Mechanochemistry: opportunities for new and cleaner synthesis
TL;DR: Concentrating on recent advances, this article covers industrial aspects, inorganic materials, organic synthesis, cocrystallisation, pharmaceutical aspects, metal complexes, supramolecular aspects and characterization methods.
Abstract: The aim of this critical review is to provide a broad but digestible overview of mechanochemical synthesis, i.e. reactions conducted by grinding solid reactants together with no or minimal solvent. Although mechanochemistry has historically been a sideline approach to synthesis it may soon move into the mainstream because it is increasingly apparent that it can be practical, and even advantageous, and because of the opportunities it provides for developing more sustainable methods. Concentrating on recent advances, this article covers industrial aspects, inorganic materials, organic synthesis, cocrystallisation, pharmaceutical aspects, metal complexes (including metal–organic frameworks), supramolecular aspects and characterization methods. The historical development, mechanistic aspects, limitations and opportunities are also discussed (314 references).
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TL;DR: In this article, the preparation, characterization, and application of perovskite oxides in heterogeneous catalysis is discussed. But the authors focus on the preparation and characterization of materials with desired textural structure and physicochemical properties.
Abstract: Perovskite oxides with formula ABO3 or A2BO4 are a very important class of functional materials that exhibit a range of stoichiometries and crystal structures. Because of the structural features, they could accommodate around 90% of the metallic natural elements of the Periodic Table that stand solely or partially at the A and/or B positions without destroying the matrix structure, offering a way of correlating solid state chemistry to catalytic properties. Moreover, their high thermal and hydrothermal stability enable them suitable catalytic materials either for gas or solid reactions carried out at high temperatures, or liquid reactions carried out at low temperatures. In this review, we addressed the preparation, characterization, and application of perovskite oxides in heterogeneous catalysis. Preparation is an important issue in catalysis by which materials with desired textural structure and physicochemical property could be achieved; characterization is the way to explore and understand the textura...
657 citations
TL;DR: This review article provides a comprehensive overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels-Alder reactions, oxidations, reductions, halogenation/aminohalogenation, etc.
Abstract: Recently, mechanical milling using a mixer mill or planetary mill has been fruitfully utilized in organic synthesis under solvent-free conditions This review article provides a comprehensive overview of various solvent-free mechanochemical organic reactions, including metal-mediated or -catalyzed reactions, condensation reactions, nucleophilic additions, cascade reactions, Diels–Alder reactions, oxidations, reductions, halogenation/aminohalogenation, etc The ball milling technique has also been applied to the synthesis of calixarenes, rotaxanes and cage compounds, asymmetric synthesis as well as the transformation of biologically active compounds
639 citations
TL;DR: The synthesized COFs were successfully delaminated using a simple, safe, and environmentally friendly mechanical grinding route to transform into covalent organic nanosheets (CONs) and were well characterized via transmission electron microscopy and atomic force microscopy.
Abstract: A series of five thermally and chemically stable functionalized covalent organic frameworks (COFs), namely, TpPa-NO2, TpPa-F4, TpBD-(NO2)2, TpBD-Me2, and TpBD-(OMe)2 were synthesized by employing the solvothermal aldehyde-amine Schiff base condensation reaction. In order to complete the series, previously reported TpPa-1, TpPa-2, and TpBD have also been synthesized, and altogether, eight COFs were fully characterized through powder X-ray diffraction (PXRD), Fourier transform IR (FT-IR) spectroscopy, 13C solid-state NMR spectroscopy, and thermogravimetric analysis. These COFs are crystalline, permanently porous, and stable in boiling water, acid (9 N HCl), and base (3 N NaOH). The synthesized COFs (all eight) were successfully delaminated using a simple, safe, and environmentally friendly mechanical grinding route to transform into covalent organic nanosheets (CONs) and were well characterized via transmission electron microscopy and atomic force microscopy. Further PXRD and FT-IR analyses confirm that the...
620 citations
TL;DR: An up-to-date survey of the most promising novel synthetic routes, i.e., electrochemical, microwave, mechanochemical, spray drying and flow chemistry synthesis, and the essential topic of downstream processes, especially for large scale synthesis, is critically reviewed.
Abstract: The potential commercial applications for metal organic frameworks (MOFs) are tantalizing. To address the opportunity, many novel approaches for their synthesis have been developed recently. These strategies present a critical step towards harnessing the myriad of potential applications of MOFs by enabling larger scale production and hence real-world applications. This review provides an up-to-date survey ( references) of the most promising novel synthetic routes, i.e., electrochemical, microwave, mechanochemical, spray drying and flow chemistry synthesis. Additionally, the essential topic of downstream processes, especially for large scale synthesis, is critically reviewed. Lastly we present the current state of MOF commercialization with direct feedback from commercial players.
558 citations
TL;DR: In this review the success of numerous pharmaceutical cocrystals for the improvement of the solubility and dissolution rates of poorly soluble drugs is demonstrated using various examples taken from the literature.
499 citations
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TL;DR: In this paper, a structure refinement method was described which does not use integrated neutron powder intensities, single or overlapping, but employs directly the profile intensities obtained from step-scanning measurements of the powder diagram.
Abstract: A structure refinement method is described which does not use integrated neutron powder intensities, single or overlapping, but employs directly the profile intensities obtained from step-scanning measurements of the powder diagram. Nuclear as well as magnetic structures can be refined, the latter only when their magnetic unit cell is equal to, or a multiple of, the nuclear cell. The least-squares refinement procedure allows, with a simple code, the introduction of linear or quadratic constraints between the parameters.
14,360 citations
TL;DR: In this paper, a highly porous metal coordination polymer [Cu3(TMA)2(H2O)3]n (where TMA is benzene-1,3,5-tricarboxylate) was formed in 80 percent yield.
Abstract: Although zeolites and related materials combine nanoporosity with high thermal stability, they are difficult to modify or derivatize in a systematic way. A highly porous metal coordination polymer [Cu3(TMA)2(H2O)3]n (where TMA is benzene-1,3,5-tricarboxylate) was formed in 80 percent yield. It has interconnected [Cu2(O2CR)4] units (where R is an aromatic ring), which create a three-dimensional system of channels with a pore size of 1 nanometer and an accessible porosity of about 40 percent in the solid. Unlike zeolites, the channel linings can be chemically functionalized; for example, the aqua ligands can be replaced by pyridines. Thermal gravimetric analysis and high-temperature single-crystal diffractometry indicate that the framework is stable up to 240 degreesC.
5,061 citations
TL;DR: Transition-Metal-Free Reactions, Alkynylation of Heterocycles, and Synthesis of Electronic and Electrooptical Molecules: A Review.
Abstract: 3.7. Palladium Nanoparticles as Catalysts 888 3.8. Other Transition-Metal Complexes 888 3.9. Transition-Metal-Free Reactions 889 4. Applications 889 4.1. Alkynylation of Arenes 889 4.2. Alkynylation of Heterocycles 891 4.3. Synthesis of Enynes and Enediynes 894 4.4. Synthesis of Ynones 896 4.5. Synthesis of Carbocyclic Systems 897 4.6. Synthesis of Heterocyclic Systems 898 4.7. Synthesis of Natural Products 903 4.8. Synthesis of Electronic and Electrooptical Molecules 906
2,522 citations
2,308 citations
TL;DR: A set of general guidelines for structure refinement using the Rietveld (whole profile) method has been formulated by the International Union of Crystallography Commission on Powder Diffraction.
Abstract: A set of general guidelines for structure refinement using the Rietveld (whole-profile) method has been formulated by the International Union of Crystallography Commission on Powder Diffraction. The practical rather than the theoretical aspects of each step in a typical Rietveld refinement are discussed with a view to guiding newcomers in the field. The focus is on X-ray powder diffraction data collected on a laboratory instrument, but features specific to data from neutron (both constant-wavelength and time-of-flight) and synchrotron radiation sources are also addressed. The topics covered include (i) data collection, (ii) background contribution, (iii) peak-shape function, (iv) refinement of profile parameters, (v) Fourier analysis with powder diffraction data, (vi) refinement of structural parameters, (vii) use of geometric restraints, (viii) calculation of e.s.d.'s, (ix) interpretation of R values and (x) some common problems and possible solutions.
1,808 citations