batch experiments have been initially performed to select the optimal supported base capable to initiate the two electron-transfer process from the carbamoyl anion of the N,N-dimethylformamide (DMF) solvent to the α-diketone and generate the corresponding enediolate active species. After having identified the 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine on polystyrene (PS-BEMP) as the suitable base, packed-bed microreactors (pressure-resistant stainless-steel columns) have been fabricated and operated to accomplish the chemoselective synthesis of aroylated α-hydroxy ketones and 2-benzoyl-1,4-diones (benzoin- and Stetter-like products, respectively) with a good level of efficiency and with a long-term stability of the packing material (up to five days).

An asymmetric organocatalytic cascade reaction between cyclopentane-1,2-diones and alkylidene malononitriles affords highly substituted 4 H -pyrans in moderate to high enantiomeric excess. The selective reduction of a bridged double bond leads to the formation of cis -substituted cyclopentanone with three contiguous stereogenic centres. [ABSTRACT FROM AUTHOR]

Abstract This paper highlights the lubricating and film-forming behaviors of diketone and surface characteristics of tribopairs after the friction test. An ultralow friction coefficient of 0.007 is accomplished on steel surfaces with diketone. The existence of tribochemical adsorption films inside the wear track is directly measured and observed. Moreover, a well-developed conformal contact surface morphology is generated between two friction pairs, which can be helpful to the realization of ultralow friction on rough surfaces. In addition, the film thickness of diketone was detected using by relative optical interference intensity (ROII) under different rolling speeds. Present work reveals that diketone lubricant has a good lubricating performance on steel surfaces, and can be extended to applications with small loads. Graphical abstract Tribochemical adsorbed films are formed on steel surfaces lubricated with EPBD-0201. (a) XPS spectra of C 1s, (b) adsorption model of diketone molecule with iron ion, (c) molecular structure of chelate. Image 1 Highlights • Ultralow friction coefficient of 0.007 is achieved and keeps stable on steel surfaces lubricated with EPBD-0201. • Tribochemical reaction between diketone molecules and iron ions occurs and chemically adsorbed films are formed on rubbing surfaces. • A well-established conformal contact surface morphology between steel ball and disc is generated lubricated with EPBD-0201 during running-in process due to the tribochemical reaction. [ABSTRACT FROM AUTHOR]

Abstract In the present work, complex formation equilibria between copper(II) and 1,1,1-trifluoro-4-(2-methoxyphenyl)butan-2,4-dione (1) have been investigated by UV–vis spectroscopy in ethanol/0.01 M NEt 4 NO 3 as an ionic strength adjuster at 25 °C. The composition of the complex in solution was determined using Job's plot and molar ratio method. Four single crystals of copper complexes CuL 2 (DMF) (2), CuL 2 (3), CuL 2 (DMSO) 2 (4) and CuL 2 (DMSO) (5), which include the ligand molecules in the cis - and trans -conformations, respectively, were obtained. The complexes were characterized with FT-IR spectroscopy, elemental analysis, and X-ray crystallography. In the complexes 2 and 5, the copper atoms adopt distorted square pyramidal coordination polyhedra formed by oxygen atoms, whereas the geometry around the copper atom in the complexes 3 and 4 can be described as square planar and square bipyramidal, respectively. Cu O bond lengths were calculated within the density functional theory using two different functionals, viz., BP86 and B3LYP, in combinations with Ahlrichs and Pople basis sets to be compared with each other and with experimentally determined values. Compounds 1 – 4 were tested for their in vitro antimicrobial activity and found active to a variable extent. According to measured minimum inhibitory concentrations (MIC), the title complexes show comparable or higher activity against bacteria and yeast with respect to the free ligand. It was shown that the biological activity is induced by intact complexes and is not resulted from the complex decomposition into copper(II) ions and the free ligand. Graphical abstract Image 1 Highlights • The binding properties of the ligand 1 in solution and in solid were studied. • The DFT calculation for copper complexes were compared with X-Ray crystallography. • The copper(II) complexes are more bioactive than the initial ligand. [ABSTRACT FROM AUTHOR]

[Display omitted] • Acetoacetamide (CSD2) is used as a selective depressant to realize the flotation separation of sulfide minerals. • The collectorless flotation with only CSD2 reduces the cost and simplifies the process. • CSD2 can expand the recovery gaps between molybdenite and chalcopyrite, galena, and pyrite to 60–80%. • –C=O in CSD2 molecule realizes the stable adsorption onto the surfaces of chalcopyrite, galena and pyrite. • –NH 2 in CSD2 molecule bonds to S2– through hydrogen bonding, improving its selectivity and surface hydrophilicity. Molybdenite is usually associated with chalcopyrite and other sulfide minerals, which troubles the efficient utilization of Mo resources. Flotation using various surfactants is a key technology to solve the problem. In this work, acetoacetamide (CSD2) is used as a novel depressant to realize the selective separation of molybdenite from chalcopyrite, galena and pyrite. Any collector is unwanted for the flotation system using CSD2, which not only reduces the cost, but also simplifies the flotation process. Under the optimum and green flotation scheme ([CSD2] = 5 × 10−4 mol/L; the pulp pH = 7), CSD2 can expand the recovery gap between molybdenite and chalcopyrite (or galena or pyrite) to 60% ∼ 80%. The excellent and selective depression of CSD2 has been continued in the flotation systems of mixed minerals and grinding products of quaternary mineral mixtures (GPQMM), confirming the potential industrial application prospect. The selective depression of CSD2 is confirmed by Zeta potential and contact angle measurements. After being treated with CSD2, the Zeta potential and hydrophilicity of the surfaces of chalcopyrite, galena and pyrite have more obvious changes than those of molybdenite surface, meaning a stronger adsorption of CSD2. In addition, the selective depression mechanism of CSD2 is further investigated through Fourier Transform Infrared (FTIR) analysis, X-ray Photoelectron Spectroscopy (XPS) analysis and electrostatic potential surface (EPS). The stable adsorption of CSD2 onto the surfaces of chalcopyrite, galena and pyrite is realized through forming six-membered chelation rings by the bi-carbonyl groups (–C=O) in CSD2 molecules and the metal ions on the mineral surfaces. At the same time, the amino group (–NH 2) in CSD2 molecule also play an auxiliary role in the adsorption process through weak interaction. However, it is difficult to achieve an effective adsorption of CSD2 onto the surface of molybdenite, due to a lack of exposed metal ions. CSD2, as a high-performance depressant, has an industrial application potential in the collectorless/collector-free flotation separation of Mo-containing sulfide minerals. [ABSTRACT FROM AUTHOR]

A series of 2,2’-bipyrimidine-bridged dinuclear lanthanide complexes with the general formula [Ln(tmhd)3]2bpm (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionate, bpm = 2,2’-bipyrimidine, Ln = Gd(III), 1; Tb(III), 2; Dy(III), 3; Ho(III), 4 and Er(III), 5) has been synthesized and characterized. Sublimation of [Tb(tmhd)3]2bpm onto a Au(111) surface leads to the formation of a homogeneous film with hexagonal pattern, which was studied by scanning tunneling microscopy (STM). The bulk magnetic properties of all complexes have been studied comprehensively. The dynamic magnetic behavior of the Dy(III) and Er(III) compounds clearly exhibits single molecule magnet (SMM) characteristics with an energy barrier of 97 and 25 K, respectively. Moreover, micro-SQUID measurements on single crystals confirm their SMM behavior with the presence of hysteresis loops.

Claisen condensation of acetylferrocene (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 COCH 3 ) and methyl ether of cymantrenecarboxylic acid (CO) 3 Mn(η 5 -C 5 H 4 COOMe) results in β-diketone (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )-C(O)CH 2 C(O)-(η 5 -C 5 H 4 )Mn(CO) 3 ( I ) which reacts with hydrazine to form a heterometallic pyrazole (η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )-N 2 C 3 H 3 -(η 5 -C 5 H 4 )Mn(CO) 3 ( II ) or reacts with diiodo( p -cymene)ruthenium(II) dimer giving chelate β-ketoenolate complexes of ruthenium, ( p -cymene)RuI[(η 5 -C 5 H 5 )Fe(η 5 -C 5 H 4 )-C(O)CHC(O)-(η 5 -C 5 H 4 )Mn(CO) 3 ] ( III ). The structures of complexes I – III were determined by single crystal X-ray diffraction. Electrochemical properties were studied too. [ABSTRACT FROM AUTHOR]

A series of novel binuclear transition metal complexes was synthesized by reaction of a Schiff base ligand (1-Methyl-2-(2-oxo-1,2-dihydro-pyrimidin-4-ylimino)-propylideneamino-acetic acid) (LaH) derived from 4-amino-pyrimidine-2-one, diacetyl, glycine and corresponding chloride salt of Cu(II), Ni(II), Co(II) and Zn(II) metals in 1:1 (metal : ligand) molar ratio. The compounds were characterized by elemental analyses, molar conductance measurement, magnetic moment measurement and various spectral studies viz. IR, UV-visible, 1H-NMR, 13C-NMR, EPR and ESI-MS. Molar conductance measurement data revealed non-electrolytic nature of metal complexes. Electronic absorption spectral data, electronic paramagnetic resonance parameters and magnetic moment values revealed an octahedral geometry for binuclear metal complexes. Cyclic voltammetric study of Ni(II) complex shows a couple of one electron anodic responses near 0.70 V and 1.10 V. In vitro biological activity of Schiff base ligand and binuclear complexes has been checked against bacteria (Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Salmonella typhi) and fungi (Candida albicans and Candida parapsilosis) to assess their antibacterial and antifungal properties.