Coordination Chemistry

Bis(arylimino)acenaphthene ligands were recognized as robust scaffolds for metal complexes decades ago, but their redox non-innocence as well as their potential to mediate electro- or photo-catalysis remain subjects of active research. Here, the authors review the synthesis and properties of these poly-aromatic diimine ligands complexed to nominally redox-innocent p-block elements.

The chemistry of carbon monoxide (CO) as a ligand has evolved significantly and transition-metal carbonyl complexes have been widely used as catalysts in many important catalytic processes. Here the authors comment on the recent progress of main-group element carbonyl complexes along with their future prospects.

Over the past decade, momentous progress has been made in the characterization of late actinide compounds. Here the authors highlight how advances in spectroscopic and computational tools have developed our understanding of fundamental transplutonium bonding interactions, and discuss whether covalency and heterogeneity changes in 5f-orbital bonding could be harnessed in environmentally and industrially relevant systems.

Complexes possessing coordination spheres that can accommodate nine ligand atoms typically display spherical distributions of these atoms. Here, the authors predict that M-centered [OB-B₇O₇-BO] adopts unusual heptagonal bipyramidal nonacoordination.

Metal-oxo clusters are useful building units of supramolecular assemblies. Here the authors explore the influence of NH moieties in the proximal secondary coordination sphere on the self-assembly of tetrahedral zinc-oxo clusters.

Fluorescent probes can detect metal ions with high sensitivity, but their design typically relies on a limited number of sensing mechanisms. Here the use of arene–metal-ion contact as a sensing mechanism allows ratiometric detection of metal ions across a broad wavelength range.

Photoactive ruthenium metal complexes are relevant luminescent DNA markers, but deciphering their local excited state dynamics in complex biochemical environments is challenging. Here the authors combine femtosecond and nanosecond pump-probe spectroscopy to elucidate the local hydration effects and ³MLCT relaxation dynamics of [Ru(phen)₂(dppz)]²⁺ in two G-quadruplexes.

Molecular spin processors are promising for quantum computing, but for universal applicability the available computational space needs to be expanded beyond three qubits while retaining the ability to perform universal quantum operations. Here, the authors report dissymetric molecular Gadolinium(III) dimers acting as 6-qubit quantum processors.

The properties of nano-crystalline materials depend heavily on their size, therefore, understanding early crystallization processes is crucial. Here, the relationship between phosphorescence and crystal structures of three crystallizing Au(I) complexes bearing n-alkyl chains of different lengths is studied.

Multinuclear metal complexes are common motifs in metalloenzymes and hold promising applications in homogeneous catalysis. Here an iodide-bridged binuclear palladium complex improves the efficiency of C-H nitrosation/annulation reactions through a trans effect.

Octa-coordinated complexes or ions have a bond order of seven, yet they accommodate eight lone-pairs of ligands. Here the Jellium model is demonstrated to be an appropriate description of the valence bonding structures of M(CO)₈ species, where each coordinative bond contains 7/8ths of the bonding orbitals and 1/8th non-bonding orbitals.

Strong spin-spin interactions between surface-deposited magnetic molecules are desirable for quantum computing applications. Here the authors use scanning tunneling microscopy and spectroscopy to investigate the spin-spin interactions between neighbouring porphyrazine-derivatives on Au(111).

Radionuclide pairs 44Sc/47Sc and 86Y/90Y possess great promise in the development of theranostic agents, but realizing the full potential of these isotopes necessitates improving rare-earth chelation chemistry. Here the authors show that a hydroxypyridinone-based ligand is a promising candidate for applications in this arena.

Rare earth elements are critical components of clean energy technologies, but less than 1% are recycled due to high costs of recovery. Here the authors develop a ligand that selectively precipitates rare earth elements from aqueous media as a function of pH to facilitate the separation of binary rare earth mixtures.

Rational photosensitizer design for the effective use of low-energy light is important for photofunctional materials. Here the authors develop a stacked nanocarbon photosensitizer based on a rigid polyaromatic framework, which allows efficient energy transfer to a Eu(III) center.

Permanent magnets constructed from metal ions and organic linkers using molecular design principles could bring transformative advances in areas such as energy conversion, transportation, and information storage. This comment highlights the recent discovery of a metal–organic magnet ordering at 242 °C, and discusses future research directions and possible applications involving such materials.

Preorganization is an effective strategy for f-element separation, but the complexity of extractant synthesis hinders large-scale application. Here the authors discuss an alternative strategy induced by in situ self-assembly that borrows principles of multivalent cooperativity from Nature to separate f-elements.

Water-soluble nanocontainers that can encapsulate and modulate the properties of synthetic fluorescent probes could expand the versatility of such probes in biologically relevant environments. Here, the authors encapsulate the resazurin/resorufin redox pair within a flexible palladium-based coordination cage and find that confinement drastically alters the optical and redox properties of the two dyes.

Coordination-driven self-assembly presents a key challenge of selectively targeting desired products. Here terpy-Zn complexes assemble head-to-tail, providing selective access to metallo-macrocycles

Lanthanide-based supramolecular complexes have labile and hard-topredict chemical structures. Here the authors show controlled formation of either helicates or tetrahedron shaped cages based on the interplay between the metal ionic radius and the ligand composition.

Metallo-supramolecular polymers have demonstrated promise for applications in displays, sensors, and storage devices, but control over their synthesis remains a challenge. Here, the authors report on the stepwise introduction of three different transition metals into a metallo-supramolecular polymer and highlight its potential as an electrochromic display material.

High-nuclearity lanthanide clusters can exhibit interesting properties such as magnetism, but the mechanisms by which they assemble are poorly understood. Here, the formation of two dysprosium nanoclusters containing 30 or 60 atoms is followed over time by mass spectrometry and proposed to follow a seven-step assembly mechanism.

Thermodynamic template effects are widely used in supramolecular assembly, but kinetic template effects are less well understood. Here the contributions of thermodynamic and kinetic template effects in the self-assembly of palladium metallocages are disentangled using QASAP methodology.

The hydration and ion pairing of metal-organic supramolecular cages plays a crucial role in their interaction with guests but is difficult to quantify with standard analysis. Here, the authors show that microwave microfluidics to measure the hydration and ion pairing of two tetrahedral metal-organic cages.

Mechanically interlocked molecules are widely studied, but the pathways by which they assemble are less well understood. Here the formation process of a quadruply-locked Pd₄L₈ cage is studied by NMR and mass spectrometry, with intermediates inferred by kinetic analysis.

Porphyrins have been incorporated into metal–organic frameworks in a periodic fashion in order to exploit their unique photophysical and electrochemical properties. This article reviews progress in the field, focusing on the fundamental physical properties that arise in porphyrin-based MOFs.

While the bulk structures of metal–organic frameworks can be solved by diffraction-based techniques, characterization of their local structures has been lacking. Here the authors review recent advances in (scanning) transmission electron microscopy that have made it possible to probe the local structures of MOFs at atomic resolution.

Synthetic tenability of metal organic frameworks renders them versatile platform for next-generation energy storage technologies. Here the authors provide an overview of selected MOF attributes for applications in solid-state electrolytes and battery operation in extreme environments.

Efficient electron-hole separation and carrier utilization are key factors in photosynthetic systems. Here, the authors achieve efficient charge separation following a photogenerated hole-transfer band-trap pathway in the ternary composite Pt@NH₂-UiO-66/CdS, resulting in photocatalytic hydrogen evolution with good stability and a quantum efficiency of 40.3% at 400 nm irradiation.

Detection of trimethylamine N-oxide (TMAO) can allow for early intervention of cardiovascular disease, but is challenging to achieve using conventional materials and instruments owing to it being spectroscopically silent in the UV-visible region. Here, a series of bilanthanide metalorganic frameworks functionalised with a borono group are shown to detect TMAO with high sensitivity and selectivity by exploiting the inverse emission intensity changes of the two lanthanide centres.

Determining the spatial ordering and hydrogen bonding dynamics of confined water molecules within nanopores remains challenging. Here, Raman spectroscopy and crystallographic studies show ice-like spatial ordering of unbound water molecules within the pores of the metal-organic framework HKUST-1 at room temperature.

Metal–organic frameworks have demonstrated great potential as drug delivery systems, but the biocompatibility of the MOF components is often overlooked. Here, a vitamin C and zinc-based MOF with permanent microporosity is designed, and successful loading and release of model drug urea from the MOF pores, as well as degradation of the framework, are demonstrated.

The metal-organic framework ZIF-8 has demonstrated promise for a wide range of applications, but its synthesis typically involves methodologies that are difficult or expensive to scale up. Here the authors show how the production of nano-ZIF-8 can be conducted at the 1kg scale in an economical manner through the intermediate phase ZIF-L.

Bismuth organic frameworks can display interesting phosphorescent properties, but the relationship between structure and optical activity remains underexplored. Here two bismuth organic frameworks with differing bismuth coordination number and intermetallic distance are contrasted.

Control over the morphology of porous materials is key for many applications, but can be challenging when targeting small particle sizes. Here one dimensional nano- and microstructures of zeolitic imidazolate frameworks are prepared using track-etched polycarbonate membranes as templates for interfacial synthesis.

Metal–organic frameworks have been shown to adsorb and decompose chemical warfare agents, but their mechanism of action is not completely understood. Here the authors quantitatively track the binding and decomposition product structures of nerve-agent simulant dimethyl methylphosphonate in host UiO-67 through in situ X-ray total scattering measurements, pair distribution function analysis, and density functional theory calculations.

Flexible metal–organic frameworks that undergo structural transformations upon gas sorption show great promise for applications in gas storage and separation, but accurately describing their stepped isotherms and hysteresis remains a challenge. Here, the authors introduce an empirical model to describe hysteretic MOF sorption isotherms and determine their temperature dependence, which is asymptotic at low temperatures.

The selective CO₂ absorption properties of ionic liquids make them attractive for CO₂ capture purposes, but their tendency to crystallize poorly hampers structural investigations. Here a soft crystalline material is used as a surrogate for single-crystal X-ray diffraction analysis to visualize interactions between CO₂ and NTf₂⁻, the fluorinated component that is responsible for high CO₂ solubility.

Water trapped in nanoscale spaces shows unique properties due to confinement effects. Here the authors observe an exotic state of water in the hydrophilic nanopores of porous coordination polymers.

The ability to digest and regenerate metal-organic frameworks is valuable for their application in catalysis and drug delivery, but challenging to achieve. Here, the authors develop a facile method to digest and regenerate a series of zirconium-based metal-organic frameworks using bicarbonate or carbonate salts.