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International audience; The nanocrystalline hydroxyfluorapatite (HFA) was synthesized by mechanosynthesis with a planetary ball mill (PM200). The disc to jar speed ratio was constant (equal to 0.5). The effect of different milling parameters such as grinding duration, balls number's, initial powder mass and disc rotation speed were studied to apprehend their effects on both the process of grinding/mechanosynthesis and the synthesis of nanocrystalline HFA. Unlike previous studies in which milling parameters have been independently studied, the effects of these parameters on the phase contents were simultaneously studied. Abdellaoui's model was also introduced to analyse the physical milling parameters effect such as the injected shock power, the shock kinetic energy, the shock frequency and the cumulated kinetic energy on the microstructural properties and synthesized phases contents. The results predicted by the model were compared to experimental ones. This study showed that the optimal conditions for the synthesis of nanocrystalline HFA were reached when the mechanosynthesis was carried out with a speed of 450 rpm, 6 balls, 1.2 g of starting material and 24 h of grinding duration. X-ray diffraction characterization confirmed the purity phase of HFA nanocrystalline powders.

Metal–organic frameworks (MOFs) have attracted a special attention due to outstanding porosity, adjustable pore sizes, and huge opportunities in varying organic–inorganic compositions. Enormous studies conducted so far on MOFs indicate their high potential in catalysis, gas adsorption, drug delivery, water treatment, energy storage, among others. However, mass production of MOFs is still limited mainly due to the non-economic, non-green and complex synthesis methods. Mechanochemistry is an alternative solution for efficient and environmentally friendly syntheses of various MOFs. Fast and solvent-free or solvent-less mechanosynthesis seems to be a very powerful versatile method for obtaining these advanced porous materials. The mechanochemical concept was used for the preparation of various MOFs including the most popular structures: MOF-5, ZIF-8, HKUST-1, MIL-101, UiO-66. These MOFs feature high specific surface areas, comparable to those prepared by conventional solvent-based methods. Furthermore, mechanochemistry was successfully used for the synthesis of non-conventional multimetallic MOFs and previously unreported solid phases. This review shows the recent developments, challenges and perspectives of green synthesis of diverse MOF structures using mechanochemistry. Besides describing the mechanochemical synthesis of MOFs, some achievements in green applications are also summarized. Importantly, current trends in research suggests for further development of these fields i.e., harmful gas adsorption, water treatment, and energy storage.

BaZrO3-based materials have been intensively researched due to their potential application as high-temperature proton conductors in devices such as proton ceramic fuel cells (PCFCs), separation membranes and electrolysers. Nonetheless, their implementation in these devices has often been constrained due to their processing difficulties, namely the formation of Ba-deficient compositions, coexistence of separate perovskite phases or the formation of segregated phases of the acceptor dopant. In this context, the current article shows mechanosynthesis to be an efficient preparation method for Ba(Zr,Y)O3-δ materials, producing pure powders, containing nanometric crystallites, that offer good densification and grain growth. The phase formation, microstructure and electrical properties of the most promising BaZr1-yYyO3-δ compositions, with yttrium contents of y = 0.15 (BZY15) and y = 0.20 (BZY20) are investigated and compared with literature data of materials made by other processing routes. Such a comparison highlights that phase separation of such compositions, commonly reported in the literature, does not occur for these mechanosynthesised materials of high homogeneity. Furthermore, high electrical performances can be obtained by this technique that can compete with some of the best reported in the literature. Electrical conductivity as a function of both oxygen and water partial pressure, in the temperature range of 550 °C − 850 °C, are measured for both compositions and the partial conductivities of protons, oxygen vacancies and electron holes are determined from the defect model. The electron-hole conductivity of BZY20 is observed to be higher than that of BZY15 under all conditions, while proton and oxide-ion conductivities are shown to be higher for the composition BZY15.

The mechanosynthesis process of composite powders for the preparation of a TiB2-20 wt pct MoSi2 composite material from reaction mixtures Ti + B + Mo + Si and Ti + B + MoSi2 in an argon atmosphere has been investigated. Synthesis proceeds according to mechanically stimulated reactions, and, in both cases, ultradisperse composite powders, along with the main phases, contain traces of lower silicides. The mathematical modeling of the distribution of interparticle contacts in the mixtures during solid-phase interaction has revealed a good agreement between the calculated and experimental data of mechanosynthesis. Spark plasma sintering in nonlinear regimes with a sequential increase in the sintering pressure from 6 MPa up to 50 MPa, accompanied by a decrease in the heating rate from 150 °C/min down to 50 °C/min, enables us to reduce the sintering temperature down to 1550 °C and obtain a dense composite with a mean size of TiB2 grains of about 200 nm. The TiB2-20 wt pct MoSi2 composite sintered at 1550 °C surpasses the composite sintered at 1750 °C in Vickers hardness (27.5 ± 3.2 GPa and 24.6 ± 2.2 GPa, respectively) but ranks below it in bending strength (480 ± 32 MPa and 571 ± 24 MPa, respectively).

Ti-based composite materials with remarkable mechanical properties and good thermal stability were obtained and studied with the purpose of employment for producing resistant and versatile components in the automotive industry. The raw materials having the overall Ti80Mn8Al6Sn3Zr2C1 composition were prepared by mechanosynthesis from powders of comprising elements; after thermal processing and by following four different sintering pathways, both in the argon flow, the four samples (S1–S4) reached a specific composition of metallic and ceramic phases. Thermal analysis and calorimetry showed that the composite materials adsorb considerable amounts of argon, these being related to the obtained composition and microstructure. The results of the thermal study were used when choosing the thermal treatment conditions for sintering; in order to select the optimal processing conditions within the four different regimes of sintering for the raw materials and the final sample with the best functional properties, a comprehensive study for determining the composition, structure and morphological features was carried out by means of X-ray diffraction, energy-dispersive X-ray spectroscopy and scanning electron microscopy. Two samples (S1 & S4) of the obtained composite materials have increased porosity due to the presence of titanium aluminium carbides (Ti3AlC & Ti3AlC2) that are known as highly porous ceramics, therefore absorbing more argon during the preparation process. The roughness and wear tests showed that the best results (smallest roughness: Ra = 1.11 μm and smallest wear: w = 2.472·10−4 mm3 N−1 m−1) belong to the S2 sample sintered in argon for 15 min at 1100 °C and further calcinated at 1050 °C for 75 min.

Pb0.67Cd0.33F2 solid solution with a fluorite-type structure has been synthesized for the first time using high-energy grinding of the initial components, PbF2 and CdF2, taken in a ratio of 2 : 1, in an inert Ar atmosphere. The dynamics of this process is investigated by X-ray diffraction analysis. The lattice parameter of the mechanosynthesis product is а = 5.768(7) A, and the average particle size is ∼50 nm.

International audience; The mechanically assisted synthesis of organic compounds has recently focused considerable attention as it may be unique in features to selectively direct the reaction pathway. In the continuation of our work on the synthesis of modified cyclodextrins (CDs) via mechanochemical activation, we sought to discriminate the contribution of supramolecular effects and grinding during the course of a reaction in the solid state. As such, we recently investigated the influence of the particle size of β-CD in the synthesis of β-CD mesitylene sulfonate (β-CDMts) in the solid state using a vibrating ball-mill. We were particularly interested in the role of the particle size on the kinetics of the reaction. In this study, we show that grinding β-CD reduces the particles size over time down to a limit of 167 nm. The granulometric composition remains rather invariant for grinding times over 1 h. Each type of β-CD particles reacted with mesitylenesulfonyl chloride (MtsCl) to produce β-CDMts. Contrary to what could be intuitively anticipated, smaller particles did not lead to the highest conversions. The impact of grinding on the conversion was limited. Interestingly, the proportion of β-CDMts mono-substituted on the primary face significantly increased over time when the reaction was carried out in the presence of KOH as a base. The data series were confronted with kinetics models to get insight in the way the reactions proceeded. The diversity of possible models suggests that multiple mechanochemical processes can account for the formation of β-CDMts in the solid state. Throughout the study, we found that the reactivity depended more upon diffusion phenomena in the crystalline parts of the material than on the increase in the surface area of the CD particles resulting from grinding.

The formation of the cubic δ-Ta1−xN phase by high-energy ball-milling from tantalum and boron nitride (h-BN) is explored. Two different molar ratios Ta:BN, 1:1 and 2:1, were used. X-ray diffraction, scanning electron microscopy, surface area analysis by the Brunauer-Emmett-Teller method, and thermogravimetric analysis were used to characterize the products obtained. In both molar ratios and after a few minutes of milling, the mechanosynthesis of δ-Ta1−xN was observed. Increasing the entropy of the system by introducing vacancies and point defects by the high-energy ball-milling process seems to stabilize the cubic δ-Ta1−xN phase, as previous theoretical studies had reported. The phase obtained depends on the molar ratio used: in the molar ratio 1:1 a non-stoichiometric δ-Ta1−xN phase is obtained, while in the molar ratio 2:1 a stoichiometric δ-TaN phase and secondary phases are obtained. The amorphous boron remains dispersed in the material until the mechanical energy is high enough to trigger the formation of tantalum borides.

Mechanochemical synthesis of CsPbI3 , as a model system for ABX3 halides, was studied. Water was shown to strongly promote the kinetics of formation of CsPbI3 from the CsI+PbI2 mixture through increased mobility of the constituting ionic species. Since many binary and ternary halides are hygroscopic, it was concluded that the presence of small, uncontrollable and unintentional additions of water should often occur in both precursor mixtures and synthesized complex halides boosting the kinetics of formation of many, if not all, ternary organic-inorganic hybrid halides such as, for example, MAPbX3 (X=Cl, Br, I). In addition, trace amounts of water should influence the transport characteristics of complex halides. Thus, the presence of water explains, at least partially, the huge scatter in both the reported mechanochemical reaction times necessary for obtaining single-phase APbX3 perovskite halides and the activation energies of ionic diffusion in APbX3 .

The six possible equiatomic five-transition metal High Entropy Carbides (HECs) of the IVB (Ti, Zr, Hf) and VB (V, Nb, Ta) groups of the periodic table, i.e., TiZrHfVNbC5, TiZrHfVTaC5, TiZrHfNbTaC5, TiZrVNbTaC5, TiHfVNbTaC5 and ZrHfVNbTaC5, were successfully obtained via a powder metallurgy route at room temperature, specifically, by one-step diffusion mechanosynthesis starting from the elemental constituents (using graphite as the carbon source). Three of those HECs, TiZrHfVTaC5, TiZrVNbTaC5 and ZrHfVNbTaC5, were developed for the first time. Their development was possible without any subsequent thermal treatment, in contrast to the usual way (reactive sintering at 1800–2200 °C), and in a powder form, make them potential advanced raw ceramics for hard, refractory and oxidation resistance coatings or matrix phase composites.

Inspired by mechanic force induced S–S bridge activation in a protein context, we have developed the first mechanochemical electrophilic C–H sulfenylation of indoles in combination with iodine cata...

Designable porous materials have potential in a plethora of applications, but synthesis costs and strict reaction conditions limit their true commercialization. Herein, we show that hypercrosslinke...

A novel highly efficient photocatalyst composite BiFeO3/Fe3O4 has been synthesized by mechanosynthesis and applied to the degradation of Methylene Blue under visible light. Structural, optical and photocatalytic properties of the proposed photocatalyst composites are carefully investigated. The nanointerfaces, associated to ferrous Fe2+ ions of the Fe3O4 nanoparticles, improve the photocatalytic efficiency when compared with pure BiFeO3 or Fe3O4. The time required to the complete degradation of Methylene Blue solution is 40 min for the sample with 20% of Fe3O4 which is more than 7 times faster than the time required using BiFeO3 alone. Moreover, with the addition of H2O2 a complete degradation is achieved just after 10 min, which is faster than any other photocatalytic reaction reported for BiFeO3-based materials. This enhancement is assumed to be related to an electron drain process due to the difference between energy levels of the conduction bands of BiFeO3 and Fe3O4 combined with the direct Fenton-like process associated with the Fe2+ ions of the composites.

This review is a compilation of the green synthetic methods used in the synthesis of coumarin derivatives. Coumarins are a class of compounds with a pronounced wide range of biological activities, which have found their application in medicine, pharmacology, cosmetics and food industry. Their biological activity and potential application are highly dependent on their structure. Therefore, many researchers have been performing the synthesis of coumarin derivatives on a daily basis. High demands for their synthesis often result in an increased generation of different waste chemicals. In order to minimize the utilization and generation of toxic organic substances, green synthetic methods are applied in this manner. These methods are getting more attention in the last few decades. Green chemistry methods cover a wide range of methods, including the application of ultrasound and microwaves, ionic liquids and deep eutectic solvents, solvent-free synthesis, mechanosynthesis and multicomponent reactions. All typical condensation reactions for coumarin synthesis like Knoevenagel, Perkin, Kostanecki-Robinson, Pechmann and Reformansky reactions, have been successfully performed using these green synthetic methods. According to the authors mentioned in this review, not only these methods reduce the utilization and generation of toxic chemicals, but they can also enhance the reaction performance in terms of product yields, purity, energy consumption and post-synthetic procedures when compared to the conventional methods. Due to the significance of coumarins as biologically active systems and the recent demands of reducing toxic solvents, catalysts and energy consumption, this review provides a first full literature overview on the application of green synthetic methods in the coumarin synthesis. It covers a literature search over the period from 1995-2019. The importance of this work is its comprehensive literature survey on a specific class of heterocyclic compounds, and those researchers working on the coumarin synthesis can find very useful information on the green synthetic approaches to their synthesis. There are some reviews on the coumarin synthesis, but most of them cover only specific reactions on coumarin synthesis and none of them the whole range of green chemistry methods.

Chemical science 11(9), 2350 - 2355 (2020). doi:10.1039/C9SC06224F, Using the mechanosynthesis of the calcium urea phosphate fertilizer cocrystal as a model, we provide a quantitative investigation of chemical autocatalysis in a mechanochemical reaction. The application of in situ Raman spectroscopy and synchrotron X-ray powder diffraction to monitor the reaction of urea phosphate and either calcium hydroxide or carbonate enabled the first quantitative and in situ study of a mechanochemical system in which one of the products of a chemical reaction (water) mediates the rate of transformation and underpins positive feedback kinetics. The herein observed autocatalysis by water generated in the reaction enables reaction acceleration at amounts that are up to 3 orders of magnitude smaller than in a typical liquid-assisted mechanochemical reaction., Published by RSC, Cambridge

Control over the bottom up synthesis of metal nanoparticles (NP) depends on many experimental factors, including the choice of stabilising and reducing agents. By selectively manipulating these species, it is possible to control NP characteristics through solution-phase synthesis strategies. It is not known, however, whether NPs produced from mechanochemical syntheses are governed by the same rules. Using the Au NPs mechanosynthesis as a model system, we investigate how a series of common reducing agents affect both the reduction kinetics and size of Au NPs. It is shown that the relative effects of reducing agents on mechanochemical NP synthesis differ significantly from their role in analogous solution-phase reactions. Hence, strategies developed for control over NP growth in solution are not directly transferrable to environmentally benign mechanochemical approaches. This work demonstrates a clear need for dedicated, systematic studies on NP mechanosynthesis.

Current time-resolvedin situapproaches limit the scope of mechanochemical investigations possible. Here we develop a new, general approach to simultaneously follow the evolution of bulk atomic and electronic structure during a mechanochemical synthesis. This is achieved by coupling two complementary synchrotron-based X-ray methods: X-ray absorption spectroscopy (XAS) and X-ray diffraction. We apply this method to investigate the bottom-up mechanosynthesis of technologically important Au micro and nanoparticles in the presence of three different reducing agents, hydroquinone, sodium citrate, and NaBH4. Moreover, we show how XAS offers new insight into the early stage generation of growth species (e.g.monomers and clusters), which lead to the subsequent formation of nanoparticles. These processes are beyond the detection capabilities of diffraction methods. This combined X-ray approach paves the way to new directions in mechanochemical research of advanced electronic materials.

Green mechanosynthesis, free solvent, has been used for preparing a series of supramolecular complexes. Through directional hydrogen bonds and π-cation interaction can be prepared complexes with different states of aggregation of matter, where stoichiometry plays an essential role. When the stoichiometric ratio between the two compounds was 1:1, a solid product is obtained. But, when the ratio is higher, products are obtained as gel or paste to reach low viscosity liquids. Also, the structure of such complexes that form three-dimensional aggregates between C12TAC and phenol derivatives can explain the different aggregation states for final products and this may be the key to understand the viscosity reduction mechanism. Keywords: Supramolecular complex, Mechanosynthesis, Hydrogen bond, Π-cation interactions, Change of physical state

—X-ray diffraction, Mossbauer and Raman spectroscopy have been used to study structural phase transformations during mechanosynthesis of Fe–С60/70 in toluene with 20 and 25 at % С60/70 fullerite. The quantitative carbon content determines the phase composition of mechanocomposites. (Fe3C)D forms at 20 at % С60/70, whereas Fe7C3 and a paramagnetic phase form at 25 at % С60/70 at the initial stage of mechanical alloying. Free carbon is in an amorphous state in the sample. The formation mechanism of carbides and a paramagnetic component is discussed.

The CsCl/LiCl system has been studied for over a century now. Numerous phases have been predicted - only three have hitherto been found. We present the synthesis and single-crystal structure of the cesium lithium pentachloride Cs3Li2Cl5, predicted earlier but with a different structure. The anhydrous new phase readily reacts to Cs3LiCl4 · 4H2O in air. The tetrahydrate can also be obtained through the simplest, most inexpensive and green synthesis possible: an immediate, room-temperature mechanosynthesis from only CsCl and LiCl (3 : 1) in air. Differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA), as well as in situ temperature-dependent powder X-ray diffraction studies on this second ever reported ternary alkali chloride hydrate allowed for a revision of the CsCl/LiCl phase diagram. Density of states and total energy calculations further elucidate the new alkali chlorides and update the relative stability of previous structure predictions.

The structural changes of fullerite C60/70 during mechanosynthesis of composites Me-25 at%C60/70 (Me = Cu, Fe) have been studied by X-ray diffraction analysis and Raman spectroscopy. It is found that depending on the milling time and carbon affinity for metal, partial or complete disordering of the fullerite C60/70 crystalline structure and destruction of fullerene molecules take place. Their deformation stability determines the sequence of solid-phase reactions in the investigated systems. The local atomic environment in the Fe-C60/70 has been studied by Moessbauer spectroscopy. It is shown that the mechanism of the phase formation in the Fe-C60/70 is as follows: the Fe3C carbide is crystallized from an amorphous phase Am(Fe-C).

In the present study, a new low-viscous sulfonic acid-functionalized ionic liquid (SAIL) viz. 4,4′-trimethylene-N,N′-sulfonic acid-dipiperidinium chloride was synthesized and characterized by FTIR, 1D and 2D NMR, and Mass spectra. Then, some properties of new SAIL were determined including pH, viscosity, density, and solubility in some common solvents. The catalytic activity of new SAIL was demonstrated for the one-pot mechanosynthesis of pyrano[4,3-b]pyrans, dihydropyrano[3,2-c]chromene and tetrahydrobenzo[b]pyrans using planetary ball mill under solvent-free conditions. This current mechanosynthesis methodology for the synthesis of 4H-pyran-annulated heterocyclic scaffolds displays a combination of the synthetic virtues of conventional multi-component reaction with ecological benefits and convenience of a simple mechanocatalytic procedure. New SAIL was easily recycled and reused several times with no significant loss of activity.

In the present study, the catalytic efficiency of 1,1′-butylenebis(3-sulfo-3H-imidazol-1-ium) hydrogensulfate (BBSI-HSO4) as a versatile sulfonic acid-functionalized ionic liquid was demonstrated for the one-pot mechanosynthesis of pyrano[4,3-b]-pyrans using planetary ball mill at room temperature under solvent-free conditions. This efficient mechanosynthesis approach to the 4H-pyran scaffolds displays a combination of the structure–activity relationship of ionic liquids with ecological benefits of a mechanocatalytic procedure. The ionic liquid was easily recycled and reused several times with no significant loss of its catalytic activity.

The single phase lanthanum orthoniobate with tetragonal structure has been synthesized by the means of mechanosynthesis method. The studies have shown the crystal structure of La0.98Ca0.02NbO4 depends on the synthesis stage. The samples were predominantly in the tetragonal phase with a trace amount of the monoclinic phase. The SEM studies of morphology and microstructure have shown nanocrystallinity of the materials. The Raman studies showed the significant difference between the Raman spectra of nano- and microcrystalline La0.98Ca0.02NbO4. A decrease of Debye temperature, shown a change of thermal properties due to the presence of nano-sized particles in La0.98Ca0.02NbO4. Electrical characterization results suggest the protons are predominant charge carries in the material for the whole measured range of temperature and shows the total conductivity value of 4.0 × 10−5 S cm−1 at 600 °C in wet air. The calculated activation energies were equal to (0.81 ± 0.04) eV under dry and (0.73 ± 0.06) eV under humidified conditions. That indicates that nanostructuring was successfully stabilized the high-temperature tetragonal phase.

Piperlotines are natural products characterized by an α,β-unsaturated amide moiety. These compounds found wide applications in Medicinal Chemistry like antibacterials, cytotoxic agents, anticoagulants, among others. To date, diverse methods of synthesis have been reported for piperlotines, but involving the use of catalysts, hazard reagents, anhydrous media or coupling reagents. Thus, in this work, we developed a greener method of synthesis of piperlotines A, C, and derivatives, through mechanochemical activation under solvent-free conditions. The reaction of a β-amidophosphonate, K2CO3, and an aromatic aldehyde afforded target compounds in moderate to good yields (46-77%), in an open atmosphere by grinding. It is worth to mention that this mechanochemical process was under thermodynamic control because just E isomer was isolated for every reaction. Moreover, synthesized piperlotines have been predicted by means of chemoinformatic analysis as potential therapeutic agents for the treatment of arthritis or cancer.

The high-energy ball milling of Ti, Nb and Cu powders in liquid hydrocarbon and magnetic pulse compaction have been successfully used to produce Ti2CH0.6–(CuTi2, CuTi) and NbC–Cu composites with a density of 94–97% of the theoretical value, a microhardness of 4–5 GPa and high abrasive wear resistance

This work reports the preparation of HZSM-5/SBA-15 micro-mesoporous materials with composite structure by mechanosynthesis and their use as templates to micro-mesoporous carbons, with palm oil cooking waste as carbon source. HZSM-5/SBA-15 composites were prepared in different mass proportions (25:75, 50:50 and 75:25) by a mechanosynthetic strategy. The palm oil waste was infiltrated into the template pores by a two-step procedure involving grinding followed by stirring the suspension in an oil solution and carbonization under inert atmosphere. SEM images showed the efficiency of mechanosynthesis for all mass proportions, while textural properties were strongly influenced by the presence of SBA-15. A comparison of 50% HZSM-5/SBA-15 mixture with pristine SBA-15 and uncalcined SBA-15 as carbon templates evidenced that the 50% HZSM-5/SBA-15 mixture lead to the carbon with the highest surface area and pore volume. The resulting carbon material was studied as adsorbent to different dye molecules, including molecules with different charges and sizes. Results revealed that the carbon has a significantly higher affinity for cationic dyes, that the mesopore structure favors high diffusion rates and that the surface groups have a very high affinity for cationic dye molecules.

An efficient and simple methodology was proposed to synthesize bimetallic Co–Zn based zeolitic imidazolate frameworks (CoZn-ZIFs; CoxZn(1−x)(2-methylimidazole)2) with sodalite topology. The synthesis strategy is based on a solventless mechanochemical reaction using only powder raw material, zinc oxide, cobalt acetate, and 2-methylimidazole, for ease of handling and large-scale production. The solventless conversion of ZnO into CoZn-ZIF could be promoted by adding cobalt acetate as both Co source and catalyst. A feature of the acetate-assisted mechanosynthesis is that CoZn-ZIF particles are tens of micrometers in size and hierarchically structured. Co and Zn elements are homogeneously dispersed in the framework. Tuning the additive amount of cobalt acetate could vary the Co/Zn ratio of CoZn-ZIF particles. Compared with Zn-ZIF prepared by adding zinc acetate, CoZn-ZIFs exhibited enhanced CO2 uptake. The enhancement of 35% for CO2 uptake capacity at 298 K and 100 kPa was displayed by Co0.9Zn0.1-ZIF as compared to Zn-ZIF.

Water pollution by various toxic heavy-metal ions, particularly mercury and lead, has been considered as a global problem with serious threat to public health. Nowadays, a variety of adsorbents have been used extensively for the removal of heavy-metal ions from water. In this work, two Zn-based metal–organic frameworks (MOFs), named TMU-31 and TMU-32, were successfully synthesized by a solid-state method named mechanosynthesis, which can be considered as a rapid, green, convenient, solventless, and low-cost process. These two MOFs are densely decorated with urea functional groups, which results in rapid, efficient, and selective removal of diverse heavy-metal ions, such as Hg2+ and Pb2+ ions, from wastewater. The sorption capacities of 476.19 mg g–1 in less than 15 min for Hg(II) ions and 909 mg g–1 for Pb(II) metal ions in less than 5 min were obtained effectively by these two structures. In addition, adsorption isotherms of Hg2+ and Pb2+ metal ions are in good agreement with Langmuir model, and also, th...

The products of mechanosynthesis in the systems “superstoichiometric fluorocarbon nanomaterial CF1.2–thermally expanded graphite” are studied using X-ray photoelectron spectroscopy and low-temperature nitrogen adsorption to identify texture characteristics. A correlation is revealed between the conductivity of the composites and functional composition of their surface layers. The obtained results are explained by the fact that mechanosynthesis products contain mesoporous carbon-fluorocarbon nanocomposites consisting of micro- and nanoparticles CF1+x coated by an outer nanolayer sp2-C–sp3-C–F.

1,1′-(1,4-Butanediyl)bis(imidazole) was prepared by a modified method and its application as an efficient promoter was demonstrated for the mechanosynthesis of N-methyl imines using ball milling as a non-conventional process under solvent-free conditions. In this new protocol design, the bis-imidazole acted as a recyclable acid-scavenging agent. This efficient approach to the N-methyl imines displays a combination of the synthetic virtues of a non-conventional condensation reaction with ecological benefits and convenience of a facile mechanosynthetic process. The current method has advantages such as reduced waste by avoiding solvent, exclusion of hazardous materials during the reaction, elimination of handling an anhydrous gas in an evacuated container or a solution of methylamine in ethanol, good yields for relatively unreactive benzaldehydes containing electron-donating substituents, short reaction times, and metal- and acid-free conditions. Furthermore, the promoter was easily regenerated and reused several times with no significant loss of activity.

Niobium carbonitride [Nb(C,N)] nanoparticles were synthesized by a combustive mechanochemical reaction in the Mg/Nb2O5/C3H6N6 system. High-energy ball milling was used to promote a mechanically induced self-sustaining reaction (MSR). Combustion occurred after a very short milling period of 5 min. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS) analyses revealed that the nature of the product is an intermixed carbonitride material. The formation mechanism of Nb(C,N) resulted from the magnesiothermic reduction of niobium oxide to generate elemental Nb, which then reacted with the species generated from the melamine decomposition., This work was supported by both the Iran University of Science and Technology (IUST) and the Spanish government with a grant No. MAT2014-52407-R.

La2/3Cu3Ti4O12 (LCTO) powder has been synthesized by the mechanochemical milling technique. The pelletized powder was conventionally sintered for 10 h at a temperature range of 975–1025 °C, which is a lower temperature process compared to the standard solid-state reaction. X-ray diffraction analysis revealed a cubic phase for the current LCTO ceramics. The grain size of the sintered ceramics was found to increase from 1.5 ± 0.5 to 2.3 ± 0.5 μm with an increase in sintering temperature from 975 to 1025 °C. The impedance results show that the grain conductivity is more than three orders of magnitude larger than the grain boundary conductivity for LCTO ceramics. All the samples showed a giant dielectric constant (1.7 × 103–3.4 × 103) and dielectric loss (0.09–0.17) at 300 K and 10 kHz. The giant dielectric constant of the current samples was attributed to the effect of internal barrier layer capacitances due to their electrically inhomogeneous structure.

Oxides with perovskite structure are the target of important studies, as they are versatile materials that have shown magnetic, electrical, optical, catalytic, adsorptive applications, among others, and are also easily synthesized. These applications are potentially influenced by the synthesis method, and in this sense, several methods have been used to prepare these materials, in order to optimize their characteristics and properties. The methods: modified protein using gelatin as a complexing agent, mechanosynthesis and combustion method in the heating plate and microwave were used to prepare LaNiO3 type materials with perovskite structure used in the present work. The materials obtained were characterized by physical-chemical techniques (X-ray diffraction, nitrogen adsorption at 77 K and determination of the point of zero charge) and evaluated as an adsorbent for the removal of methylene blue dye in aqueous medium. All materials showed potential for removing the dye from the medium, with emphasis on the material obtained by mechanosynthesis, which presented higher methylene blue dye discoloration efficiency, due its smaller crystallite size and larger surface area. After the dye removal tests, the perovskite structure was preserved and the adsorbent was reused after being subjected to calcination at 900 °C for 2 hours when simultaneous degradation of the previously adsorbed dye occurred. The reused materials still had a high potential for dye removal.

International audience; (R)-1,2-Diaminobicyclo[2.2.2]octane was used as a starting material for the preparation, in solution or in a ball mill, of a salen ligand. Five metal salen complexes were prepared in high yield and their cytotoxic activities were evaluated against the Human Colon cancer HCT116 cell lines. The original manganese salen complex displayed the highest activity with a potency 16 fold higher than that of cisplatin, demonstrating the benefit of the bridging backbone compared to other salen systems. An alternative preparation route for this complex by mechanochemistry was also performed.

Mechanosynthesis is a powerful alternative to traditional solvent-based synthesis as it allows for higher yields in shorter reaction times, while minimizing the use of solvents. Although mechanochemical routes are becoming increasingly mainstream in synthetic laboratories, up-scaled examples for main group complexes are still rare. Here, motivated by the practical implementation of mechanosynthesis, we demonstrated the synthesis of salen and salophen complexes. The herein reported synthesis displays low E-factor and process mass intensity compared to conventional solution methods. In addition, analyses evaluating environmental parameters, energy consumption, and production cost have been performed, showing the multiple advantages mechanochemistry has over conventional solution-based synthesis. Agency for Science, Technology and Research (A*STAR) Ministry of Education (MOE) Nanyang Technological University F.G. would like to acknowledge A*STAR AME IRG (A1783c0003 and A2083c0050), MOE AcRF Tier 1 (M4011709), and NTU start-up grant (M4080552) for financial support. F.L and V.S. would like to thank A*STAR for fellowship. O.H.C would like to thanks NTU for NPGS scholarship.

The Y-halides Li3YBr6 and Li3YCl6 have recently gained considerable attention as they might be used as ceramic electrolytes in all-solid-state batteries. Such materials need to show sufficiently hi...

International audience; Fourteen dyes based on 2,4,5,7-tetranitrofluorene (TNF) as the electron acceptor have been designed and prepared in a one-step synthesis. By modifying the electron donor, optical properties of the dyes could be efficiently tuned and an absorption ranging between 450 nm and 700 nm could be determined by UV-visible absorption spectroscopy. To get a deeper insight into the optical properties, solvatochromism of the fourteen dyes has also been examined. For all dyes, a positive solvatochromism was determined using different solvent polarity scales such as the Kamlet-Taft and the Catalan empirical scales. Finally, electrochemical properties were also examined, and a comparison of the electrochemical and optical bandgaps could be established. Theoretical calculations were also performed to characterize the different dyes.

International audience; Crystalline gallium (III) sulfide Ga2S3 samples have been prepared by mechanical-alloying instead of usual heating process. A safe, energy-efficient, and fast process of only 4 h of mechanosynthesis led to the formation of polycrystalline Ga2S3 from pure Ga and S as raw materials. X-ray diffraction measurements and Rietveld refinements show that the as-prepared material is a mixture of mainly hexagonal wurtzite-type β-phase (68 ± 5 wt%; space group P63mc (No. 186)) along with some cubic sphalerite-type γ-phase (32 ± 5 wt%; space group F-43m (No. 216)). In situ high-temperature X-ray diffraction measurements show that the monoclinic phase (space group Cc (No. 9)) appears at 450 °C. Scanning electron microscopy analyses reveal that the morphology of the powder is characterized by aggregates of nanometric particles. Their sizes measured by laser diffraction show a median size around 170 nm after 4 h of ball-milling.

Mechanochemistry is becoming an established method for the sustainable, solid-phase synthesis of scores of nano-materials and molecules, ranging from active pharmaceutical ingredients to materials for cleantech. Yet we are still lacking a good model to rationalize experimental observations and develop a mechanistic understanding of the factors at play during mechanically assisted, solid-phase nanoparticle synthesis. We propose herein a structural-phase-field-crystal (XPFC) model with a ballistic driving force to describe such a process, with the specific example of the growth of gold nanoparticles in a two component mixture. The reaction path is described in the context of free energy landscape of the model, and dynamical simulations are performed based on phenomenological model parameters closely corresponding to the experimental conditions, so as to draw conclusions on nanoparticle growth dynamics. It is shown that the ballistic term lowers the activation energy barrier of reaction, enabling the reaction in a temperature regime compatible with experimental observations. The model also explains the mechanism of precipitated grain size reduction that is consistent with experimental observations. Our simulation results afford novel mechanistic insights into mechanosynthesis with implications for nanaparticle production and beyond., 47 pages, 11 figures

A series of salts and binary and ternary cocrystals of the antimalaria drug pyrimethamine (PYR) are reported. PYR has a donor–acceptor–donor (DAD) and a donor–acceptor (DA) binding site, and cocrystallization experiments were performed with coformers with complementary acceptor-donor-acceptor (ADA) and acceptor-donor (AD) H-bonding functionalities. Three different preparation techniques were compared, namely, solution crystallization, crystallization from the gas phase, and liquid-assisted grinding. In several cases different solid-state forms were obtained depending on the crystallization method. The molecular ionic cocrystals PYRH+BAR–·PYR (BAR = barbituric acid) and (PYRH+SAC–)2·GLU (GLU = glutarimide, SAC = saccharin), the binary cocrystal PYR·GLU, the salt PYRH+NIC– (NIC = nicotinic acid), and two polymorphs of PYRH+SAC– could be crystallized by sublimation. Two other ternary molecular ionic cocrystals, (PYRH+BEN–)·PYR·SUC and (PYRH+SAC–)2·SOR (SUC = succinimide, BEN = benzoic acid, SOR = sorbic acid), were obtained by solution crystallization. Attempts to crystallize ternary cocrystals from solution also yielded a number of new two-component cocrystals including four new solvates of PYRH+SAC–, thus extending the structural landscape of the PYR/SAC system. Liquid-assisted milling was performed as a one-pot reaction and with the stepwise addition of the coformers. The (PYRH+SAC–)2·GLU cocrystal formed when the coformers were milled in one step and when they were added to the mill stepwise. For other systems the outcome of the two-step milling experiment depended on the order in which the coformers were added. The PYR-coformer interactions were analyzed using the PIXEL program. This publication has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) and is co-funded under the European Regional Development Fund under Grant Number 12/RC/2275. peer-reviewed 2021-11-24

We report a simple, efficient, and scalable mechanochemical method of preparation of new creatine fitness supplement with increased solubility (compared to the creatine monohydrate) and decreased acidity (compared to creatine hydrochloride).

International audience; Mechanosynthesis was used to obtain pure crystalline powders of a 2D Ruddlesden-Popper type Cs2(Pb1.xBix) Cbl2 phase, with O ???? x :$ 0.15. These newly discovered compounds present interesting physical properties that may make them suitable for electronic devices, including LEDs and photovoltaics. Detailed structural analysis based on X-ray diffraction (XRD) data shows that lead substitution by bismuth reduces the unit cell parameters. A significant color change of the material has been observed with a clear red-shift related to the Bi doping content. The introduction of bismuth into the structure also induces strains as evidenced by XRD peak enlargemen'Πbut the material can be pure up to x = 15 mol.%. A first ageing study shows that these strains seem to be released with time and that Cs2PbClilz and 5 mol.% Bi-doped Cs2PbClilz materials remain pure after a month in air.

The Miedema model is used to estimate the enthalpy of intermetallic compounds and the solid solution of ternary systems. The results showed that the chemical enthalpy values of the binary systems (Fe-Al, Fe-B, Fe-V, Fe-Ga, Al-V, and Al-Mn) are negative. Whereas, the chemical enthalpy values of the binary systems (Fe-Mn and Al-Ga) are positive. The most negative enthalpy is observed for Fe-Al-Ga, Fe-Al-B, and Fe-Al-Sn systems with a mole fraction of 50% of Fe. For ternary systems, the enthalpy varies with the mole fractions of the components. Studies of the products of mechanosynthesis - binary alloy and Fe-Al-based ternary systems: Fe65Al35, Fe65Al35-xMx (Mx = Ga, B, Sn; 5 and 10 at. %) and Fe65-yAl35My (My = Mn, V; 3, 5 and 10 at. %) were confirmed. It concluded that the applicability of the Miedema model for prognostic purposes for estimating the enthalpies and the possibility of obtaining multicomponent systems.

We present a rapid and readily scalable methodology for the mechanosynthesis of diverse metal–organic frameworks (MOFs) in the absence of milling media typically required for other types of mechanochemical syntheses. We demonstrate the use of liquid-assisted resonant acoustic mixing (LA-RAM) methodology for the synthesis of three- and two-dimensional MOFs based on Zn(ii), Co(ii) and Cu(ii), including a mixed ligand system. Importantly, the LA-RAM approach also allowed the synthesis of the ZIF-L framework that has never been previously obtained in a mechanochemical environment, as well as its Co(ii) analogue. Straightforward scale-up from milligrams to at least 25 grams is demonstrated using the metastable framework ZIF-L as the model., We present a rapid and readily scalable methodology for the mechanosynthesis of diverse metal–organic frameworks (MOFs) in the absence of milling media typically required for other types of mechanochemical syntheses.

This paper presents a green protocol for the synthesis of pyrano[4,3-b]pyrans using a catalytic amount of 4,4′-trimethylenedipiperidine (TMDP) as a novel, efficient and recyclable organocatalyst through ball milling process at room temperature. The essential part of this protocol is a Knoevenagel condensation and to the best of our knowledge, this is the first report that exhibits the catalytic efficiency 4,4′-TMDP for the one-pot multicomponent reaction under melt-state conditions. The scope of the present protocol was explored and demonstrated for the synthesis of pyrano[4,3-b]pyrans in an environment-friendly protocol. The several interesting features of the present methodology are including a cost-effectiveness procedure, good to excellent yield of the desired products, high reaction rate, a broad substrate-scope, and recyclability of organocatalyst; as well as the 4,4′-TMDP is a nontoxic, inexpensive, and commercially available catalyst. Furthermore, this efficient methodology displays a combination of the synthetic virtues of conventional multicomponent reaction with ecological benefits and convenience of a facile mechanochemical process.

International audience; The use of ball mills enabled the efficient mechanosynthesis of a variety of N-aryl,N-alkyl imidazolium salts and of corresponding NHC silver(I) complexes. Transmetalation with ruthenium via mechanochemistry allowed the rapid access (from 1.5 min to 1 h) to complexes having a similar structure to Noels-type precatalysts. Evaluation of the complexes in the ring-opening metathesis polymerization of norbornene in different solvent, including nontoxic ones, showed a high catalytic activity for one of them, comparable to that of the Noels catalyst.

Chalcopyrite CuFeS2 was shown to be a promising thermoelectric material. Considering thermoelectric efficiency, its relatively high and temperature weakly dependent power factor, economic affordability and ecological benignity is counterbalanced by a high lattice thermal conductivity. Thus it is highly desirable to lower the thermal conductivity of chalcopyrite thermoelectric material without deterioration of other thermoelectric characteristics. In our study, we demonstrate that mechanosynthesis followed by appropriate sintering enables to prepare such nanostructured ceramics with a favourable thermoelectric response. Our study shows that mechanosynthesis is a low-cost technological route for the production of thermoelectric chalcopyrite ceramics. Chalkopyrit CuFeS2 se ukázal jako slibný termoelektrický materiál. Vzhledem k termoelektrické účinnosti je její relativně vysoký a teplotně slabě závislý účiník, ekonomická dostupnost a ekologická neškodnost vyvážena vysokou tepelnou vodivostí mřížky. Proto je velmi žádoucí snížit tepelnou vodivost termoelektrického materiálu chalkopyritu bez zhoršení dalších termoelektrických vlastností. V naší studii dokazujeme, že mechanosyntéza následovaná vhodným slinováním umožňuje připravit takovou nanostrukturovanou keramiku s příznivou termoelektrickou odezvou. Naše studie ukazuje, že mechanosyntéza je levnou technologickou cestou pro výrobu termoelektrické keramiky z chalkopyritu.

Synthesis of hydrazones (1a–4a and 1b–4b), quinazolines (3c*MeOH and 3d*MeOH), and hydrazone- Schiff bases (4c and 4d) is achieved by combining suitable aldehydes (2, 3- or 2, 4- ihydroxybenzaldehyde) with four hydrazides (isonicotinic, nicotinic, and 2- or 4-aminobenzoic acid hydrazide). A suite of approaches for their preparation is described: solution-based synthesis, mechanosynthesis, and solid-state melt reactions. The mechanochemical approach is generally a better choice for the quinazolines, while the solid-state melt reaction is more efficient for derivatives of (iso)nicotinic based hydrazones. Crystalline amine-functionalised hydrazones 4a and 4b undergo post-synthetic modifications in reactions with 3- or 4- pyridinecarbaldehyde vapours to form hydrazone- Schiff bases 4a-3py, 4b-3py, 4a-4py, and 4b4py. Mechanochemical and vapour-mediated reactions are followed by ex situ powder X-ray diffraction and IR-ATR methods, respectively. The chemometric analysis of these data using principal component analysis provided an insight into the reaction profiles and reaction times. Azines (5a and 5b), achieved from aldehydes and hydrazine, reversibly change colour in response to temperature changes. The structures of all products are ascertained by a combined use of spectroscopic and X-ray diffraction methods. The cytotoxic and antimicrobial activities of all compounds against selected human cancer cell lines and bacterial strains are evaluated.