Showing papers in "Topics in Current Chemistry in 2016"
TL;DR: This chapter discusses in each cases the chemical and mechanistic background, the kinetics of the reactions and the biological applicability together with the limiting factors, with a focus on those that have shown broad utility in biological systems.
Abstract: In the last decade and a half, numerous bioorthogonal reactions have been developed with a goal to study biological processes in their native environment, i.e., in living cells and animals. Among them, the photo-triggered reactions offer several unique advantages including operational simplicity with the use of light rather than toxic metal catalysts and ligands, and exceptional spatiotemporal control through the application of an appropriate light source with pre-selected wavelength, light intensity and exposure time. While the photoinduced reactions have been studied extensively in materials research, e.g., on macromolecular surface, the adaptation of these reactions for chemical biology applications is still in its infancy. In this chapter, we review the recent efforts in the discovery and optimization the photo-triggered bioorthogonal reactions, with a focus on those that have shown broad utility in biological systems. We discuss in each cases the chemical and mechanistic background, the kinetics of the reactions and the biological applicability together with the limiting factors.
269 citations
TL;DR: This chapter covers core aspects of the strain-promoted reaction of cycloalkynes with azides, as well as tools to achieve further reaction acceleration by means of modulation ofcycloalkyne structure, nature of azide, and choice of solvent.
Abstract: A nearly forgotten reaction discovered more than 60 years ago—the cycloaddition of a cyclic alkyne and an organic azide, leading to an aromatic triazole—enjoys a remarkable popularity. Originally discovered out of pure chemical curiosity, and dusted off early this century as an efficient and clean bioconjugation tool, the usefulness of cyclooctyne–azide cycloaddition is now adopted in a wide range of fields of chemical science and beyond. Its ease of operation, broad solvent compatibility, 100 % atom efficiency, and the high stability of the resulting triazole product, just to name a few aspects, have catapulted this so-called strain-promoted azide–alkyne cycloaddition (SPAAC) right into the top-shelf of the toolbox of chemical biologists, material scientists, biotechnologists, medicinal chemists, and more. In this chapter, a brief historic overview of cycloalkynes is provided first, along with the main synthetic strategies to prepare cycloalkynes and their chemical reactivities. Core aspects of the strain-promoted reaction of cycloalkynes with azides are covered, as well as tools to achieve further reaction acceleration by means of modulation of cycloalkyne structure, nature of azide, and choice of solvent.
251 citations
TL;DR: This chapter first emphasizes the recent progress on the Ni-catalyzed alkylation, arylation/vinylation, and acylation of alkyl electrophiles, and the coupling of aryl halides with other C(sp2)–electrophiles.
Abstract: The Ni-catalyzed reductive coupling of alkyl/aryl with other electrophiles has evolved to be an important protocol for the construction of C–C bonds. This chapter first emphasizes the recent progress on the Ni-catalyzed alkylation, arylation/ vinylation, and acylation of alkyl electrophiles. A brief overview of CO2 fixation is also addressed. The chemoselectivity between the electrophiles and the reactivity of the alkyl substrates will be detailed on the basis of different Nicatalyzed conditions and mechanistic perspective. The asymmetric formation of C(sp3)–C(sp2) bonds arising from activated alkyl halides is next depicted followed by allylic carbonylation. Finally, the coupling of aryl halides with other C(sp2)– electrophiles is detailed at the end of this chapter.
211 citations
TL;DR: This chapter addresses the development of inorganic phosphor materials capable of converting the near UV or blue radiation emitted by a light emitting diode to visible radiation that can be suitably combined to yield white light.
Abstract: This chapter addresses the development of inorganic phosphor materials capable of converting the near UV or blue radiation emitted by a light emitting diode to visible radiation that can be suitably combined to yield white light. These materials are at the core of the new generation of solid-state lighting devices that are emerging as a crucial clean and energy saving technology. The chapter introduces the problem of white light generation using inorganic phosphors and the structure-property relationships in the broad class of phosphor materials, normally containing lanthanide or transition metal ions as dopants. Radiative and non-radiative relaxation mechanisms are briefly described. Phosphors emitting light of different colors (yellow, blue, green, and red) are described and reviewed, classifying them in different chemical families of the host (silicates, phosphates, aluminates, borates, and non-oxide hosts). This research field has grown rapidly and is still growing, but the discovery of new phosphor materials with optimized properties (in terms of emission efficiency, chemical and thermal stability, color, purity, and cost of fabrication) would still be of the utmost importance.
174 citations
TL;DR: A deeper insight is given into the photophysical properties of this material class and how the emission properties depend on molecular and host rigidity and it is shown that with molecular optimization a significant improvement of selected emission properties can be achieved.
Abstract: Molecules that exhibit thermally activated delayed fluorescence (TADF) represent a very promising emitter class for application in electroluminescent devices since all electrically generated excitons can be transferred into light according to the singlet harvesting mechanism. Cu(I) compounds are an important class of TADF emitters. In this contribution, we want to give a deeper insight into the photophysical properties of this material class and demonstrate how the emission properties depend on molecular and host rigidity. Moreover, we show that with molecular optimization a significant improvement of selected emission properties can be achieved. From the discussed materials, we select one specific dinuclear complex, for which the two Cu(I) centers are four-fold bridged to fabricate an organic light emitting diode (OLED). This device shows the highest efficiency (of 23 % external quantum efficiency) reported so far for OLEDs based on Cu(I) emitters.
132 citations
TL;DR: High-definition (spectral) imaging appears as the main driving force of the current trend for new synchrotron techniques for research on cultural and natural heritage materials.
Abstract: Synchrotrons have provided significant methods and instruments to study ancient materials from cultural and natural heritages. New ways to visualise (surfacic or volumic) morphologies are developed on the basis of elemental, density and refraction contrasts. They now apply to a wide range of materials, from historic artefacts to paleontological specimens. The tunability of synchrotron beams owing to the high flux and high spectral resolution of photon sources is at the origin of the main chemical speciation capabilities of synchrotron-based techniques. Although, until recently, photon-based speciation was mainly applicable to inorganic materials, novel developments based, for instance, on STXM and deep UV photoluminescence bring new opportunities to study speciation in organic and hybrid materials, such as soaps and organometallics, at a submicrometric spatial resolution over large fields of view. Structural methods are also continuously improved and increasingly applied to hierarchically structured materials for which organisation results either from biological or manufacturing processes. High-definition (spectral) imaging appears as the main driving force of the current trend for new synchrotron techniques for research on cultural and natural heritage materials.
127 citations
TL;DR: Recent insights regarding the operational mechanism, breakthroughs in the development of scalable and adaptable solution-based methods for cost-efficient fabrication, and successful efforts toward the realization of LEC devices with improved efficiency and stability are presented.
Abstract: The light-emitting electrochemical cell (LEC) is an area-emitting device, which features a complex turn-on process that ends with the formation of a p-n junction doping structure within the active material. This in-situ doping transformation is attractive in that it promises to pave the way for an unprecedented low-cost fabrication of thin and light-weight devices that present efficient light emission at low applied voltage. In this review, we present recent insights regarding the operational mechanism, breakthroughs in the development of scalable and adaptable solution-based methods for cost-efficient fabrication, and successful efforts toward the realization of LEC devices with improved efficiency and stability.
118 citations
TL;DR: Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions.
Abstract: Proton-coupled electron transfers (PCETs) are unconventional redox processes in which both protons and electrons are exchanged, often in a concerted elementary step. While PCET is now recognized to play a central a role in biological redox catalysis and inorganic energy conversion technologies, its applications in organic synthesis are only beginning to be explored. In this chapter, we aim to highlight the origins, development, and evolution of the PCET processes most relevant to applications in organic synthesis. Particular emphasis is given to the ability of PCET to serve as a non-classical mechanism for homolytic bond activation that is complimentary to more traditional hydrogen atom transfer processes, enabling the direct generation of valuable organic radical intermediates directly from their native functional group precursors under comparatively mild catalytic conditions. The synthetically advantageous features of PCET reactivity are described in detail, along with examples from the literature describing the PCET activation of common organic functional groups.
109 citations
TL;DR: The low-cost, natural abundance, and low toxicity of iron prompted its very recent application in organometallic C–H activation catalysis.
Abstract: Iron-catalyzed C–H activation has recently emerged as an increasingly powerful tool for the step-economical transformation of unreactive C–H bonds. Particularly, the recent development of low-valent iron catalysis has set the stage for novel C–H activation strategies via chelation assistance. The low-cost, natural abundance, and low toxicity of iron prompted its very recent application in organometallic C–H activation catalysis. An overview of the use of iron catalysis in C–H activation processes is summarized herein up to May 2016.
102 citations
TL;DR: This chapter highlights the state-of-the-art emitters in terms of efficiency and stability in LEEC devices, highlighting blue, green, yellow/orange, red and white devices, and provides an outlook to the future of LEECs.
Abstract: Cationic iridium(III) complexes represent the single largest class of emitters used in light emitting electrochemical cells (LEECs). In this chapter, we highlight the state-of-the-art emitters in terms of efficiency and stability in LEEC devices, highlighting blue, green, yellow/orange, red and white devices, and provide an outlook to the future of LEECs.
94 citations
TL;DR: These impressive demonstrations reveal that d8 metal complexes are promising candidates as phosphorescent materials for OLED applications in displays as well as in solid-state lighting in the future.
Abstract: Encouraging efforts on the design of high-performance organic materials and smart architecture during the past two decades have made organic light-emitting device (OLED) technology an important competitor for the existing liquid crystal displays. Particularly, the development of phosphorescent materials based on transition metals plays a crucial role for this success. Apart from the extensively studied iridium(III) complexes with d6 electronic configuration and octahedral geometry, the coordination-unsaturated nature of d8 transition metal complexes with square-planar structures has been found to provide intriguing spectroscopic and luminescence properties. This article briefly summarizes the development of d8 platinum(II) and gold(III) complexes and their application studies in the fabrication of phosphorescent OLEDs. An in-depth understanding of the nature of the excited states has offered a great opportunity to fine-tune the emission colors covering the entire visible spectrum as well as to improve their photophysical properties. With good device engineering, high performance vacuum-deposited OLEDs with external quantum efficiencies (EQEs) of up to 30 % and solution-processable OLEDs with EQEs of up to 10 % have been realized by modifying the cyclometalated or pincer ligands of these metal complexes. These impressive demonstrations reveal that d8 metal complexes are promising candidates as phosphorescent materials for OLED applications in displays as well as in solid-state lighting in the future.
TL;DR: This work provides a personal perspective on recent applications and new frontiers in sampling modalities, data processing, and instrumentation in Raman spectroscopy of cultural heritage materials.
Abstract: Rooted in the long tradition of Raman spectroscopy of cultural heritage materials, in this work we provide a personal perspective on recent applications and new frontiers in sampling modalities, data processing, and instrumentation.
TL;DR: This chapter presents recent advances expanding the scope of precursor reactivity and new biomedical methodology based on bioorthogonal tetrazine chemistry and highlights novel applications for different kinds of biomolecules, including nucleic acid, protein, antibodies, lipids, glycans, and bioactive small molecules in the areas of imaging, detection, and diagnostics.
Abstract: Bioorthogonal reactions have been widely used over the last 10 years for imaging, detection, diagnostics, drug delivery, and biomaterials. Tetrazine reactions are a recently developed class of inverse electron-demand Diels–Alder reactions used in bioorthogonal applications. Given their rapid tunable reaction rate and highly fluorogenic properties, tetrazine bioorthogonal reactions have come to be considered highly attractive tools for elucidating biological functions and messages in vitro and in vivo. In this chapter, we present recent advances expanding the scope of precursor reactivity and we introduce new biomedical methodology based on bioorthogonal tetrazine chemistry. We specifically highlight novel applications for different kinds of biomolecules, including nucleic acid, protein, antibodies, lipids, glycans, and bioactive small molecules, in the areas of imaging, detection, and diagnostics. We also briefly present other recently developed inverse electron-demand Diels–Alder bioorthogonal reactions. Lastly, we consider future directions and potential roles that inverse electron-demand Diels–Alder reactions may play in the fields of bioorthogonal and biomedical chemistry.
TL;DR: This review focuses on the excited-state dynamics in these intriguing nanomaterials, covering a range of different relaxation mechanisms that span over 15 orders of magnitude, from a few femtoseconds to a few seconds after photoexcitation.
Abstract: Colloidal semiconductor nanocrystals have attracted continuous worldwide interest over the last three decades owing to their remarkable and unique sizeand shape-, dependent properties. The colloidal nature of these nanomaterials allows one to take full advantage of nanoscale effects to tailor their optoelectronic and physical–chemical properties, yielding materials that combine size-, shape-, and composition-dependent properties with easy surface manipulation and solution processing. These features have turned the study of colloidal semiconductor nanocrystals into a dynamic and multidisciplinary research field, with fascinating fundamental challenges and dazzling application prospects. This review focuses on the excited-state dynamics in these intriguing nanomaterials, covering a range of different relaxation mechanisms that span over 15 orders of magnitude, from a few femtoseconds to a few seconds after photoexcitation. In addition to reviewing the state of the art and highlighting the essential concepts in the field, we also discuss the relevance of the different relaxation processes to a number of potential applications, such as photovoltaics and LEDs. The fundamental physical and chemical principles needed to control and understand the properties of colloidal semiconductor nanocrystals are also addressed.
TL;DR: A compact snapshot of the current convergence of novel developments relevant to chemical engineering is given, focusing on the control of cavitation as a means to improve the energy efficiency of sonochemical reactors, as well as in the solids handling with ultrasound.
Abstract: A compact snapshot of the current convergence of novel developments relevant to chemical engineering is given. Process intensification concepts are analysed through the lens of microfluidics and sonochemistry. Economical drivers and their influence on scientific activities are mentioned, including innovation opportunities towards deployment into society. We focus on the control of cavitation as a means to improve the energy efficiency of sonochemical reactors, as well as in the solids handling with ultrasound; both are considered the most difficult hurdles for its adoption in a practical and industrial sense. Particular examples for microfluidic clogging prevention, numbering-up and scaling-up strategies are given. To conclude, an outlook of possible new directions of this active and promising combination of technologies is hinted.
TL;DR: This review presents the fundamental aspects of acoustic cavitation and theoretical aspects behind sonochemistry such as dynamics of bubble oscillation, the rectified diffusion process that is responsible for the growth of Cavitation bubbles, near adiabatic collapse of cavitation bubbles resulting in extreme reaction conditions and several chemical species generated within collapsing bubbles that are responsible for various redox reactions.
Abstract: Sonochemistry refers to ultrasound-initiated chemical processes in liquids. The interaction between bubbles and sound energy in liquids results in acoustic cavitation. This review presents the fundamental aspects of acoustic cavitation and theoretical aspects behind sonochemistry such as dynamics of bubble oscillation, the rectified diffusion process that is responsible for the growth of cavitation bubbles, near adiabatic collapse of cavitation bubbles resulting in extreme reaction conditions and several chemical species generated within collapsing bubbles that are responsible for various redox reactions. Specifically, a detailed discussion on single bubble sonochemistry is provided.
TL;DR: The robustness of inert phenol derivatives under typically used catalytic conditions as well as their utility as a directing group allow unique synthetic applications of these new C–O cross-coupling reactions, which is also included in cases where appropriate.
Abstract: Nickel-catalyzed cross-coupling reactions of aryl esters, carbamates, carbonates, ethers and arenols are reviewed. Carbon–oxygen bonds in these phenol derivatives cannot be activated by palladium, a typical cross-coupling catalyst, but a low valent nickel species in conjunction with a strong r-donor ligand is uniquely effective for achieving this. The review is organized primarily by substrate class and secondarily by coupling partners, encompassing organometallics, heteroatom nucleophiles, C–H bonds and many others. Although the reactions in this category are covered thoroughly, each reaction is described only briefly, so that it is possible to quickly overview the spectrum of nickel-catalyzed cross-coupling reactions of inert phenol derivatives. The robustness of inert phenol derivatives under typically used catalytic conditions as well as their utility as a directing group allow unique synthetic applications of these new C–O cross-coupling reactions, which is also included in cases where appropriate. Mechanistic aspects of C–O bond activation by nickel are also summarized, highlighting their diversity compared with the C–X bond activation involved in conventional cross-coupling processes.
TL;DR: Progress in nickel-catalyzed cross-coupling reaction of alkyl electrophiles with sp3-, sp2-, and sp-hybridized organometallic reagents including asymmetric variants as well as mechanistic insights of nickel catalysis are reviewed in this chapter.
Abstract: Much effort has been devoted to developing new methods using Ni catalysts for the cross-coupling reaction of alkyl electrophiles with organometallic reagents, and significant achievements in this area have emerged during the past two decades. Nickel catalysts have enabled the coupling reaction of not only primary alkyl electrophiles, but also sterically hindered secondary and tertiary alkyl electrophiles possessing β-hydrogens with various organometallic reagents to construct carbon skeletons. In addition, Ni catalysts opened a new era of asymmetric cross-coupling reaction using alkyl halides. Recent progress in nickel-catalyzed cross-coupling reaction of alkyl electrophiles with sp(3)-, sp(2)-, and sp-hybridized organometallic reagents including asymmetric variants as well as mechanistic insights of nickel catalysis are reviewed in this chapter.
TL;DR: This review attempts to provide a comprehensive understanding of the evolution of cross-dehydrogenative coupling via iron catalysis, as well as its application in synthetic chemistry.
Abstract: Cross-dehydrogenative coupling (CDC), which enables the formation of carbon–carbon (C–C) and C–heteroatom bonds from the direct coupling of two C–H bonds or C–H/X–H bonds, represents a new state of the art in the field of organic chemistry. Iron, a prominent metal, has already shown its versatile application in chemical synthesis. This review attempts to provide a comprehensive understanding of the evolution of cross-dehydrogenative coupling via iron catalysis, as well as its application in synthetic chemistry.
TL;DR: This methodology has shown preeminent power to construct 5-, 6-, or 7-membered heterocyclic as well as carbon rings.
Abstract: The cascade [1,n]-hydrogen transfer/cyclization, recognized as the tert-amino effect one century ago, has received considerable interest in recent decades, and great achievements have been made. With the aid of this strategy, the inert C(sp3)–H bonds can be directly functionalized into C–C, C–N, C–O bonds under catalysis of Lewis acids, Bronsted acids, as well as organocatalysts, and even merely under thermal conditions. Hydrogen can be transferred intramolecularly from hydrogen donor to acceptor in the form of hydride, or proton, followed by cyclization to furnish the cyclic products in processes featuring high atom economy. Methylene/methine adjacent to heteroatoms, e.g., nitrogen, oxygen, sulfur, can be exploited as hydride donor as well as methylene/methine without heteroatom assistance. Miscellaneous electrophilic subunits or intermediates, e.g., alkylidene malonate, carbophilic metal activated alkyne or allene, α,β-unsaturated aldehydes/ketone, saturated aldehydes/iminium, ketenimine/carbodiimide, metal carbenoid, electron-withdrawing groups activated allene/alkyne, in situ generated carbocation, can serve as hydride acceptors. This methodology has shown preeminent power to construct 5-, 6-, or 7-membered heterocyclic as well as carbon rings. In this chapter, various hydrogen donors and acceptors are adequately discussed.
TL;DR: This review describes recent progress in nickel-catalyzed aromatic C–H functionalization reactions classified by reaction types and reaction partners and cutting-edge syntheses of natural products and pharmaceuticals using nickel- Catalytic C–h functionalization are presented.
Abstract: Catalytic C-H functionalization using transition metals has received significant interest from organic chemists because it provides a new strategy to construct carbon-carbon bonds and carbon-heteroatom bonds in highly functionalized, complex molecules without pre-functionalization. Recently, inexpensive catalysts based on transition metals such as copper, iron, cobalt, and nickel have seen more use in the laboratory. This review describes recent progress in nickel-catalyzed aromatic C-H functionalization reactions classified by reaction types and reaction partners. Furthermore, some reaction mechanisms are described and cutting-edge syntheses of natural products and pharmaceuticals using nickel-catalyzed aromatic C-H functionalization are presented.
TL;DR: This review article aims to describe the main achievements on the direct carboxylation of unsaturated hydrocarbons with CO2 by using cheap and available Ni or Fe catalytic species.
Abstract: The sustainable utilization of available feedstock materials for preparing valuable compounds holds great promise to revolutionize approaches in organic synthesis. In this regard, the implementation of abundant and inexpensive carbon dioxide (CO2) as a C1 building block has recently attracted considerable attention. Among the different alternatives in CO2 fixation, the preparation of carboxylic acids, relevant motifs in pharmaceuticals and agrochemicals, is particularly appealing, thus providing a rapid and unconventional entry to building blocks that are typically prepared via waste-producing protocols. While significant advances have been realized, the utilization of simple unsaturated hydrocarbons as coupling partners in carboxylation events is undoubtedly of utmost academic and industrial relevance, as two available feedstock materials can be combined in a catalytic fashion. This review article aims to describe the main achievements on the direct carboxylation of unsaturated hydrocarbons with CO2 by using cheap and available Ni or Fe catalytic species.
TL;DR: In this chapter, a general outline of the features of such processes is detailed and the development of photoredox/Ni dual catalytic methods for cross-coupling has opened new vistas for the construction of carbon–carbon bonds at C(sp3)-hybridized centers.
Abstract: The traditional transition metal-catalyzed cross-coupling reaction, although well suited for C(sp2)–C(sp2) cross-coupling, has proven less amenable toward coupling of C(sp3)-hybridized centers, particularly using functional group tolerant reagents and reaction conditions. The development of photoredox/Ni dual catalytic methods for cross-coupling has opened new vistas for the construction of carbon–carbon bonds at C(sp3)-hybridized centers. In this chapter, a general outline of the features of such processes is detailed.
TL;DR: This overview suggests that further progress can be achieved in the near future, with enhanced availability of more robust, stronger, and cheaper NIR luminophores, and on the design strategies that may increase the luminescence efficiency, while pushing the emission band more deeply in the NIR region.
Abstract: In recent years, the interest in near-infrared (NIR) emitting molecules and materials has increased significantly, thanks to the expansion of the potential technological applications of NIR luminescence in several areas such as bioimaging, sensors, telecommunications, and night-vision displays. This progress has been facilitated by the development of new synthetic routes for the targeted functionalization and expansion of established molecular frameworks and by the availability of simpler and cheaper NIR detectors. Herein, we present recent developments on three major classes of systems—i.e., organic dyes, porphyrinoids, and transition metal complexes—exhibiting the maximum of the emission band at λ > 700 nm. In particular, we focus on the design strategies that may increase the luminescence efficiency, while pushing the emission band more deeply in the NIR region. This overview suggests that further progress can be achieved in the near future, with enhanced availability of more robust, stronger, and cheaper NIR luminophores.
TL;DR: An overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects is provided.
Abstract: Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects. The latest progresses in advancing analytical approaches, characterising materials and understanding their degradation, and developing methods for monitoring their stability are discussed. Case studies from the literature are presented to examine how the choice of the working conditions and the analytical approaches is driven by the analytical and technical question to be answered, as well as the nature of the object from which the samples are collected.
TL;DR: This section covers both metal–organic and organic materials that feature thermally activated delayed fluorescence (TADF) and compares both material classes to show commonalities and differences, highlighting current issues and challenges.
Abstract: This section covers both metal-organic and organic materials that feature thermally activated delayed fluorescence (TADF). Such materials are especially useful for organic light-emitting diodes (OLEDs), a technology that was introduced in commercial displays only recently. We compare both material classes to show commonalities and differences, highlighting current issues and challenges. Advanced spectroscopic techniques as valuable tools to develop solutions to those issues are introduced. Finally, we provide an outlook over the field and highlight future trends.
TL;DR: The surface hopping approach, the methods for computation of excited states based on DFT, the connection between these methodologies, and their diverse implementations are reviewed and the shortcomings of the methods are critically addressed.
Abstract: Nonadiabatic dynamics simulation of electronically-excited states has been a research area of fundamental importance, providing support for spectroscopy, explaining photoinduced processes, and predicting new phenomena in a variety of specialties, from basic physical-chemistry, through molecular biology, to materials engineering. The demands in the field, however, are quickly growing, and the development of surface hopping based on density functional theory (SH/DFT) has been a major advance in the field. In this contribution, the surface hopping approach, the methods for computation of excited states based on DFT, the connection between these methodologies, and their diverse implementations are reviewed. The shortcomings of the methods are critically addressed and a number of case studies from diverse fields are surveyed.
TL;DR: An overview of the current state-of-the-art of gold-based nanomaterials (Au NPs) in medical applications is given, and the preparation methods for various Au NPs including functionalization strategies for selective targeting are summarized.
Abstract: In this review, an overview of the current state-of-the-art of gold-based nanomaterials (Au NPs) in medical applications is given. The unique properties of Au NPs, such as their tunable size, shape, and surface characteristics, optical properties, biocompatibility, low cytotoxicity, high stability, and multifunctionality potential, among others, make them highly attractive in many aspects of medicine. First, the preparation methods for various Au NPs including functionalization strategies for selective targeting are summarized. Second, recent progresses on their applications, ranging from the diagnostics to therapeutics are highlighted. Finally, the rapidly growing and promising field of gold-based theranostic nano-platforms is discussed. Considering the great body of existing information and the high speed of its renewal, we chose in this review to generalize the data that have been accumulated during the past few years for the most promising directions in the use of Au NPs in current medical research.
TL;DR: This chapter describes the use of ultrasound in remediation of wastewater contaminated with organic pollutants in the absence and presence of other advanced oxidation processes (AOPs) such as sonolysis, sono-ozone process, sonophotocatalysis, sonsoFenton systems and sonophoto-Fenton methods in detail.
Abstract: This chapter describes the use of ultrasound in remediation of wastewater contaminated with organic pollutants in the absence and presence of other advanced oxidation processes (AOPs) such as sonolysis, sono-ozone process, sonophotocatalysis, sonoFenton systems and sonophoto-Fenton methods in detail. All these methods are explained with the suitable literature illustrations. In most of the cases, hybrid AOPs (combination of ultrasound with one or more AOPs) resulted in superior efficacy to that of individual AOP. The advantageous effects such as additive and synergistic effects obtained by operating the hybrid AOPs are highlighted with appropriate examples. It is worth to mention here that the utilization of ultrasound is not only restricted in preparation of modern active catalysts but also extensively used for the wastewater treatment. Interestingly, ultrasound coupled AOPs are operationally simple, efficient, and environmentally benign, and can be readily applied for large scale industrial processes which make them economically viable.
TL;DR: Several non-invasive methods by portable equipment, including XRF, mid- and near-FTIR, UV–Vis and Raman spectroscopy, as well as XRD, are discussed in detail along with their impact on the understanding of painting materials and execution techniques.
Abstract: The in situ non invasive methods have experienced a significant development in the last decade because they meet specific needs of analytical chemistry in the field of cultural heritage where artworks are rarely moved from their locations, sampling is rarely permitted, and analytes are a wide range of inorganic, organic and organometallic substances in complex and precious matrices. MOLAB, a unique collection of integrated mobile instruments, has greatly contributed to demonstrate that it is now possible to obtain satisfactory results in the study of a variety of heritage objects without sampling or moving them to a laboratory. The current chapter describes an account of these results with particular attention to ancient, modern, and contemporary paintings. Several non-invasive methods by portable equipment, including XRF, mid- and near-FTIR, UV–Vis and Raman spectroscopy, as well as XRD, are discussed in detail along with their impact on our understanding of painting materials and execution techniques. Examples of successful applications are given, both for point analyses and hyperspectral imaging approaches. Lines for future perspectives are finally drawn.