Enzymes are most efficient catalyst for organic transformations including halogenation of C–H bonds. Most of the halogenating enzymes utilize high valent metal-oxo intermediates for hydrogen atom abstraction (HAA) and subsequent haloalkane formation. Due to high demand of organohalide compounds, many attempts have been made to mimic the active sites of halogenating enzymes in order to achieve efficacy of enzymes. Different first row transition metals complexes have been synthesized using various ligand systems. In this review, we have summarized the efforts made towards development of halogenation using high valent metal-oxo complexes and understanding the mechanism of their activity.

Imido complexes of early transition metals are key intermediates in the synthesis of many nitrogen-containing organic compounds. The metal—nitrogen double bond of the imido moiety undergoes [2+2] cycloaddition reactions with various unsaturated organic molecules to form new nitrogen—carbon and nitrogen—heteroatom bonds. This review article focuses on reactivity of the terminal imido complexes of Group 4–6 metals, summarizing their stoichiometric reactions and catalytic applications for a variety of reactions including alkyne hydroamination, alkyne carboamination, pyrrole formation, imine metathesis, and condensation reactions of carbonyl compounds with isocyanates.

Gold compounds have emerged as a novel class of metallodrugs with a promising future in medicinal inorganic chemistry. Despite gold compounds have been intensively investigated for the treatment of many diseases, their mechanism of action is not fully understood at the molecular level. However, the recognition process by proteins is accepted as a key feature for the biological activity of these molecules. This review presents the research performed during the last decade(s) concerning the structural studies on the products of the reactions between gold-based drugs and proteins. A comparative analysis of the structural features of the known gold/protein adducts suggests that several binding mechanisms are possible. It emerges that gold(III) compounds break down before or upon protein binding and that Au(III) reduces to Au(I) during this process. In agreement with the hard and soft acids and bases (HSAB) theory, Au(I) centers prefer thiolates of free Cys side chains; sulfur atoms of Met are less frequently observed, while N atoms of the side chains of His, Lys, Arg and Gln and O atoms of Glu and Asp are also possible Au binding sites. Au can bridge two protein residue side chains (Cys/Cys, Cys/His, Cys/Asp, Cys/Asn, His/His, His/Lys, His/Gln); Au…π interactions can also be formed. The formation of gold/protein adducts does not alter the overall folding of the investigated proteins, but it can modify the active site conformation, inhibiting the enzymatic activity. The process of gold metalation of proteins is selective.

The most widely studied spin crossover (SCO) systems are those involving hexacoordinate iron(II) complexes immerse in the “magic” N6 coordination sphere. In this review the properties of SCO-active metal complexes containing unusual metal centres and/or coordination spheres are analysed, except for Fe3+ complexes that have been recently reviewed. The SCO-properties of the less studied SCO metal centres Cr2+, Mn2+, Mn3+ and Co2+ are presented, showing great advances in the development of bistable materials containing first row transition metals other than Fe. Finally, an analysis of the changes in the structural parameters, bond lengths and angles, during the spin conversion is presented for those complexes structurally characterised by X-ray crystallography in both high- and low-spin states.

Recently, synthetic efforts to prepare novel modified porphyrinoid skeletons have been an important area of research due to its promising applications in various fields ranging from material chemistry to life science. The formation of [14]triphyrin(2.1.1) as relatively new congeners among the porphyrinoids seems quite astonishing because porphyrin macrocyclic core itself is perturbed to afford a contracted structure retaining aromaticity, however, exhibiting fundamentally different properties compared to other members in the porphyrin family. Although [14]triphyrin(2.1.1) chemistry has been mentioned in the literature, an effort which exclusively focussed on the development of [14]triphyrin(2.1.1) was not made. In the current review, we focused on the recent advancement in the chemistry of [14]triphyrin(2.1.1) including its synthesis, structure, coordination chemistry, photophysical and electrochemical properties. A fundamental insight in the triphyrin chemistry has immense scope since the reactivity of the molecule is less explored other than using as a ligand to prepare a few metal complexes and coupling reactions. The present review will definitely add to the furtherance of the chemistry of [14]triphyrin(2.1.1).

The electrocatalytic water splitting is considered as a prospect meaning to address the urgent energy and environmental problems. However, the electrocatalytic water splitting is greatly limited by the high overpotentials of hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Especially, OER involves a complex multistep proton-coupled electron transfer process, which demands a high overpotential to accelerate this sluggish oxygen evolution kinetics. The high overpotentials for OER significantly decrease the efficiency of the overall water splitting. The OER half reaction has thus become the bottleneck of electrocatalytic overall water splitting. It is vital to synthesize highly active electrocatalysts to reduce the activation energy of the reaction and accelerate the generation of H2 and O2, thereby improving the efficiency of the overall water splitting. Prussian blue analogues (PBAs) are representative cyanide-based coordination polymer materials. PBAs possess open framework structures, large specific surface areas, adjustable metal active sites and uniform catalytic centers, showing promising application in electrocatalytic water splitting. Besides, benefiting from the unique structural features of PBAs, their derived electrocatalysts also have large specific surface areas and uniform active sites. Moreover, PBAs can serve as carbon and nitrogen sources. The doped N can regulate the electronic structure of surface active sites, enhancing the intrinsic activity of electrocatalysts. Therefore, the PBA-derived electrocatalysts also exhibit good catalytic performance for water splitting. In this review, we not only summarize the most recent advances on PBAs and their derivatives as electrocatalysts for water splitting, but also conclude the core scientific challenges faced in water splitting. Finally, we provide perspectives for the future research in this field, including catalyst design, catalytic system establishment and so on.

The electrochemical analysis of molecular catalysts for the conversion of bulk feedstocks into energy-rich clean fuels has seen dramatic advances in the last decade. More recently, increased attention has focused on the characterization of metal-organic frameworks (MOFs) containing well-defined redox and catalytically active sites, with the overall goal to develop structurally stable materials that are industrially relevant for large-scale solar fuel syntheses. Successful electrochemical analysis of such materials draws heavily on well-established homogeneous techniques, yet the nature of solid materials presents additional challenges. In this tutorial-style review, we cover the basics of electrochemical analysis of electroactive MOFs, including considerations of bulk stability, methods of attaching MOFs to electrodes, interpreting fundamental electrochemical data, and finally electrocatalytic kinetic characterization. We conclude with a perspective of some of the prospects and challenges in the field of electrocatalytic MOFs.

As a typical green methodology, enzymatic catalysis has been extensively employed in multitudinous chemical and biological transformation procedures. However, intrinsic fragile nature of enzymes makes them prone to denaturation or destabilization in harsh practical conditions, leading to unavoidably shortened lifespan and extremely high cost. It was proven that enzyme immobilization is an efficient strategy for enhancing their catalytic performance in continuous industrial practices. Metal-Organic Frameworks (MOFs) with extremely high specific surface area, abundant porosity, extraordinary multifunctionality, and relatively high stability, in recent years, have attracted remarkable research interests as novel supporting matrices for efficient enzyme immobilization and protection. Many reported MOFs-enzyme composites exhibit unprecedented catalytic performances than those of free enzymes, including improved enzyme efficiency, stability, selectivity, and recyclability, due to the protection of enzymes by highly ordered frameworks. To present a systematic overview of this emerging and developing field, herein, we summarize an update review about the most recent advances in MOFs immobilizing enzymes from the aspects of general synthetic approaches, critical impact factors, enhanced catalytic performances, and the practical applications. Subsequently, the emerging theories, methodologies and technologies in this thriving area are briefly introduced. Finally, barriers and future perspectives about MOFs for enzyme immobilization are also discussed.

Boron neutron capture therapy (BNCT) is a potential cancer radiotherapeutic modality, which takes advantage of the neutron capture response that occurs when boron (10B) is struck by low-energy thermal neutrons, triggering a nuclear fission reaction that ultimately causes cell death. Because the fatal radiation is restricted to approximately a single cell diameter, only cells with significant boron accumulation that are in the neutron field will be destroyed. Tumor-targeted 10B delivery agents are an essential component of BNCT. Currently, two low molecular weight boron-containing compounds, sodium mercaptoundecahydro-closo-dodecaborate (BSH) and borylphenylalanine (BPA), are mainly used in BNCT. Although both have suboptimal tumor selectivity, they have shown some therapeutic effect in patients with high-grade gliomas and several other kinds of tumors. In order to improve the efficacy of BNCT, significant effort has been devoted to developing new boron delivery agents that possess better uptake and favorable pharmacokinetic characteristics for clinical use. This review focuses on various boron delivery agents that have been developed over the past 40 years, including boron-containing amino acids, boron-containing compound conjugated-nucleosides, porphyrin derivatives, peptides, monoclonal antibodies, and different types of nanomaterials for 10B delivery. The principles underlying BNCT and the clinical trials with BNCT are briefly introduced in the first part of this review. In the second part, we provide a detailed overview of various boron delivery agents and discuss their merits and limitations. Additionally, the preclinical outcomes of these agents are included in this review and the most promising delivery agents are highlighted and compared. In summary, this article provides an overview of boron delivery agents, and critically analyzes their clinical prospects, from the view of medicinal chemists and nuclear medicine physicians.

Ligand noninnocence has been well-established for transition metal complexes containing diatomics such as NO and O2, and bidentate chelates like quinones/semiquinones/catecholates, α-diimines, and α-dithiolenes and also tetrapyrrole macrocycles. The scope of noninnocent ligands is being expanded rapidly for their unique redox properties and catalytic applications. The present contribution attempts to reveal “hidden” noninnocence of molecules that are often believed to be innocent, which includes 1,3-butadiene dianion, carbodicarbene and peroxo ligand, as well as reductive noninnocence of porphyrins and corroles.

Metal-organic frameworks (MOFs) are an important class of inorganic-organic hybrid crystals with applications in various fields. In last ten years, MOFs-based fluorescence sensing has gained much attention. MOFs can exhibit luminescence by metal nodes, ligands and the inserted or absorbed guests, which offer an excellent fluorescence response in analyzing. However, MOFs-based monochromatic fluorescence probes are limited by concentration, the effect of ambient and excitation light intensity, resulting in low detection accuracy. To overcome this defect, MOFs-based ratiometric fluorescence (RF) sensors have been proposed and rapidly developed. This review focuses on the design tactics of MOFs-based RF sensing and describes the detection mechanism of different RF sensors. Based on different strategies of synthesis, the MOFs-based RF sensors are categorized into three classes: MOFs’ intrinsic dual-emission, single-emissive MOFs with a chromophore and non-emissive MOFs with two chromophores. In each categorization, the design approaches and relative merits were discussed separately. Finally, the applications of MOFs-based RF sensors are summarized and prospected.

The potential of environmentally and technically relevant NO2 for non-innocent ligand behavior in coordination compounds is being evaluated in comparison with the well-studied metal complexes of nitrosyl, NOn (n = +,0,-,2-). A ruthenium semiquinone (Q−) radical complex platform [Ru(Q)(L)(NOx)] (x = 1 or 2, L = mer tridentate ligand) can serve to contrast the ligand characteristics of (NO)n and (NO2)n. Strategies to stabilize metal coordinated nitrogen dioxide (as “nitro” ligand NO2) versus the well established nitrite NO2− are suggested.

Extensive attention has been paid to develop effective systems for the detection of formaldehyde, carbon monoxide and phosgene due to their extreme toxicity and ready accessibility. Numerous methods have been developed for the design and detection of these substances nowadays, such as electro-fluorescent biosensors, piezoelectric sensors, semiconductor sensors, colorimetric probes, quartz crystal microbalance, Raman spectroscopy, transmission electro-microscopy (TEM), gas chromatography, liquid chromatography and X-ray diffraction (XRD), but fluorescent probes, which rely on chemical reactions between the probes and the target, provoking a dramatic fluorescence change, often remain the most commonly employed method for detecting such important small molecules. This review will cover the most significant developments in fluorescent probes for the detection of the carbonyl species formaldehyde, carbon monoxide and phosgene in recent years (typically the last 10 years), with a special emphasis on their mechanisms and applications.

Following the systematic nomenclature recommended by the IUPAC for other π,σ-hole interactions, a nobel gas (or aerogen) bond (NgB) is defined as the attractive interaction between an electron rich atom or group of atoms and any element of Group-18 acting as electron acceptor. Investigations on π,σ-hole interactions and their applications in crystal engineering, molecular recognition and catalysis have exponentially grown in recent years. For obvious reasons, investigations on noncovalent Ng bonding interactions are less abundant compared to their sisters (halogen, chalcogen, pnictogen and tetrel bonding, namely XB, ChB, PnB and TrB, respectively). In this review, we put into perspective the available theoretical and experimental investigations on σ-hole and π-hole interactions involving noble gas atoms. We describe a number of theoretical works revealing that NgB follows the typical behavior already described for XB, ChB, PnB and TrB, where stronger interactions occur moving the whole group down. A search the Cambridge Structural Database (CSD) and Inorganic Crystal Structure Database (ICSD) reveals that there are several X-ray structures of xenon derivatives where NgB interaction is crucial for the crystal packing stability. This taking is sub-divided into three sections subject to the oxidation state of xenon. The crystallographic search evidences that interactions between Xe and electron rich atoms are frequent and directional.

To exploit the use of solar energy in photocatalysis, metal ion doping is one of the most effective ways. At present, atomically precise heterometallic polyoxotitanium clusters (HPTCs) are of great interest as well-defined models for the way in which metal ions are doped into bulk titanium dioxide. Recently, researchers have contributed great efforts in HPTCs where majority metal ions throughout the periodic table have successfully incorporated. The incorporation of particular characteristics of metal dopants provides the opportunity to modify the microscopic electronic structure, then optical response, and ultimate macroscopical performances. In this review, we aim to summarize the recent progress on such a rapidly evolving topic of HPTCs and provide potential theoretical models for the rational design of photocatalysts and solar energy capture. Firstly, a brief summary of the synthetic strategies and bonding models between the metals and PTCs is provided. Then clear definition and classification of the HPTCs reported up to date is given. Moreover, representative examples are illustrated from experimental, theoretical and photophysical/photochemical perspectives, particularly in light absorption, fluorescence, photocatalysis, and gas sorption etc. Finally, the main challenges and opportunities are proposed with the goal of expanding the sunlight harvesting application range of HPTCs.

Research in the field of M⋯H–X interactions has found application in X–H bond activation, crystal engineering and the construction of supramolecular structures, fast ligand exchange phenomena in solution and biological chemistry. The wealth of literature available on inter- and intramolecular M⋯H–B (M = CuI, AgI) associations allow their grouping and subclassification based on inner sphere complex coordination. An insufficient number of M⋯H–X (X = N, O, Si) interactions, suitably metrically characterized for the purpose of critical comparison, is known. The few well-studied examples of M⋯H–C (M = CuI/II, AgI) interactions exhibit certain close analogies with, but also largely diverging binding situations from, the B–H benchmarks. Attachment of highly polarized ZnIIH or AlIIIH units to CuI complex fragments adds a new dimension to the M⋯H–X intermolecular interaction phenomenon, taking it into unexplored territory.

Recently, substantial efforts had been made in the field of synthetic iron compounds as structural and functional models of the hydrogenase enzyme active site for the purpose of developing potential catalysts for effective and inexpensive hydrogen evolution. Amongst the bioinspired mimics, the iron carbonyl compounds bearing aromatic dithiolate bridged ligands featured the robust and tunable reductions at relatively positive potentials, and provided an appealing scaffold for easily molecular engineering, modular variation, functionalized incorporation/encapsulation of the mimetic compounds. This article surveyed and discussed a wide variety of mono-, di-, poly-nuclear iron carbonyl compounds with aromatic dithiolate bridges as synthetic “artificial” mimics of the catalytic site of [FeFe] hydrogenase in terms of structures, syntheses, redox properties, electrocatalytic characteristics in organic and aqueous solutions, and photocatalytic hydrogen evolutions. We hope that the descriptions and discussions in present review will shed light on some helpful aspects for further development of new generations of artificial catalysts for a future hydrogen economy.

Despite its natural abundance and widespread use as food, paint additive, and in bone implants, no specific biological function of titanium is known in the human body. High concentrations of Ti(IV) could result in cellular toxicity, however, the absence of Ti toxicity in the blood of patients with titanium bone implants indicates the presence of one or more biological mechanisms to mitigate toxicity. Similar to Fe(III), Ti(IV) in blood binds to the iron transport protein serum transferrin (sTf), which gives credence to the possibility of its cellular uptake mechanism by transferrin-directed endocytosis. However, once inside the cell, how sTf bound Ti(IV) is released into the cytoplasm, utilized, or stored remain largely unknown. To explain the molecular mechanisms involved in Ti use in cells we have drawn parallels with those for Fe(III). Based on its chemical similarities with Fe(III), we compare the biological coordination chemistry of Fe(III) and Ti(IV) and hypothesize that Ti(IV) can bind to similar intracellular biomolecules. The comparable ligand affinity profiles suggest that at high Ti(IV) concentrations, Ti(IV) could compete with Fe(III) to bind to biomolecules and would inhibit Fe bioavailability. At the typical Ti concentrations in the body, Ti might exist as a labile pool of Ti(IV) in cells, similar to Fe. Ti could exhibit different types of properties that would determine its cellular functions. We predict some of these functions to mimic those of Fe in the cell and others to be specific to Ti. Bone and cellular speciation and localization studies hint toward various intracellular targets of Ti like phosphoproteins, DNA, ribonucleotide reductase, and ferritin. However, to decipher the exact mechanisms of how Ti might mediate these roles, development of innovative and more sensitive methods are required to track this difficult to trace metal in vivo.

As an NNN-tridentate ligand, the 2,2':6',2"-terpyridine plays an important role in coordination chemistry. With three coordination sites and low LUMO, terpyridine and its derivatives are one of the typical Pincer ligand and/or non-innocent ligands in transition metal catalysis. Interesting catalytic reactivities have been obtained with these tpy-metal complexes targeting some challenging transformations, such as C-C bond formation and hydrofunctionalization. On the other hand, terpyridine ligands can form "closed-shell" octahedral complexes, which provide a linear and stable linkage in supramolecular chemistry. Numerous supramolecular architectures have been achieved using modified terpyridine ligands including Sierpiński triangles, hexagonal gasket and supramolecular rosettes. This review presents a summary of recent progress regarding transition metal-terpyridine complexes with the focus on their applications in catalysis and supramolecular structure construction. Facile synthesis of terpyridine derivatives is also described. We hope this article can serve to provide some general perspectives of the terpyridine ligand and their applications in coordination chemistry.

Several diseases share misfolding of different peptides and proteins as a key feature for their development. This is the case of important neurodegenerative diseases such as Alzheimer's and Parkinson's diseases and type II diabetes mellitus. Even more, metal ions such as copper and zinc might play an important role upon interaction with amyloidogenic peptides and proteins, which could impact their aggregation and toxicity abilities. In this review, the different coordination modes proposed for copper and zinc with amyloid-β, α-synuclein and IAPP will be reviewed as well as their impact on the aggregation, and ROS production in the case of copper. In addition, a special focus will be given to the mutations that affect metal binding and lead to familial cases of the diseases. Different modifications of the peptides that have been observed in vivo and could be relevant for the coordination of metal ions are also described.

The purpose of this review is to provide an overview of uranium speciation using vibrational spectroscopy methods including Raman and IR. Uranium is a naturally occurring, radioactive element that is utilized in the nuclear energy and national security sectors. Fundamental uranium chemistry is also an active area of investigation due to ongoing questions regarding the participation of 5f orbitals in bonding, variation in oxidation states and coordination environments, and unique chemical and physical properties. Importantly, uranium speciation affects fate and transportation in the environment, influences bioavailability and toxicity to human health, controls separation processes for nuclear waste, and impacts isotopic partitioning and geochronological dating. This review article provides a thorough discussion of the vibrational modes for U(IV), U(V), and U(VI) and applications of infrared absorption and Raman scattering spectroscopies in the identification and detection of both naturally occurring and synthetic uranium species in solid and solution states. The vibrational frequencies of the uranyl moiety, including both symmetric and asymmetric stretches are sensitive to the coordinating ligands and used to identify individual species in water, organic solvents, and ionic liquids or on the surface of materials. Additionally, vibrational spectroscopy allows for the in situ detection and real-time monitoring of chemical reactions involving uranium. Finally, techniques to enhance uranium species signals with vibrational modes are discussed to expand the application of vibrational spectroscopy to biological, environmental, inorganic, and materials scientists and engineers.

Synthetic pyrrole-based anion receptors date back to the 1990s. They have been extensively developed in the context of macrocyclic systems as expanded porphyrins and calixpyrroles, and related systems. The chemistry of open-chain pyrrolic systems is, in many respects, no less venerable. It also has more direct analogy to naturally occurring pyrrole-based anion binding motifs. However, it has not been the subject of a comprehensive review. Presented herein is a summary of efforts devoted to the creation of de novo pyrrole-based receptors, as well as the anion recognition chemistry of naturally occurring pyrrolic systems as prodigiosins and their synthetic analogues.

Continual advancements in the development of synchrotron radiation sources have resulted in X-ray based spectroscopic techniques capable of probing the electronic and structural properties of numerous systems. This review gives an overview of the application of metal K-edge and L-edge X-ray absorption spectroscopy (XAS), as well as K resonant inelastic X-ray scattering (RIXS), to the study of electronic structure in transition metal sites with emphasis on experimentally quantifying 3d orbital covalency. The specific sensitivities of K-edge XAS, L-edge XAS, and RIXS are discussed emphasizing the complementary nature of the methods. L-edge XAS and RIXS are sensitive to mixing between 3d orbitals and ligand valence orbitals, and to the differential orbital covalency (DOC), that is, the difference in the covalencies for different symmetry sets of the d orbitals. Both L-edge XAS and RIXS are highly sensitive to and enable separation of and donor bonding and back bonding contributions to bonding. Applying ligand field multiplet simulations, including charge transfer via valence bond configuration interactions, DOC can be obtained for direct comparison with density functional theory calculations and to understand chemical trends. The application of RIXS as a probe of frontier molecular orbitals in a heme enzyme demonstrates the potential of this method for the study of metal sites in highly covalent coordination sites in bioinorganic chemistry.

The surfaces of colloidal nanocrystals are complex interfaces between solid crystals, coordinating ligands, and liquid solutions. For fluorescent quantum dots, the properties of the surface vastly influence the efficiency of light emission, stability, and physical interactions, and thus determine their sensitivity and specificity when they are used to detect and image biological molecules. But after more than 30 years of study, the surfaces of quantum dots remain poorly understood and continue to be an important subject of both experimental and theoretical research. In this article, we review the physics and chemistry of quantum dot surfaces and describe approaches to engineer optimal fluorescent probes for applications in biomolecular imaging and sensing. We describe the structure and electronic properties of crystalline facets, the chemistry of ligand coordination, and the impact of ligands on optical properties. We further describe recent advances in compact coatings that have significantly improved their properties by providing small hydrodynamic size, high stability and fluorescence efficiency, and minimal nonspecific interactions with cells and biological molecules. While major progress has been made in both basic and applied research, many questions remain in the chemistry and physics of quantum dot surfaces that have hindered key breakthroughs to fully optimize their properties.

Although the high efficiency of the homogeneous processes, using rhodium or iridium complexes, was clearly demonstrated industrially, heterogeneous catalysts offer the advantages of facile product separation and vapor phase operation, which often limit catalyst losses. Both noble and non-noble metal homogeneous and heterogeneous catalyzed carbonylation of methanol have been studied for many years. In this short chapter, we intend to analyze the recent evolutions of the most promising catalytic systems for this important reaction of catalysis. A presentation by metals was chosen, always referring to the origins of the first catalytic systems.

This review describes the recent advances in ruthenium–nitrosoarene chemistry. The preparations of Ru–nitrosoarene complexes by (1) intermolecular nitrosonium insertion into Ru–aryl bonds, and (2) Ru-induced symmetric or asymmetric cleavage of benzofuroxan, are discussed. The exploration of the redox non-innocence of the coordinated nitrosoarene, dinitrosoarene and structurally related ligands via structural, spectroscopic, electrochemical and computational studies are presented.

Proton reduction is a critical reaction for the efficient utilization of solar fuels and the development of a hydrogen economy. Molecular proton reduction catalysts help us to understand how hydrogenases function in nature, on one hand, and inspire us to design new practical materials on the other. This manuscript introduces the concept of electrocatalytic and photocatalytic proton (hydrogen evolution) in a homogeneous system, and then reviews recent studies on molecular proton reduction catalysts that contain 3d transition metal centers (Mn, Fe, Co, and Ni) surrounded by polypyridine ligands. The discussion focuses on the design, structure, and catalytic behavior of these metal polypyridine catalysts. Catalytic pathways, and how they are affected by complex structure, are addressed in order to offer rational suggestions for the future preparation of promising hydrogen evolution catalysts.

Multinuclear metal complexes have shown a unique capacity to provide interesting magnetic, chemical and electronic properties by virtue of the remarkably diverse range of structural types that they exhibit. Calix[n]arenes are now a mature synthetic platfom that provide for a diverse spatial arrangement of binding groups, making them highly suitable to use for the formation of multinuclear metal ion complexes. Increasing interest has been shown in the development and properties of magnetic materials based on calixarene macrocycles. Here, we review the magnetic properties of calixarene-supported metal clusters with emphasis on those examples exhibiting slow magnetic relaxation.

Metal-Organic Frameworks (MOFs) are hybrid organic-inorganic materials with enhanced electronic and optical functionalities that can be tailored by the judicious selection of the building units or their combinations. A large-scale diversity of metal-ligand combinations, along with the ability to form composites, have allowed MOFs to realize enhanced luminescence functionality with applicability in the avenues of solid-state lighting, luminescence-based sensors, and organic light emitting diodes (OLEDs). Because of their enhanced fluorescence lifetimes, high quantum efficiencies, and large-scale tunability, the luminescent MOFs and their composites hold great promise for the OLED industry with enhanced potential to resolve low efficiency issues. The present article presents a comprehensive review of emerging applications for luminescent MOFs and their composites in various OLED applications, with a focus on key attributes like quantum efficiencies, emission lifetimes, tunability, Commission internationale de l'éclairage (CIE) color coordinates, etc. At last, the prospects of luminescent MOFs have been addressed with respect to their future roles and applications in the OLED industry.

Apart from a short introduction that describes biomass and its platform chemicals; this manuscript endevours to analyze and classify the enormous literature that has been generated for biomass conversion over a new class of heterogeneous catalysts metal–organic frameworks (MOFs); the recent progress of sugar conversion over MOFs based catalysis into valuable chemicals such as 5-hydroxymethylfurfural (5-HMF) and the subsequent secondary platform chemicals such as 2,5-dimethylfuran, ethyl levulinate and lactic acid was investigated. The smart selection of MOFs’ building units and reaction solvents are critically discussed. The catalytic potential of different MOFs and composite MOFs was also investigated by demonstrating their remarkable performance with salutary examples relevant to biomass catalytic conversions into initial and secondary platform chemicals. This review also gives a state-of-the-art for the corresponding reaction kinetics and reaction mechanisms regarding the discussed sugar conversion.

This is a review of papers published in the year 2018 that focus on the synthesis, reactivity, or properties of compounds containing a carbon-transition metal double or triple bond. Highlights for the year 2018 include: (1) significant advances in the design of new precursors to carbene complex intermediates (e.g. alkynes, triazoles, and tosylhydrazones) that serve as safer alternatives to potentially hazardous diazo compounds, (2) continued vast employment of olefin metathesis for the synthesis of complex small molecules and polymers, including many examples of Z-selective and stereoretentive metathesis reactions, (3) development of biologically-inspired catalysts for carbene transfer reactions, (4) preparation of novel aromatic ring systems incorporating transition elements, (5) use of gold and platinum carbene-mediated transformations of alkynes in complex synthetic organic transformations, and (6) design of novel reaction pathways for capture of transition metal carbenoid intermediates.