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Journal ArticleDOI

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: The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Abstract: The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

2,582 citations

Journal ArticleDOI
TL;DR: In this paper, the chemical, thermal and mechanical stabilities of MOFs, in particular with catalytic uses in mind, are discussed, and future directions of study for the production of highly stable MOFs are briefly discussed.
Abstract: The construction of thousands of well-defined, porous, metal–organic framework (MOF) structures, spanning a broad range of topologies and an even broader range of pore sizes and chemical functionalities, has fuelled the exploration of many applications. Accompanying this applied focus has been a recognition of the need to engender MOFs with mechanical, thermal and/or chemical stability. Chemical stability in acidic, basic and neutral aqueous solutions is important. Advances over recent years have made it possible to design MOFs that possess different combinations of mechanical, thermal and chemical stability. Here, we review these advances and the associated design principles and synthesis strategies. We focus on how these advances may render MOFs effective as heterogeneous catalysts, both in chemically harsh condensed phases and in thermally challenging conditions relevant to gas-phase reactions. Finally, we briefly discuss future directions of study for the production of highly stable MOFs. Metal–organic frameworks (MOFs) have shown promise in a broad range of applications, including catalysis. In this Review, the chemical, thermal and mechanical stabilities of MOFs, in particular with catalytic uses in mind, are discussed.

1,332 citations

Journal ArticleDOI
TL;DR: This Review considers several aspects of the most prominent sustainable organicsolvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solVents, liquid polymers, and renewable solvent, giving a more complete picture of the current status of sustainable solvent research and development.
Abstract: Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, although how a substance is deployed is as important to sustainability as what it is made from. In this Review, we consider several aspects of the most prominent sustainable organic solvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solvents, liquid polymers, and renewable solvents. We examine not only the performance of each class of solvent within the context of the...

1,051 citations

Journal ArticleDOI
TL;DR: The aim of this review article is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemistry.
Abstract: The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

908 citations

Journal ArticleDOI
23 May 2016
TL;DR: A review of general purpose solvent selection guides can be found in this paper, highlighting their similarities and differences and how they can be used to enhance the greenness of chemical processes, particularly in laboratory organic synthesis and the pharmaceutical industry.
Abstract: Driven by legislation and evolving attitudes towards environmental issues, establishing green solvents for extractions, separations, formulations and reaction chemistry has become an increasingly important area of research Several general purpose solvent selection guides have now been published with the aim to reduce use of the most hazardous solvents This review serves the purpose of explaining the role of these guides, highlighting their similarities and differences How they can be used most effectively to enhance the greenness of chemical processes, particularly in laboratory organic synthesis and the pharmaceutical industry, is addressed in detail

756 citations

References
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TL;DR: A review of the state of the art in the use of alternative reaction media for green, sustainable organic synthesis is presented in this article, where a novel and effective method for the immobilisation of enzymes as cross-linked enzyme aggregates (CLEAs) is discussed and a combi CLEA, containing two enzymes, for the one-pot conversion of benzaldehyde to S-mandelic acid is reported.

1,392 citations

Journal ArticleDOI
TL;DR: Cyclodextrins, because of their continuing ability to find several novel applications in drug delivery, are expected to solve many problems associated with the delivery of different novel drugs through different delivery routes.
Abstract: The purpose of this review is to discuss and summarize some of the interesting findings and applications of cyclodextrins (CDs) and their derivatives in different areas of drug delivery, particularly in protein and peptide drug delivery and gene delivery. The article highlights important CD applications in the design of various novel delivery systems like liposomes, microspheres, microcapsules, and nanoparticles. In addition to their well-known effects on drug solubility and dissolution, bioavailability, safety, and stability, their use as excipients in drug formulation are also discussed in this article. The article also focuses on various factors influencing inclusion complex formation because an understanding of the same is necessary for proper handling of these versatile materials. Some important considerations in selecting CDs in drug formulation such as their commercial availability, regulatory status, and patent status are also summarized. CDs, because of their continuing ability to find several novel applications in drug delivery, are expected to solve many problems associated with the delivery of different novel drugs through different delivery routes.

1,135 citations

Journal ArticleDOI
TL;DR: In this review different examples from 2001-2008 are highlighted, which have been performed at least on a kilogram scale in the chemical and pharmaceutical industries.
Abstract: Palladium-catalyzed coupling reactions have become a central tool for the synthesis of biologically active compounds both in academia and industry. Most of these transformations make use of easily available substrates and allow for a shorter and more selective preparation of substituted arenes and heteroarenes compared to non-catalytic pathways. Notably, molecular-defined palladium catalysts offer high chemoselectivity and broad functional group tolerance. Considering these advantages, it is not surprising that several palladium-catalyzed coupling reactions have been implemented in the last decade into the industrial manufacture of pharmaceuticals and fine chemicals. In this review different examples from 2001-2008 are highlighted, which have been performed at least on a kilogram scale in the chemical and pharmaceutical industries.

1,121 citations

Journal ArticleDOI
TL;DR: A survey of the classical works in mechanochemistry is given and the key mechanochemical phenomena into perspective with recent results from atomic force microscopy and quantum molecular dynamics simulations are put into perspective.
Abstract: Regarding the activation of chemical reactions, today’s chemist is used to thinking in terms of thermochemistry, electrochemistry, and photochemistry, which is reflected in the organization and content of the standard physical chemistry textbooks. The fourth way of chemical activation, mechanochemistry, is usually less well-known. The purpose of the present review is to give a survey of the classical works in mechanochemistry and put the key mechanochemical phenomena into perspective with recent results from atomic force microscopy and quantum molecular dynamics simulations. A detailed historical account on the development of mechanochemistry, with an emphasis on the mechanochemistry of solids, was recently given by Boldyrev and Tkáčová.1 The first written document of a mechanochemical reaction is found in a book by Theophrastus of Ephesus (371-286 B.C.), a student of Aristotle, “De Lapidibus” or “On stones”. If native cinnabar is rubbed in a brass mortar with a brass pestle in the presence of vinegar, metallic mercury is obtained. The mechanochemical reduction probably follows the reaction:1-3 * To whom correspondence should be addressed. Telephone: ++49-89-289-13417. Fax: ++49-89-289-13416. E-mail: martin.beyer@ch.tum.de (M.K.B.); Telephone: ++49-89-12651417. Fax: ++49-89-1265-1480. E-mail: clausen-schaumann@ fhm.edu (H.C.-S.). † Technische Universität München. ‡ Institut für Strahlenschutz. § Current address: Munich University of Applied Sciences. HgS + Cu f Hg + CuS (1) Volume 105, Number 8

1,062 citations