Metal mechanochemical synthesis

In a variant of the second method described earlier the premixed metallic powders (or pulverized ingots) are milled under hydrogen atmosphere to directly form an intermetallic hydride. It can be also viewed as hydrogen alloying of metal powders and powder mixtures in hydrogen alloying mills. This method is called a reactive mechanical alloying (RMA) or mechanochemical synthesis (MCS). 

Mechanochemical synthesis (MCS) by reactive milling of metal powders or intermetaUics in hydrogen gas... 

Fig. 11 Crystal structure of a metal-organic framework material Zn2(fina)2(bipy) prepared by mechanochemical synthesis, with the structure determined directly from powder XRD data. The structure is viewed (a) along the c-axis and (b) along the b-axis. The two (identical) interpenetrated frameworks are indicated by yellow and purple shading. For comparison, (c) and (d) show the corresponding views of the stmcture of a DMF solvate material Zn2(fma)2(bipy)(DMF)o.5 prepared by a solvothermal route. Although there is some similarity between these structures, there are nevertheless important stmctural differences between them...

The fundamental task, in our opinion, is to correlate the principles and methods of the proposed synthesis with those of mechanochemical synthesis. Thus, besides the destruction processes and mechanochemical synthesis discussed in the literature, other lands of transformations sometimes occur as side reactions, or even as major processes. These include chemical fixation of small molecules (methyl chloride or butyl alcohol) on mechanically activated macromolecular backbones grafting of inorganic surfaces (quartz, metals, metallic oxides, inorganic salts, etc.) dispersed by vibratory milling on polymerized fragments synthesized from monomers present in the reaction medium, and activated by centers on the inorganic surface (14) and the possibility of some reactions (such as nitration), achieved so far on macromolecular supports and only as side reactions. 

The mechanochemical synthesis of polychelates in the system polyethylene terephthalate/ ethylenediamine/metallic salts confirms the idea... 

The methods of mechanochemical synthesis of various aluminates, including double compounds of alkaline, alkaline earth and transition metals, and aluminium, have been developed. The data on their synthesis, based on aluminium hydroxide, are presented according to this sequence. 

The authors [100] investigated mechanochemical synthesis of these perovskites using transition oxides in different oxidation state and lanthanum oxide or carbonate as initial compounds. The activated samples were then heated at temperatures above 500°C. The degree of interaction was shown to depend upon the oxidation degree of transition metal ions in oxides. The higher oxidation degree, i.e. the acidity of oxide, is preferable. 

Molchanov V.V., Maksimov G.M., Plyasova L.M., Goidin V.V., Kozhevnikov I.V. Mechanochemical synthesis of vanadates of alkali metals. Neorg. Materialy 1993 29 555-58. 

The tetrahedral [CoCl(Tppll,vle) reacts with L (L = hydroxypyridinone, hydroxypyridinethione, pyrone, and thiopy-rone) giving [Co(L)(Tpph,Me)]. Single-crystal X-ray studies show that the [Co(L)(TpPh Me)] is pentacoordinate with a general tendency toward square pyramidal geometry.138 The molecular structure of [Co(N03)(Tpph,Me)(THF)] has been also reported.139 Mechanochemical synthesis of [NiCl(Tpph,Me)] has been developed, which enabled the preparation of metal complexes of... 

Copyright (2010) Wiley. Used with permission from Frigid T, Reid DG, Halasz /, Stein RS, Dinnebier RE, Duer MJ. Ion- and liquid-assisted grinding improved mechanochemical synthesis of metal Organic frameworks reveals salt inclusion and anion templating. Angew Chem Int Ed... 

Finally, mechanochemical synthesis offers a solvent-free route for the preparation of MOFs by ball milling of starting components [23-28]. Sufficient amounts of pure material for broad-range testing can be easily obtained from this method. Furthermore, the solid-solid reaction typically produces quantitative yields and leads directly to products in powder form. Hence, the materials are ready for various applications without the need for time-consuming treatments. Mechanochemistry as an approach for the synthesis for one-, two-, and three-dimensional metal-organic compounds is currently employed by several groups, who mainly focus on the synthesis of new structures. 

Mechanochemical synthesis of metal oxides is conducted by several routes, the simplest one being the combination of different binary oxides. This method has been used to synthesize numerous materials including CrVO and LaVO as weU as... 

In this book, we briefly examine the different types of reactions and methods employed in the synthesis of inorganic solid materials. Besides the traditional ceramic procedures, we discuss precursor methods, combustion method, topochemical reactions, intercalation reactions, ion-exchange reactions, alkali-flux method, sol-gel method, mechanochemical synthesis, microwave synthesis, electrochemical methods, pyrosol process, arc and skull methods and high-pressure methods. Hydrothermal and solvothermal syntheses are discussed separately and also in sections dealing with specific materials. Superconducting cuprates and intergrowth structures are discussed in separate sections. Synthesis of nanomaterials is dealt with in some detail. Synthetic methods for metal borides, carbides, nitrides, fluorides, sili-cides, phosphides and chalcogenides are also outlined. 

An advantage of mechanochemical synthesis is the ease of preparation of powders that can otherwise be difficult to produce, such as those of the silicides and carbides. For example, most metal carbides are formed by the reaction between metals or metal hydrides and carbon at high temperatures (in some cases as high as 2000°C). Furthermore, some carbides and silicides have a narrow compositional range that is difficult to produce by other methods. A disadvantage is the incorporation of impurities from the mill and milling medium into the powder. 

Mechanochemical Synthesis of Metal-Organic Pharmaceutical Derivatives... 

Klimakow M, Klobes P, Thiinemann AF et al (2010) Mechanochemical synthesis of metal-organic frameworks a fast and facile approach toward quantitative yields and high specific surface areas. Chem Mater 22 5216-5221... 

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