Recent advances of Rh-based intermetallic nanomaterials for catalytic applications

Ceramics based on Mg2TiO4 (MTO) are widely used in numerous modern quantum electronic devices. The present paper deals with a study of cubic and tetragonal modifications of MTO. The band gap and electron state density of the cubic MTO are calculated for different distributions of Mg and Ti atoms over octahedral positions in the unit cell. Both random distributions of atoms over the octahedral positions and highly symmetric combinations are considered. The band gap as a function of the total energy of the unit cell is constructed. The band gap width increases at decreasing the free energy of a crystal. The highly symmetric distribution of atoms over the octahedral positions is shown to lead to a transition from cubic MTO to tetragonal syngony with a lower energy compared to an MTO cubic crystal with a random distribution of atoms over the octahedral positions. The band gap width for the cubic Mg2TiO4 with a random distribution of Mg and Ti atoms over the octahedral positions calculated by us using Vienna Ab initio Simulation Package (VASP) was 4.086 eV. The obtained results are in a good agreement with experimental data. The calculated band gap width for tetragonal MTO was 4.988 eV.

Liquid Metals in Catalysis for Energy Applications

Two-phonon processes have been used to study the crystalline structure of two mixed-crystal systems. The two-phonon spectra of ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}\mathrm{As}$ show coupled optical zone-edge phonons, which are GaAs-like, AlAs-like, and also combinations of GaAs-like and AlAs-like zone-edge phonons. The latter combination is not observed in $\mathrm{Ga}{\mathrm{P}}_{1\ensuremath{-}x}{\mathrm{As}}_{x}$, the other mixed-crystal system studied here, where the linewidth of the GaP-like Raman mode increases and the Raman intensity rapidly decreases with increasing As content. We explain these results qualitatively by assuming a random distribution of Ga and Al atoms in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Al}}_{x}\mathrm{As}$ crystals, and a distortion of the lattice structure as well as a departure from a random distribution of atoms in $\mathrm{Ga}{\mathrm{P}}_{1\ensuremath{-}x}{\mathrm{As}}_{x}$.

Chapter 15 - The key role of metal nanoparticle in metal organic frameworks of UiO family (MOFs) for the application of CO2 capture and heterogeneous catalysis

The zeolites are aluminosilicates with perfectly crystalline structure based on tetrahedral arrangements of silicon and aluminum. These materials present great potential for application in catalytic, adsorption and ion exchange processes. In addition, the zeolite crystallinity results in a highly stable material, with very organized micropores and network of channels. Zeolites have been widely used in chemical processes as heterogeneous catalysts, both in the research and development stage of technology and in applications already established in industry, such as the catalytic cracking of petroleum. The synthesis of this material occurs through the hydrothermal method, which consists on the steps of gel synthesis, crystallization at autogenous pressure, separation of the precipitated material and subsequent heat treatment to remove the structure directing agents. During preparation of the synthesis gel, the composition of the material to be generated can be changed, by varying the Si/Al ratio (important parameter for zeolites) or by incorporating other metals into the crystalline structure, for example. It is also possible to vary the amount of synthesis water, which changes the solubility of the medium and also the autogenous pressure in the subsequent phase. In the crystallization step, the time and temperature in which nucleation and crystal growth occurs can be manipulated, altering the size of the crystallites formed. Finally, in the heat treatment step, the textural properties and the crystallinity can be altered by modifying the temperature, heating rate and calcination time. The possibility of altering the physical-chemical properties of the zeolites makes them very versatile materials for application in catalysis, making it possible to obtain materials with characteristics close to the ideal for specific processes. In this sense, zeolitic materials have been used as catalysts with acidic activity (property generated in the material structure itself), as supports for certain active phases in chemical reactions and even as active supports in photochemical reactions. Therefore, the aim of this chapter is to discuss the synthesis of zeolites through the hydrothermal method, with a focus on the manipulation of the synthesis conditions and their consequences on the physicochemical properties and the implications for the applications in different catalytic processes. KeywordsZeolitesHydrothermal methodApplications

<div class="abstractSection abstractInFull">\n<p>We have constructed a novel porous pyrene-based organic cage, PyTC1, through the condensation reaction of cyclohexanediamine with 5,5′-(pyrene-1,6-diyl)diisophthalaldehyde. Single-crystal X-ray diffraction analysis reveals the effective intercage C–H...π interaction between cyclohexanediimine and pyrene segments. Such a soft intercage C–H...π interaction, rather than a classic <em>J</em>-aggregate with slipped π–π-stacking configuration, induced an unusual bathochromic shift of pyrene-based chromophore absorption from an ultraviolet region of PyTC1 in solution to the visible light region of PyTC1 in solid-state. This enabled heterogeneous visible light photocatalysis of aerobic hydroxylation of benzeneboronic acid derivatives. To the best of our knowledge, this is the first report that represents an absorption bathochromic shift caused by C–H...π interaction. Such phenomenon could endow visible-light-driven photocatalysis that originally could only be achieved using UV light with the same chromophore.</p>\n</div>\n<p> </p>

Matthias Beller, director of the Leibniz-Institut für Katalyse (LIKAT) in Rostock, Germany, provides an overview of the research in the institute since its establishment in 1952. Find out more about the institute's research in the LIKAT virtual issue. As a result of global population growth, climate change, and limited fossil resources, humanity faces significant challenges in the coming decades that can only be solved through new technologies and more sustainable production processes. Many of our current problems can be addressed by improved chemical transformations, which offer principle solutions for the future rather than being part of the problem, as is often seen today. In this respect, catalysis – the science of the acceleration of elementary chemical processes – allows reactions to take place in a way that spares resources, increases the desired product yields, avoids by-products, and reduces the specific energy requirements. Only by applying high-performance catalysts will it be possible to meet the global demand for efficient usage of all resources. Currently, around nine out of ten chemical products make use of catalysis during their manufacture. In addition, as well as in the field of chemistry, catalysts are also increasingly applied in the fields of life science, clean energy, and environmental protection. Thus, catalysis is a science that spans across a range of disciplines, and contributes to the process of finding solutions for the grand challenges of the 21st century. To further develop this field of science, it is clearly essential to form interdisciplinary collaborations between inorganic, organic, technical, theoretical, and physical chemistry, as well as nano- and material sciences, engineering, and process technology. More than 65 years of catalytic “know-how” forms the basis of the current expertise of the Leibniz-Institute for Catalysis (LIKAT). In 1952, two professors from the University of Rostock – Günther Rienäcker (heterogeneous catalysis) and Wolfgang Langenbeck (homogeneous catalysis) – came together to establish the Research Institute for Catalysis in Rostock. This became the first institute in Europe exclusively devoted to catalysis research, which soon became part of the Academy of Sciences of the GDR. In 1959, the two fields of catalysis research separated for what would be nearly 50 years. Homogeneous, namely organometallic catalysis, remained in Rostock and led to the creation of the Institute for Organic Catalysis Research. Heterogeneous catalysis moved to Berlin and became the focus of the Institute of Inorganic Catalysis Research. Later on, under the direction of Horst Pracejus in Rostock, fundamental work on asymmetric catalysis and organometallic chemistry was performed, while in Berlin research in various areas such as material sciences, heterogeneous catalysis, and organic synthesis continued. After the German Academy of Sciences was disbanded in 1991 as a result of the country's reunification, the Center for Heterogeneous Catalysis was created in 1992 in Berlin. Two years later this center joined with three other chemistry centers and formed the Institute for Applied Chemistry Berlin-Adlershof (ACA), which was directed initially by Bernhard Lücke and then Manfred Baerns. At the same time, the Rostock Catalysis Institute, led by Günther Oehme, became a state research institute of Mecklenburg–Western Pomerania after the closure of the Academy of Sciences. From 1992 to 1997, the Max-Planck-Society, through the establishment of two research groups, “Complex Catalysis” (Uwe Rosenthal) and “Asymmetric Catalysis” (Rüdiger Selke), contributed significantly to the stabilization and modernization of this institute. After a very positive evaluation of its research efforts under the direction of Matthias Beller by the German Council of Science and Humanities, the institute became part of the Leibniz Association on 01 January 2003. Nearly three years later, with the merger of the homogeneous and heterogeneous catalysis institutes from Berlin and Rostock, respectively, the Leibniz-Institute for Catalysis (LIKAT) was legally recognized. As an affiliated research institute of the University of Rostock, LIKAT has the legal form of a registered association, and as such includes a general membership meeting, a Board of Trustees, and a Scientific Advisory Council. In the group of Matthias Beller, “Applied Homogeneous Catalysis”, important aspects of molecular-defined and nanostructured catalysts, especially of transition-metal catalysts are investigated. Fundamental strategic aims of their research are the development of new environmentally benign redox catalysts and synthetic methodologies (aminations, carbonylations), as well as their application in industry. The transfer of results from model studies and mechanistic investigations to specific chemical products or processes is a particularly important aspect here. Methodologies which have been studied in the last years were carbonylation reactions, redox transformations, aminations, and applications towards alternative energy technologies. The current research in the “Heterogeneous Catalytic Processes” department (Sebastian Wohlrab) focuses largely on: (i) oxidation catalysis (selective oxidation, ammoxidation, acetoxylation, epoxidation, oxidative dehydrogenation) and (ii) the use of biomass for chemical and energy applications (conversion of triglycerides, fatty acids and glycerol, deoxygenation of biomass, use of carbon dioxide in chemical syntheses). Complementary to these works, in the group of Hans de Vries, various aspects of “Catalysis with Renewable Resources” are under investigation. More specifically, new catalytic reactions for the conversion of renewable resources into chemicals and fuels are developed. A broad spectrum of methods and techniques are applied for this purpose: From the synthesis of porous inorganic materials that are used as heterogeneous catalysts or as selective membranes, to the development of novel homogeneous transition-metal-based catalysts. Notably, catalytic reactions are optimized by the proper use of chemical technology such as flow chemistry, micro-structured reactors, and novel separation devices. Most of the research work described here is performed in specific projects with a dedicated lifetime, often in cooperation with industry or other academic partners. Apart from that, it is the long-term goal of the institute to contribute to effective catalyst design, based on a rational approach beyond trial and error. Undoubtedly, this requires a sound knowledge of the relationship between the structural features of a given catalyst and its role in the target transformation on a molecular basis. Such direct insight can be obtained by analyzing catalysts at work, under conditions as close as possible to those applied in a true catalytic process. These objectives are pursued in the department “Catalytic in situ Studies” of Angelika Brückner. This group focuses on the development, adaptation, and use of different analytic methods to monitor catalysts in homogeneous and heterogeneous catalytic reactions; this involves on-line detection of catalytic activity/selectivity (operando spectroscopy) in gas-solid, gas-liquid, liquid-solid and gas-liquid-solid systems, as well as during different stages in catalyst synthesis (in situ spectroscopy). An important element of their research activities is the in situ investigation of electron-transfer mechanisms in photo- and electrocatalytic reactions, such as hydrogen evolution by water splitting, which also includes the adaptation and development of suitable spectroelectrochemical methods. Over the past decade, special attention has been dedicated to simultaneous couplings of several operando methods. This not only saves time and money, but also gathers accessible information, and reduces errors that may arise from applying different experimental conditions in differently designed reaction cells. To complement these methodologies, in the department of “Catalyst Discovery and Reaction Engineering” (David Linke), high-throughput technologies, engineering tools, and mechanistic studies are explored. For the latter topic, the main aim is to elaborate strategies that enable the coupling of microscopic mechanistic (micro-kinetic) and physicochemical knowledge of complex heterogeneous reactions with macroscopic observations in chemical reactors (Evgenii Kondratenko). Recently, Jennifer Strunk was appointed professor at LIKAT and the University of Rostock. Her research aim is to supplement methods and technologies in catalysis with her existing knowledge in photocatalysis. Accordingly, the new department “Heterogeneous Photocatalysis” was created in 2017. In this department, the reduction of carbon dioxide to methanol or methane is studied, with the aim of implementing ecologically and economically feasible photocatalytic processes on an industrial scale. An important objective is to provide a detailed understanding of the underlying fundamental photophysical, catalytic, and electrochemical processes. This insight should serve as a basis for the development of improved photocatalysts and devices viable for large-scale applications. For more than 40 years, the institute has had a long-standing interest of the coordination chemistry of early and late transition-metal complexes in homogeneous catalysis. Among others, this tradition is continued in the department of Torsten Beweries, where different fundamental and applied aspects of titanium and zirconium metallacycles are investigated. Moreover, the activation of small molecules and dehydrogenation and dehydrocoupling reactions for hydrogen storage are investigated with late transition-metals. Finally, detailed mechanistic studies and catalyst developments for asymmetric hydrogenations are performed (Detlef Heller). Based on modern synthetic organometallic chemistry, a fundamental understanding of structure–activity relationships is a key issue. Industrially relevant hydrogenations and hydroformylations play an important role in the department of Armin Börner. Aside from the preparation of synthetic fragrances, odor-producing substances, and agrochemicals; in particular, hydroformylations are studied for the production of bulk aldehydes. The advantage of homogeneous catalysts in these processes lies in the potential to run the reaction in a highly chemoselective, regioselective, and even stereoselective manner. In the last decade, most of the work was dedicated to the synthesis of new and patent-free phosphorus(III) compounds, and their application in rhodium-catalyzed hydroformylations. Moreover, a better description of catalysis by investigating mechanistic aspects and observing the concentration of organometallic intermediates in a time-resolved manner is also pursued, using in situ HP-NMR and in situ FTIR spectroscopy. Based on these works, over 25 patent applications have been filed together with industrial partners (such as Evonik Industries) in the past five years (Detlef Selent). On the more fundamental side in the carbonylation department, reactions are applied for the preparation of various heterocycles (Xiao-Feng Wu), such as the synthesis of flavones, furanones, benzoxazinones, among others. Most recently, Paul Kamer joined the institute and the new group “Bio-inspired Homo- and Heterogeneous Catalysis” was created. The main objective of his team is the development of new bio-inspired catalytic processes. Currently, their major activity is in the field of ligand synthesis based on phosphorus donor atoms by rational design assisted by molecular modelling. Such ligand design is also supported by thorough mechanistic (in situ) studies of catalytic reactions to acquire insight into structure–activity relationships. Recently, three junior research groups have also started their independent scientific career in Rostock, working on “Catalytic Functionalization” (Jola Pospech), “Small Molecule Activation” (Christian Hering-Junghans), and “Polymer Chemistry and Catalysis” (Oscar Esteban Mejia Vargas). For a long time, the institute's approach has simply been the combination of application-oriented basic research and its technical implementation. However, at the beginning of the millennium this strategy was expanded to link homogeneous catalytic research with heterogeneous catalysis, and to develop further synergetic combinations of catalytic processes. In the coming years, this expertise will in particular be applied to the optimal usage of resources. In this way, we hope to further contribute to the development of green and practical catalysis, which continues to be important for the sustainable development of our societies.

Metal-organic frameworks-based heterogeneous single-atom catalysts (MOF-SACs) – Assessment and future perspectives

Review: 476 refs.

Review: 252 refs.

In this review, a brief survey is offered on the main nanotechnology synthetic approaches available to heterogeneous catalysis, and a few examples are provided of their usefulness for such applications. We start by discussing the use of colloidal, reverse micelle, and dendrimer chemistry in the production of active metal and metal oxide nanoparticles with well-defined sizes, shapes, and compositions, as a way to control the surface atomic ensembles available for selective catalysis. Next we introduce the use of sol-gel and atomic layer deposition chemistry for the production and modification of high-surface-area supports and active phases. Reference is then made to the more complex active sites that can be created or carved on such supports by using organic structure-directing agents. We follow with an examination of the ability to achieve multiple functionality in catalysis via the design of dumbbells, core@shell, and other complex nanostructures. Finally, we consider the mixed molecular-nanostructure approach that can be used to develop more demanding catalytic sites, by derivatizing the surface of solids or tethering or immobilizing homogeneous catalysts or other chemical functionalities. We conclude with a personal and critical perspective on the importance of fully exploiting the synergies between nanotechnology and surface science to optimize the search for new catalysts and catalytic processes.

50 years of Angewandte Chemie International Edition give me the opportunity to reflect on some of the highlights of chemical sciences over the past 25 years. I was greatly aided in this task by the rich diversity of high-quality reviews published in this journal during this period. Many of the developments summarized briefly in the following have been recognized by Nobel Prizes. Chemistry clearly has become a broader discipline, and its practitioners increasingly engage in interdisciplinary collaborations. While this trend has led to bold research contributions at the interfaces of biology, physics, and material sciences, chemistry has also seen refreshingly innovative developments in its core research. It has gained further stature and recognition as the central, enabling science which fertilizes the scientific progress in neighboring disciplines. Take the developments in NMR spectroscopy. Sophisticated two-, three-, and four-dimensional NMR pulse sequences have been developed, which have made NMR spectroscopy available for the elucidation of biological structures such as nucleic acids and proteins. In 1989 only two NMR structures were submitted to the Protein Data Bank (PDB); up until October 2010 there were more than 8600. NMR spectroscopy nicely complements X-ray crystallographic techniques, but is even closer to the real systems, as the structures are obtained in solution. Magnetic resonance imaging (MRI) of tumors and in vivo metabolic investigations have become essential tools in the diagnostics of human diseases. In drug discovery research, various NMR techniques, such as HSQC (heteronuclear single quantum coherence), are used to screen compound libraries for protein–ligand binding potency and for identifying binding epitopes. These methods are particularly valuable in the screening of fragment libraries. Solid-state NMR spectroscopy has started to complement the solution studies, and first applications in the elucidation of biological structures, such as membrane proteins and amyloid fibrils, have been reported. X-ray crystallography remains of eminent importance in biostructure elucidation, as is readily apparent from the PDB in which the total number of submitted X-ray structures has increased from less than 200 in 1985 to 11 400 in 2000 and approaching 60 000 in 2010. Prominent examples are the crystal structures of RNA polymerases, the ribosome, fatty acid synthase, and the nucleosome. After the first X-ray structure of a membrane protein, the photosynthetic reaction center, had been solved in 1982, an increasing number of membrane protein structures have been reported. Thus, an atomic-level understanding of the mechanism of selective ion and water transport across biological membranes became available when the structures of the potassium ion channel and the water channels, the aquaporins, were solved. The X-ray structure of the first G-protein coupled receptor (GPCR), bacteriorhodopsin, was reported in 1990 but recently, several other structures of GPCRs have been published. The increasing structural information on this class of membrane proteins promises to substantially aid the development of new medicines, as GPCRs are preferred targets for the development of pharmaceuticals for the treatment of various diseases. Nevertheless, the past two-and-a-half decades are clearly identifiable as the age of mass spectrometry (MS). Ion trap, electrospray ionization (ESI), and matrix-assisted laser desorption ionization (MALDI) MS techniques have enabled bold advances in many directions, from the screening of homogenous catalysts, to polymer and materials characterization, and protein identification and characterization. The fields of proteomics, that is, the mapping of the proteome, and, in a broader sense, systems biology would not have developed without these techniques. Ultrafast vibrational spectroscopy has been applied to the investigation of the hydration of nucleic acids, and Raman optical activity (ROA) is explored in the conformational analysis of biomolecules. Optical tweezers already find application in cell sorting. Vibrational and optical spectroscopic techniques, in particular time-resolved methods, benefit from the continuing advances in ultrafast laser technologies. As in many other research directions, in particular in chemical dynamics, spectroscopic techniques also thrive on the continuing increase in computing speed, power, and data-storage capacity. Computer simulations and theoretical calculations based on quantum mechanics and density functional theory are now broadly used in chemistry thanks to the availability of excellent software packages. With increasing computing capacity, the elucidation of the mechanisms of protein folding by using molecular dynamics simulations comes in reach. Computing capacity is also directly connected to progress in the emerging field of de novo protein design, which targets new enzyme catalysts and other proteins, such as novel chaperones, by a combination of in silico design and experimental selection and evolution methods. Chemical biology research has adopted the polymerase chain reaction (PCR) as a rapid method to multiply DNA in mutagenesis, genetic fingerprinting, and the cloning of genes, to name only a few applications. Decades after the structure of DNA had been revealed, chemists have indeed claimed back the genetic material for diverse study. Synthetic analogues, such as peptide nucleic acids (PNA) and nucleic acids incorporating different nucleobases and backbone scaffolds, have been prepared for antisense gene transfection, as well as for comparative study of the special features that made nature select DNA and RNA as genetic material. Yet the transfection process, that is, the introduction of nucleic acids into cells, remains problematic and this currently hampers efforts to use interference RNA (RNAi) for the control of gene activity in therapeutic applications. RNA cleavage by ribozymes was discovered. Selection methods have enabled the preparation of RNA aptamers with strong, selective ligand-binding properties. The molecular recognition properties of the major and minor groove of double-stranded DNA have been investigated in detail, which has aided the elucidation of the mechanism of transcription regulation by nuclear factors. Electron transfer across DNA has been studied as a mechanism for DNA cleavage and repair. Finally, the materials properties of tailor-made DNA fragments have been recognized and applied to the formation of nanostructures. Chemists have also addressed the other biopolymers and their assemblies. Synthetic bilayer membranes and model systems have been designed and their structural, transport, and recognition properties explored. Complex saccharides, glycopeptides, and glycolipids have been prepared with the aim, among others, of developing glyco-vaccines. β-Peptides show much higher biological stability than α-peptides as well as a distinct preference for adopting helical secondary structures. Research on catalytic antibodies has provided strong support to the Pauling proposal from the 1940s that transition-state stabilization is a major mechanism of enzymatic catalysis. From a technological perspective, a more important development has been the modification and stabilization of enzymes for use in the industrial-scale production of useful achiral and chiral chemical intermediates (“white biotechnology”). Other highlights strongly affecting chemical biology are the elucidation of the mechanisms of protein degradation in vertebrates by ubiquitination and subsequent disposal by the proteasome, of cell communication by NO, and of cellular signal transduction pathways. The invention of effective and safe medical drugs has greatly benefited from the insight gained into the regulation of signal transduction pathways by protein kinase mediated phosphorylation and protein phosphatase mediated dephosphorylation. There are more than 500 human kinases, as revealed by the completed human genome project. Creative chemical synthesis has succeeded in the preparation of highly selective protein kinase inhibitors, some of which are already on the market as effective antitumor drugs. This tremendous selectivity for one or a few kinases over all others deserves much appreciation, as it is achieved by molecules docking into the ATP–adenine binding pocket, which is common to all kinases. The attrition rate in modern preclinical drug development is currently being lowered through application of a multidimensional lead optimization approach. Target binding affinity and selectivity are optimized through judicious filling of chemical space, for which new chemical building blocks are invented, and this is increasingly guided by structure-based design strategies. At the same time, chemists optimize early on in lead generation important physicochemical properties such as bioavailability, pharmacokinetics, and metabolic stability, and prevent undesirable effects such as off-target binding, such as to cytochrome P450 enzymes, and hERG ion channel binding which causes cardiac side effects. This multidimensional approach to lead optimization is increasingly aided by computer-based predictive tools. Frequently, organofluorine groups are introduced to improve properties, and fluorine chemistry has seen an explosive growth in view of its many applications in the optimization of medical drugs and crop protection agents. One timely issue in drug discovery research is the energetically beneficial replacement of crystallographically observed water molecules at receptor active sites by ligand parts. Another major topic is the disruption of protein–protein interactions with small-molecule drugs, a possibility yet poorly developed. While nonpeptidic small-molecule drugs encounter strong competition by biologics such as therapeutic antibodies and peptides, their future remains bright, in particular since the problem of oral bioavailability of peptide drugs has not been generally solved. Surface plasmon resonance (SPR) should be mentioned as one of the enabling techniques for the high-throughput screening of the immense libraries that the pharmaceutical companies have assembled to find hits against new targets. DNA-chip and microarray technologies have profoundly changed gene identification and analysis. The development of chemical and biological probes for in vitro and in vivo analytics is at the forefront of current chemical biology research. They extend from green fluorescence protein (GFP) to molecules used as fluorescent or PET (positron emission tomography) biomarkers to detect deposited amyloid plaques, and fluorophores to monitor kinase activity. Amyloid plaque formation accompanies major diseases, such as Alzheimer’s disease, which increasingly affect the aging society. It is somewhat surprising that the number of academic chemistry research groups involved in creative brain research has remained quite small. This certainly will change in the coming decades. Similary, epigenetic gene regulation, such as by histone modification or DNA methylation, is easily predicted as an area of vigorous future chemical research. Supramolecular chemistry has been tremendously fueled by the Nobel Prizes awarded in 1987. Approximately one-third of all papers published in the premier chemical journals deal with supramolecular systems that link chemistry more than anything else to biology and materials sciences. Intermolecular interactions, such as cation–π interactions, anion–arene recognition, halogen bonding, and dipolar interactions, have been recognized and quantified in chemical and increasingly in biological systems. Although addressed, the impact of water as a solvent on supramolecular association remains to be fully understood. Fascinating novel host structures have emerged, such as covalent and self-assembled molecular container and capsules, featuring distinct inner-phase properties. The appealing structural motifs of molecular knots and Borromean rings have been realized in chemical systems. Unidirectional motion in molecular propellors, rotaxanes, and catenanes has been controlled in first examples but the realization of practical chemical motors is still a long way off. Much of this research is stimulated by biological examples, such as the ATPase and the muscle-moving actin–myosin system. The use of templates has greatly facilitated the synthesis of supramolecular systems. A particularly promising class of self-assembled systems are the metal–organic frameworks (MOFs)—crystalline porous lattices assembled by the judicious use of organic linkers connecting metal centers, with pores for gas storage, catalysis, and other applications. As an extension of combinatorial chemistry, which emerged vigorously at the beginning of the 1990s, dynamic combinatorial chemistry has been introduced as another original approach to the assembly of supramolecular systems. Since self-association modulates and generates new physical properties, the principles of supramolecular chemistry have particularly impacted functional materials research. For example, magnetism is a three-dimensional property and relies on the communication between molecular or ionic components. Self-association and controlled dimensionality are equally important for the formation of organic light-emitting diodes (OLEDs), field-effect transistors, photovoltaic devices, and solar cells, to name some of the major subjects of study. Materials research, driven by chemistry, has developed with admirable vigor and success over the past 25 years. Following the introduction of the first metallic polymers, electroluminescent conjugated polymers have attracted much interest. Oligomers have been intensively investigated as models for infinite polymers and for their intrinsic properties, such as for use in photovoltaic devices. But no new monomer has been introduced into the realm of bulk industrial polymers over the past 25 years; rather it is amazing how the properties of known polymers, such as polyurethanes and polyamides, have been enhanced and diversified through proper processing. Hyperbranched polymers and dendrimers have attracted much interest as new soft-matter materials, and ionic liquids promise new solutions in catalysis. Soft lithography has been established as an alternative to photolithographic processes to generate patterning and structuring on the micro- and even the nanoscale. The visualization of self-assembled molecules on surfaces has become possible by the introduction of scanning tunneling microscopy (STM) and atomic force microscopy (AFM), which also allow the study of single molecules. Heterogenous catalysis has greatly benefitted from the probe microscopy techniques including scanning near-field optical microscopy (SNOM), as they permit the monitoring of elementary steps in the catalytic processes. A plethora of new solid catalyst materials have been prepared, mainly originating from advances in inorganic solid-state chemistry. New methods for the preparation of ceramic materials have widened their range of application. Strong interest has also developed in biocompatible materials for applications in medical devices and in body-tissue replacement. But the most original discoveries in materials research deal with the element carbon. The first observation and the subsequent practical synthesis of buckminsterfullerene C60 and higher fullerenes led to the frenzied development of the chemistry of these molecular carbon allotropes, which continues today with the introduction of soluble fullerenes as components in photovoltaic and solar-cell devices. The insoluble carbon nanotubes (CNTs) raised exceptional interest owing to their mechanical properties, such as special hardness, flexibility, and stability, and also their electronic properties. In parallel, metal oxide and metal sulfide based nanotubes have been discovered. All these developments are rivaled by the recent discovery of a method to prepare single layers of graphite, graphene, a material with fascinating properties and great promise for future technological applications. Many of the new materials have been produced as nanoparticles of defined size and shape, and a great variety of organic and/or inorganic matter that has been downsized to the nanometer scale displays special functions and properties. Other classes of compounds, such as the polyoxalates and other transition-metal complexes, have been expanded to defined clusters of multi-nanometer size. Nanoparticles are used not only as additives in composite materials, but they are also exploited as catalysts, in membranes and separation devices, as vehicles for gene transfection, in nano-electronics, and in diverse biomedical applications. In addition to STM and AFM, transmission electron microscopy (TEM) is one of the preferred methods for their characterization. Concerns about the safety of nanoparticles are being properly addressed in ongoing studies. Advances in analytical separation techniques have strongly impacted synthetic organic chemistry. For enantiomer separations by HPLC, highly efficient chiral stationary phases are now available. The performance of chromatographic separations has been further extended by the application of very high pressure and supercritical fluids. Reaction workups have been facilitated by the introduction of fluorous phases and transformations miniaturized by using microfluidics and microdroplets. New synthetic protocols continue to be tested and applied to the total syntheses of challenging complex natural products with fascinating structures. The efficiency of the transformations has been enhanced by the introduction of rapid high-yielding, atom-economical click reactions. The number of steps in multistep syntheses has been reduced through the introduction of multicomponent reactions and cascade transformations and by eliminating the need for protecting groups. Environmental considerations increasingly come into play in what has been coined “green chemistry”, and an example is the replacement of toxic metal salts with hydrogen peroxide or dioxygen in oxidation reactions. Transition-metal catalysis has profited from amazing advances in the development of new ligands such as N-heterocyclic carbenes (NHCs). Yet, a number of important transformations still await a solution, as exemplified by the selective CH activation of alkanes. Also, efficient and economical activation of CO2 could provide a new C1 component in the chemical production chain. The tremendous success in developing efficient protocols for asymmetric catalysis testifies to the high creativity of synthetic chemists. Organocatalysis has emerged as another successful concept to selectively accelerate desired transformations. Palladium-catalyzed cross-coupling reactions have moved rapidly from academic laboratories to industrial production. Increasingly, cross-couplings generate bonds not only between C(sp) and C(sp2) but also at C(sp3) centers, although there is still room for innovation in this direction. CC bond formation by these transformations has been nicely complemented by similar protocols for efficient CO and CN bond formation. The discovery of the olefin metathesis reaction has had a tremendous impact. While this reaction was initially viewed predominantly as a new approach to polymers, the access to stable and versatile catalysts has fueled its broad application in organic synthesis. In particular ring-closing metathesis (RCM), starting from olefins and increasingly alkynes, has provided a new approach for the formation of small-, medium- and large-sized rings. For macrocyclizations, RCM is replacing most other transformations as the method of choice. Yet, a general solution for the selective formation of either cis- or trans-configured olefins has not yet been found. The understanding of chemical bonding and its repertoire have greatly expanded, opening up new, often surprising structural opportunities, such as for silicon chemistry. Connecting transition metals and main-group elements by multiple bonds created a new interface between inorganic solid-state chemistry and organometallic chemistry. Also, the formation of multiple bonds between higher main-group elements has generated unprecedented complex and ligand structures. Such fundamental advances in chemistry open up new structural space full of surprises and opportunities. It is hoped that, in times of increasingly mission- and application-oriented funding programs, the support for excellent basis research will remain strong to enable true discovery. Basic research is vital for the healthy future of chemistry. Chemistry has clearly signaled its commitment to contribute sustainable solutions for the major challenges related to the changes in global energy resources and to climate change. The mechanisms of atmospheric changes have been identified by chemists, and fluorocarbons, responsible for the depletion of the ozone layer, have been replaced. Efficient homogenous and heterogenous catalysis is the best and most natural contribution of chemists to ecologically sustainable and economical chemical production. The desirable elimination of stoichiometric amounts of side products, in particular inorganic salts, rests on the development innovative new methods development. Fuel cells, batteries and energy-storage systems, solar-energy-harvesting devices such as dye-sensitized solar cells, organic light-emitting diodes (OLEDs) with greatly reduced energy consumption, new insulating materials for construction, green biotechnology to meet the demands for food for our growing global population, sufficient clean water for everyone: these and many other goals will become reality through chemical research. Therefore, I am very optimistic that chemistry will remain the central enabling science in the future. This requires, however, that chemistry continues to strengthen its core research disciplines—synthesis, reactivity, stereochemistry, physical analysis, analytics—since chemists educated in these disciplines are the most valuable contributors to interfacial, interdisciplinary research and technology. I end with a few questions challenging our future teaching in the classroom and beyond: How can we continue to attract the best talent into chemistry? How will we communicate the of that chemical research has generated How we to the core of chemistry in times of interdisciplinary I am of optimistic that we will find solutions to these

Regulating the surface of nanoceria and its applications in heterogeneous catalysis

Fermentation, thermochemical and catalytic processes in the transformation of biomass through efficient biorefineries

Since the 1980s [1,2], colloidal systems such as microemulsions (ME) have been widely investigated, especially for the synthesis of nanomaterials for various applications.[...]