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Supramolecular assemblies have gained tremendous attention due to their ability to catalyze reactions with the efficiencies of natural enzymes. Using ab initio molecular dynamics, we identify the origin of the catalysis by the supramolecular capsule Ga 4 L 6 12− on the reductive elimination reaction from gold complexes and assess their similarity to natural enzymes. By comparing the free energies of the reactants and transition states for the catalyzed and uncatalyzed reactions, we determine that an encapsulated water molecule generates electric fields that contributes the most to the reduction in the activation free energy. Although this is unlike the biomimetic scenario of catalysis through direct host-guest interactions, the electric fields from the nanocage also supports the transition state to complete the reductive elimination reaction with greater catalytic efficiency. However it is also shown that the nanocage poorly organizes the interfacial water, which in turn creates electric fields that misalign with the breaking bonds of the substrate, thus identifying new opportunities for catalytic design improvements in nanocage assemblies. Supramolecular catalytic assemblies attract enormous interest due to their activity that rivals natural enzymes. Using ab initio molecular dynamics, the authors show that a gold catalyst in a Ga 4 L 6 12 - nanocage, while impeded by reorganization energy, is accelerated by hosting a catalytic water molecule.

Lanthanide (Ln) elements are generally found in the oxidation state +II or +III, and a few examples of +IV and +V compounds have also been reported. In contrast, monovalent Ln(+I) complexes remain scarce. Here we combine photoelectron spectroscopy and theoretical calculations to study Ln-doped octa-boron clusters (LnB 8 − , Ln = La, Pr, Tb, Tm, Yb) with the rare +I oxidation state. The global minimum of the LnB 8 − species changes from C s to C 7v symmetry accompanied by an oxidation-state change from +III to +I from the early to late lanthanides. All the C 7v -LnB 8 − clusters can be viewed as a monovalent Ln(I) coordinated by a η 8 -B 8 2− doubly aromatic ligand. The B 7 3− , B 8 2− , and B 9 − series of aromatic boron clusters are analogous to the classical aromatic hydrocarbon molecules, C 5 H 5 − , C 6 H 6 , and C 7 H 7 + , respectively, with similar trends of size and charge state and they are named collectively as “borozenes”. Lanthanides with variable oxidation states and magnetic properties may be formed with different borozenes. The most common oxidation state for lanthanides is +3. Here the authors use photoelectron spectroscopy and theoretical calculations to study half-sandwich complexes where a lanthanide center in the oxidation state +1 is bound to an aromatic wheel-like B 8 2- ligand.

The discovery of borospherenes unveiled the capacity of boron to form fullerene-like cage structures. While fullerenes are known to entrap metal atoms to form endohedral metallofullerenes, few metal atoms have been observed to be part of the fullerene cages. Here we report the observation of a class of remarkable metallo-borospherenes, where metal atoms are integral parts of the cage surface. We have produced La 3 B 18 – and Tb 3 B 18 – and probed their structures and bonding using photoelectron spectroscopy and theoretical calculations. Global minimum searches revealed that the most stable structures of Ln 3 B 18 – are hollow cages with D 3 h symmetry. The B 18 -framework in the Ln 3 B 18 – cages can be viewed as consisting of two triangular B 6 motifs connected by three B 2 units, forming three shared B 10 rings which are coordinated to the three Ln atoms on the cage surface. These metallo-borospherenes represent a new class of unusual geometry that has not been observed in chemistry heretofore. Borospherenes are the boron-based analogs of fullerene cages. Here, the authors report a class of Ln 3 B 18 – metallo-borospherenes with unusual spherical trihedron geometry, in which the lanthanide atoms surprisingly form a part of the cage surface.

Optimizing the catalyst-electrolyte interface structure is crucial for enhancing the performance of electrochemical alkaline hydrogen evolution reaction. Traditional approaches typically focus on regulating the thermodynamic barriers of adsorption and desorption for reactants, intermediates, and ions at active sites on the solid electrode surface. However, the structure of the electrical double layer influences the concentration of intermediates, adsorption energy, and surface reaction kinetics. Here, we dynamically construct a dense epitaxial hydroxide layer on nickel molybdate, forming an effective protective barrier to prevent molybdenum leaching and enhance material stability. This optimization enhances local electric field increasing the concentration of hydrated potassium ions within the outer Helmholtz plane. As a result, the interfacial hydrogen-bond network improves, water availability on the catalyst surface increases, and reaction kinetics accelerate. The optimized material operates stably for 1400 h at a current density of 0.45 A cm −2 in an industrial alkaline electrolyzer. Our dual-optimization strategy of dynamically constructing an epitaxial catalytic layer offers valuable insights for developing stable, high-current-density electrocatalytic materials. Alkaline hydrogen production needs stable catalysts, but the electrical double layer is overlooked. Here, the authors report a dense epitaxial hydroxide layer that strengthens the double layer, prevents catalyst leaching, and enhances material stability for 1,400 h in an industrial electrolyzer.

Elemental boron and its compounds exhibit unusual structures and chemical bonding owing to the electron deficiency of boron. Joint photoelectron spectroscopy and theoretical studies over the past decade have revealed that boron clusters possess planar or quasi-planar (2D) structures up to relatively large sizes, laying the foundations for the discovery of boron-based nanostructures. The observation of the 2D B 36 cluster provided the first experimental evidence that extended boron monolayers with hexagonal vacancies were potentially viable and led to the proposition of ‘borophenes’ — boron analogues of 2D carbon structures such as graphene. Metal-doping can expand the range of potential nanostructures based on boron. Recent studies have shown that the CoB 18 − and RhB 18 − clusters possess unprecedented 2D structures, in which the dopant metal atom is part of the 2D boron network. These doped 2D clusters suggest the possibilities of creating metal-doped borophenes with potentially tunable electronic, optical and magnetic properties. Here, we discuss the recent experimental and theoretical advances in 2D boron and doped boron clusters, as well as their implications for metalloborophenes. The unusual electronic characteristics of boron atoms lead boron clusters to adopt a wide variety of structural arrangements, most of which are 2D. This Perspective discusses the possibility of expanding the range of boron-based 2D structures by metal doping, as well as the use of the resulting clusters for conceptualizing metalloborophenes.

While main group elements have four valence orbitals accessible for bonding, quadruple bonding to main group elements is extremely rare. Here we report that main group element boron is able to form quadruple bonding interactions with iron in the BFe(CO) 3 - anion complex, which has been revealed by quantum chemical investigation and identified by mass-selected infrared photodissociation spectroscopy in the gas phase. The complex is characterized to have a B-Fe(CO) 3 − structure of C 3v symmetry and features a B-Fe bond distance that is much shorter than that expected for a triple bond. Various chemical bonding analyses indicate that the complex involves unprecedented B≣Fe quadruple bonding interactions. Besides the common one electron-sharing σ bond and two Fe→B dative π bonds, there is an additional weak B→Fe dative σ bonding interaction. This finding of the new quadruple bonding indicates that there might exist a wide range of boron-metal complexes that contain such high multiplicity of chemical bonds. While main group elements possess four valence orbitals that are accessible for bonding, quadruple bonding to main group elements is very rarely observed. Here the authors report that boron is able to form four bonding interactions with iron in the BFe(CO) 3 - anion complex.

Water under nanoconfinement at ambient conditions has exhibited low-dimensional ice formation and liquid–solid phase transitions, but with structural and dynamical signatures that map onto known regions of water’s phase diagram. Using terahertz (THz) absorption spectroscopy and ab initio molecular dynamics, we have investigated the ambient water confined in a supramolecular tetrahedral assembly, and determined that a dynamically distinct network of 9 ± 1 water molecules is present within the nanocavity of the host. The low-frequency absorption spectrum and theoretical analysis of the water in the Ga₄L₆12− host demonstrate that the structure and dynamics of the encapsulated droplet is distinct from any known phase of water. A further inference is that the release of the highly unusual encapsulated water droplet creates a strong thermodynamic driver for the high-affinity binding of guests in aqueous solution for the Ga₄L₆12− supramolecular construct.

Although polylactic acid is a promising biodegradable plastic, its slow degradation under natural conditions, microplastic formation, and CO 2 emissions during decomposition undermine its sustainability. Photoreforming offers a promising strategy for polylactic acid conversion; however, current methods suffer from sluggish kinetics and low selectivity. Here, we design a Ni single-atom catalyst anchored on CdS (Ni/CdS) to enable alkali-free photoreforming of real polylactic acid plastic waste under mild conditions. Ni single atom sites facilitate sequential cleavage of α-OH and C α -H bonds, enabling efficient H 2 evolution and significantly improving the yield and selectivity of polylactic acid conversion to H 2 and pyruvic acid, achieving an apparent quantum efficiency of 46%. Furthermore, we successfully scaled up the synthesis of Ni/CdS and implemented a square-meter-scale reaction system, demonstrating stable outdoor photoreforming of real polylactic acid plastic waste under sunlight. This work paves a promising pathway for solar-driven upcycling of polylactic acid plastic waste. A Ni single-atom catalyst on CdS efficiently converts polylactic acid bioplastic into hydrogen and valuable chemicals using sunlight, offering a sustainable strategy for bioplastic waste recycling.

Electrocatalysis provides a sustainable alternative route to produce nitrogen-containing molecules. However, poor carbon-nitrogen (C-N) coupling selectivity and limited current density pose challenges to its widespread adoption. Herein, we introduce a carbon-defect enhanced 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) mediated tandem process to tackle both problems. Our hetero-homogeneous system achieves a Faraday efficiency of ~99% with industrial-level current density of ~0.6 A·cm −2 for urotropine electrosynthesis. In situ near ambient pressure X-ray photoelectron spectroscopy and quasi in situ electron paramagnetic resonance reveal that the boosted activity originated from the oxidation of TEMPOH on the carbon defective sites, which accelerates the redox cycling of the molecular mediator for urotropine formation. This work highlights the catalytic effect of carbon defects on the redox cycling of TEMPO, improves both the selectivity and the rate of the electrocatalytic C-N coupling reaction, and offers insights for designing efficient electrochemical mediated oxidation processes and C-N coupling reactions. The authors demonstrate a TEMPO-mediated urotropine electrosynthesis that is accelerated by defective carbon, as the vacancy defects transfer the oxidation of TEMPOH from a sluggish outer sphere process into a rapid inner sphere mechanism via adsorption.

Boron, the neighbor element to carbon in the periodic table, is characterized by unique electron deficiency that fosters multicenter delocalized bonding, contributing to its diverse chemistry. Unlike carbon cages (fullerenes), which preserve their structural integrity under endohedral or exohedral doping, larger boron cages (borospherenes) exhibit diverse structural configurations. These configurations can differ from those of pure boron cages and are stabilized by various metals through unique metal–boron bonding, resulting in a variety of metalloborospherenes. Due to boron’s electron deficiency, metalloborospherenes exhibit fascinating chemical bonding patterns that vary with cluster size and the type of metal dopants. This review paper highlights recent advancements in metalloborospherene research, drawing comparisons with metallofullerenes, and focuses on the use of transition metals, lanthanides, and actinides as dopants across various cage dimensions.