Mechanochemical Synthesis of Fluorinated Imines

A number of imines, including 12 new compounds, previously not reported in the literature, derived from variously fluorinated benzaldehydes and different anilines or chiral benzylamines were synthesized by a solvent-free mechanochemical method, which was based on the manual grinding of equimolar amounts of the substrates at the room temperature. In a very short reaction time of only 15 min, the method produced the expected products with good-to-excellent yields. The yields were comparable or significantly higher than those reported in the literature for the imines synthesized by other methods. Importantly, the conditions used for the reactions with aniline derivatives also resulted in the high yields of imines obtained from chiral benzylamines, and can be extended to the synthesis with other similar amines. Structures of all imines were confirmed by NMR spectroscopy: ¹H, ¹³C and ¹⁹F. For four compounds, X-ray structures were also obtained. The synthetic approach presented in this paper contributes to the prevention of environmental pollution and can be easily extended for larger-scale syntheses. The mechanochemical solvent-free method provides a convenient strategy particularly useful for the preparation of fluorinated imines being versatile intermediates or starting material in the synthesis of drugs and other fine chemicals.     

Mechanochemical Synthesis of Catalytic Materials

The mechanochemical synthesis of nanomaterials for catalytic applications is a growing research field due to its simplicity, scalability, and eco-friendliness. Besides, it provides materials with distinct features, such as nanocrystallinity, high defect concentration, and close interaction of the components in a system, which are, in most cases, unattainable by conventional routes. Consequently, this research field has recently become highly popular, particularly for the preparation of catalytic materials for various applications, ranging from chemical production over energy conversion catalysis to environmental protection. In this Review, recent studies on mechanochemistry for the synthesis of catalytic materials are discussed. Emphasis is placed on the straightforwardness of the mechanochemical route—in contrast to more conventional synthesis—in fabricating the materials, which otherwise often require harsh conditions. Distinct material properties achieved by mechanochemistry are related to their improved catalytic performance.     

快离子导体的机械化学合成

快离子导体是二次高能电池及其他全固体电化学器件研制与开发的重要材料，常规方法由于存在原材料选择受限以及原料对容器侵蚀等技术问题，致使一些高性能快离子导体的制备受到很大限制。为此，人们将目标转移到不需加热、在室温条件下即可实现这一材料制备的机械化学合成法。本文总结了近年来利用这种方法在制备快离子导体方面取得的一些最新研究成果。     

铁酸锌纳米晶的机械化学合成

以αFe₂O₃和ZnO粉体为原料,在高能球磨的作用下,室温(约25℃)合成了铁酸锌(ZnFe₂O₄)纳米晶.用XRD、TEM、M?sbauer谱及IR光谱等方法对纳米晶进行了表征.结果表明:所得纳米晶具有非正型分布的尖晶石结构,为超顺磁性;纳米晶内存在着较多的缺陷.     

Mechanochemical Synthesis of Stimuli Responsive Microgels

Mechanochemical approaches are widely used for the efficient, solvent-free synthesis of organic molecules, however their applicability to the synthesis of functional polymers has remained underexplored. Herein, we demonstrate for the first time that mechanochemically triggered free-radical polymerization allows solvent- and initiator-free syntheses of structurally and morphologically well-defined complex functional macromolecular architectures, namely stimuliresponsive microgels. The developed mechanochemical polymerization approach is applicable to a variety of monomers and allows synthesizing microgels with tunable chemical structure, variable size, controlled number of crosslinks and reactive functional end-groups.     

Mechanochemical Synthesis of Short DNA Fragments

We demonstrate the first mechanochemical synthesis of DNA fragments by ball milling, enabling the synthesis of oligomers of controllable sequence and length using multi-step, one-pot reactions, without bulk solvent or the need to isolate intermediates. Mechanochemistry allowed for coupling of phosphoramidite monomers to the 5′-hydroxyl group of nucleosides, iodine/water oxidation of the resulting phosphite triester linkage, and removal of the 5′-dimethoxytrityl (DMTr) protecting group in situ in good yields (up to 60 % over three steps) to produce DNA dimers in a one-pot manner. H-Phosphonate chemistry under milling conditions enabled coupling and protection of the H-phosphonate linkage, as well as removal of the 5′-DMTr protecting group in situ, enabling a one-pot process with good yields (up to 65 % over three steps, or ca. 87 % per step). Sulfurization of the internucleotide linkage was possible using elemental sulfur (S8) or sulfur transfer reagents, yielding the target DNA phosphorothioate dimers in good yield (up to 80 % over two steps). This work opens the door to creation of solvent-free synthesis methodologies for DNA and RNA therapeutics.     

Mechanochemical Synthesis of Corannulene-Based Curved Nanographenes

It is shown that corannulene-based strained π-surfaces can be obtained through the use of mechanochemical Suzuki and Scholl reactions. Besides being solvent-free, the mechanochemical synthesis is high-yielding, fast, and scalable. Therefore, gram-scale preparation can be carried out in a facile and sustainable manner. The synthesized nanographene structure carries positive (bowl-like) and negative (saddle-like) Gaussian curvatures and adopts an overall quasi-monkey saddle-type of geometry. In terms of properties, the non-planar surface exhibits a high electron affinity that was measured by cyclic voltammetry, with electrolysis and in situ UV/vis spectroscopy experiments indicating that the one-electron reduced state displays a long lifetime in solution. Overall, these results indicate the future potential of mechanochemistry in accessing synthetically challenging and functional curved π-systems.     

Mechanochemical Synthesis of Nanosize Metastable Zirconium Oxide

The formation of oxide phases in the course of mechanical activation of amorphous zirconium hydroxide was studied.     

Synthesis of NaA Zeolite by Mechanochemical Methods

A method for obtaining NaA zeolite by mechanochemical activation of a raw material is proposed. The method produces no wastewater in the course of zeolite synthesis.     

Mechanochemical Synthesis and Reactivity of a Stable Nickel Borohydride

We report the solvent-assisted mechanochemically synthesised mononuclear Ni(II) borohydride complex supported by a macrocyclic tetradentate ligand. It was characterised as stable high-spin [(L^Me)Ni(η²-BH₄)]⁺ cation in solid-state and in solution by various physicochemical methods and capable of transferring hydride. The stoichiometric reactivity of [(L^Me)Ni(η²-BH₄)]⁺ cation was examined with trityl cation, alkyl halide, disulphide, thiol, carboxylic acid and enol at room temperature.     

Ambient Temperature Graphitization Based on Mechanochemical Synthesis

Graphite has become a critical material because of its high supply risk and essential applications in energy industries. Its present synthesis still relies on an energy-intensive thermal treatment pathway (Acheson process) at about 3000 °C. Herein, a mechanochemical approach is demonstrated to afford highly crystalline graphite nanosheets at ambient temperature. The key to the success of our methodology lies in the successive decomposition and rearrangement of a carbon nitride framework driven by a denitriding reaction in the presence of magnesium. The afforded graphite features high crystallinity, a high degree of graphitization, a thin nanosheet architecture, and a small flake size, which endow it with superior efficiency in lithium-ion batteries as an anode material in terms of rate capacity and cycle stability. The mild and cost-effective pathway used in this study could be a promising alternative for graphite production.     

Mechanochemical Synthesis of Nitrogen-containing Derivatives of Flax Boon

The influence exerted by the conditions of the mechanochemical synthesis [time (100–100 min), air pressure (1–9 atm), temperature (30–90°C), amount of ammonia (0.5–3.0 g g^?1 raw material)] on the content of nitrogen and functional groups in the products of oxidative ammonolysis of flax boon was studied. The resulting products were tested as nitrogen-containing ion exchangers in sorption of heavy metals.     

Mechanochemical Synthesis of Ternary Potassium Transition Metal Chlorides

Ternary halide systems KM^IICl₃ (M^II = Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn) have been prepared by mechanochemical synthesis. Furthermore, TiCl₂ was converted to Ti₇Cl₁₆ by mechanochemical treatment. For most samples, the X‐ray powder diffraction patterns could either be assigned to isotypic structures or were found in accordance with reference data. The monochloride systems of Ti, Co and Zn were extended to their double chloride stoichiometry K₂M^IICl₄.     

Effective Mechanochemical Synthesis of [60]Fullerols

Abstract

[60]Fullerols which show an average composition of C₆₀(OH)_27.2 were synthesized effectively in high yield under the high-speed vibration milling (HSVM) conditions in air at room temperature.     

Mechanochemical Synthesis of Poly(germanium and tin organosiloxanes)

The mechanochemical reaction of polyphenylsiloxane with tin and germanium oxides gives rise to soluble tin and germanium phenylsiloxanes. Effect of the nature of the oxide and of the starting reagent ratio on the yield and composition of metal phenylsiloxanes was studied. The reaction products were studied by IR spectroscopy and X-ray phase analysis.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 4, 2005, pp. 610–613.Original Russian Text Copyright © 2005 by Kapustina, Shapkin, Ivanova, Lyakhina.