Themed collection FOCUS: Metal and Metal-Containing Clusters

N-heterocyclic carbenes are structurally versatile ligands, which have strong σ-donor properties to form covalent bonds with metal centers. This frontier article provides a review on active NHC-stabilized metal complexes and clusters for photocatalytic CO₂ reduction.

Asymmetrically functionalized Anderson-type polyoxometalates were overviewed, including the key factors of various synthesis methods, separation methods, advantages of asymmetric structures, and their applications.

This review provides a classification of oxometallate–Ag cluster hybrid nanocomposites based on their array configurations and introduces the fascinating properties and cooperative effects of oxometallate and Ag clusters.

This review exhibits a comprehensive summary of uranium-containing polyoxometalates, including synthesis and structures, characterizations, properties, and applications. The development prospects and future directions are also elucidated.

An organophosphonic ligand-templated P^V–Sb^III double-heteroatom-intercalated polyoxotungstate 1 was synthesized and the ability of the 1-based genosensor to detect the β-thalassemia gene was evaluated.

Component-dependent trap sites in copper-related emission were studied using chalcogenide cluster models. In³⁺ ions in the clusters induce shallow-delocalized traps while Ga³⁺ ions are associated with carrier localization at deep-localized traps.

Presented herein is a study focusing on the effect of organic shell ligands on the configuration of the ring structure with the same nuclearity, and their photo-related applications, such as fluorescence and third-order nonlinear response.

Direct coupling of two inert CO₂ molecules to form a CO₂ dimer with strong C–C bond over the Cu⁰ atomic interfaces is proposed based on our periodic density functional theory calculations.

Pt nanoclusters anchored porous TiO₂ microspheres with abundant oxygen vacancy was developed as a highly-efficient photocatalyst for solar driven photocatalytic lignocellulosic biomass-to-H₂ conversion.

The reaction of ligand pyrene^Q–Q, Co₂(CO)₈, and Me_ntpa gave rise to a series of dinuclear cobalt–tetraoxolene compounds formulated as {[Co(Me_ntpa)]₂(pyrene^Sq–Sq)}[Co(CO)₄]₂·S (Sq = semiquinone; n = 0, S = 2C₆H₅CH₃ for 3; n = 1 for 4; n = 2, S = 2CHCl₃ for 5).

A facile approach for modifying the surface structure of discrete metal chalcogenide supertetrahedral clusters to improve their contact with MXene nanosheets, thus enhancing their photocatalytic performance.

A flexible Cu(I) coordination polymer is reported as the luminescence sensor for the detection of CH₂Cl₂. The adsorption of guest molecules lengthens the Cu⋯Cu distance, resulting in luminescent blue shifts and higher emission energy.

Elongated distance between adjacent clusters could decrease the photoinduced carrier recombination due to the prolonged intercluster charge transfer process.

This study employs diacylhydrazone-derived ligands to realize controllable construction of differentiated hexanuclear lanthanide clusters with identical cores but different template-motif arrangements for the first time.

Two isostructural metal–organic cubes were self-assembled from large-sized tetradentate ligand constructs with hexanuclear vanadium clusters. They have excellent iodine vapor adsorption properties due to large cavities and host–guest interactions.

The oxidized Pt atomic cluster-supported Au electrode (Pt_AC–O–Au) with ultra-low loading exhibits a very high mass activity, and the active site is the oxidized platinum (Pt–O).

Through rational molecular engineering, a crystal structure is transformed from a 0D cluster of K₂Sn(C₂O₄)₂·H₂O to a 1D chain of (K₂Sn₂(C₂O₄)₂F₂·H₂O), and the corresponding birefringence increases dramatically from 0.103@546 nm to 0.301@546 nm.

The first molybdovanadate cluster modified by bisphosphonate ligand with a new [Mo^VV^IVO₄] building unit is successfully synthesized. The VO bonds in this compound are demonstrated to play a pivotal role in the deep oxidation of dibenzothiophene.

A monoanionic N–P ligand L3 with a pendant dimethylamino group was designed. Species with multiple U–C bonds—a rare example of a metallafluorene containing an actinide element—and clusters with multiple U–M bonds were isolated.

A robust nanocluster of Au₄₁Cu₃₃(RS)₄₀(MeCN) (RSH is 4-fluorothiophenol) has been obtained. Rich uncoordinated copper sites on the surface lead to its extremely high catalytic activity (up to 39 269 TON) in C–O coupling reactions.

By regulating the surface dynamics of Sal-Cu/OMe-Cu motifs of a {Ti₁₀Cu₂} cluster, (Ti₁₀Cu₂)_sp and (Ti₁₀Cu₂)_cs have been achieved and characterized, and the results show the distinguishing electrical and catalytic properties of the two assemblies.

We have synthesized a drone-shaped lanthanide cluster 1, and its possible self-assembly mechanism was speculated. We observed the transition from crystalline to amorphous high-nuclear lanthanide clusters for the first time.

A polyoxoniobate decorated by Co(III)-amine complex, Na₄(H₂O)₁₅[Co(en)₃]₂{[Co(en)(Nb₆O₁₉)]₂}·34H₂O exhibits remarkable catalytic activity for urea oxidation reaction after being firmly attached to the surface of acetylene black by polyethyleneimine.

The structural changes caused by the phase transition enhance the second harmonic generatio (SHG) effect.

The unprecedented cage-shaped Gd₂₈ can be divided into the aesthetically exquisite triangle-shaped Gd₁₂ subunit and the triangle-shaped Gd₁₆ subunit, which is constructed from four Gd₃ units and four Gd₄ units.

An counterpart-shaped gallium-sulfide molecular ring with its indium alloyed one toward efficient photocatalytic dye degradation and comparable photocatalytic hydrogen production.

A “three in one” project involved atomically precise biotinylated complex, VBio-Cu^ICu^II, composed of a hydroxyl radical-producible Cu(I), a Cu(II) moiety as a GSH depletor for augmented CDT, and biotin as a cancer-targeting unit.

A kinetic study investigating the formation of a [2Fe–2S] compound, 1, with an unusually long Fe⋯Fe distance. 1 holds potential implications for the understanding of S-atom transfer reactions.

Au/Cu/PN(Pz)P complexes underwent a single-crystal-to-single-crystal (SCSC) transformation accompanied by a luminescence change from red to orange and green, and were able to detect ultralow humidity as low as 0.21 ppm.

Zero-field single-molecule magnetic behavior and proton conductivity are integrated into homochiral 3d–4f nanoscale molecules, and strong magneto-optical coupling can be realized in the meantime, resulting in strong magneto-optical Faraday effects.

A Cu^I₆ precursor sandwiched by two Cu^I₃-thiacalixarene PSBUs afforded an ultra-stable Cu^I₁₂ cluster with efficient photothermal conversion properties both in the solid and liquid states.

Four zeolite-like crystalline salts, T3-MEP and T4-MTN/DIA/LON (where MEP, MTN, DIA and LON are the topological codes), have been fabricated.

A new hybrid uranyl-silicotungstate (U₃) was synthesized and characterized. U₃ contains two kinds of Keggin-type building units and shows good catalytic activity in the synthesis of dihydropyrimidin-2(1H)-ones from aldehydes, acetoacetates, and urea.

Reported herein is a highly stable rod-packing Sc-MOF with Lewis basic bare N sites and two types of open channels demonstrating a superior CO₂ storage capacity, a remarkable separation ability for CO₂ mixtures, and prominent catalytic CO₂ cycloaddition.

We fabricate a library of binary to quinary element Keplerate clusters stabilized in a medium entropy state. Different ions follow the Irving–Williams series to be incorporated in the clusters.

The rate of O-atom defect formation on a reduced POV-alkoxide via PCET is accelerated despite weakened surface O–H bonds. Increased electron density and terminal VO basicity break classical driving force/rate scaling relationships.

The stable LCUH-100 was designed and synthesized, by incorporating chromophores into lanthanide MOFs, as a high-efficiency photocatalyst, which can rapidly and efficiently reduce Cr(VI) under visible-light irradiation and has good cycle stability.

A series of rigid–flexible-ligand functionalized lanthanide incorporated ring-shaped selenotungstates were prepared, in which a europium-containing species was employed as a fluorescence sensor to detect an anthrax biomarker with good performance.

Engineering carboxylic ligands as an unexplored while efficient strategy to modulate the optical and assembly properties of metal nanoclusters.

A hollow NiPSC electrode with a large d-spacing lattice distance has been demonstrated as an active SC electrode in a supercapacitor–battery hybrid device to achieve superior electrochemical performance.

Magnetic sustentation experiments are employed to monitor the adsorption process of a supramolecularly assembled MOF in solution.

Efficient protocols for the semihydrogenation of internal alkynes and terminal alkynols are reported using the new [Mo₃S₄Cl₃(ImNH₂)₃]⁺ complex as catalyst.

Presented herein is the discovery of the in situ synthesis of pyrazolylborates. They exhibit great adaptive coordination behaviors in aluminum oxo clusters and further provide a platform for the development of trans-chelating scorpionate analogues.

Fe/Fe₃C- and N- co-doped carbon nanotubes and NiFe hydroxide cluster was integrated directly as bifunctional catalyst for high efficiency and durable zinc-air batteries.

We report here the successful synthesis and purification of asymmetrically modified Anderson clusters, and development of a robust coupling method for precision synthesis of organic–inorganic cluster oligomers.

A highly symmetric Al₂₄ cluster with truncated metallo-cube structure is reported. As one of 13 Archimedean polyhedra, Al₂₄ is composed of eight Al₃ triangles and six Al₈ octagons. And the regulation from ringy Al₁₂ to Al₂₄ metallocage is realized.

The Brønsted basic hexaniobate is immobilized on the Lewis acidic zirconia by emulsion assisted self-assembly, the synergistic effect between the two components endows the C₁₆N-Nb₆/ZrO₂ with remarkable performance for hydrolysis of Sarin simulant.

The identification of halogen bonded-intermediates is key to understanding the precise mechanism for the generation of I₅⁻ (and I₈²⁻) ligands from I₂ and metal-coordinated I₃⁻.

A CO₂ bridged photocatalytic interface between a nickel metal–organic framework and ruthenium pyridine for high-efficiency photoreduction of diluted CO₂.

A non-centrosymmetric metal-free thiophosphate, γ-P₄S₃I₂, was successfully designed and synthesized by polymorphism strategy, and featured paralleled (P₄S₃I₂)_n molecular clusters and exhibited promising nonlinear optical (NLO) performances.

A previously undiscovered gigantic 3d–4f wheel-like nanoscale cluster, {Gd₄₄Ni₂₂}, exhibits a large magnetocaloric effect (−ΔS_m = 44.9 J kg⁻¹ K⁻¹ at 2.0 K for ΔH = 7 T).

The smallest borafullerene U@C₂₇B has been synthesized using a laser vaporization cluster source. The U atom, placed in the middle of the cage and interacting with all the 28 atoms, is formally described as highly oxidized U(VI).

Fabricating a series of thiacalix[4]arene-supported {Co/Fe}₁₆ clusters from polynuclear secondary building units facilitates the formation of efficient active sites with a Co–Fe synergistic effect for the oxygen evolution reaction.

A crystal of Zn(II) complex shows temperature-dependent 10% contraction/expansion and a continuous pyroelectric current corresponding to a scissor motion of molecules.

Heterostructured reduced-CuNiFe-MMOs nanosheets with multiphases have been fabricated and applied as a Fenton-like photocatalyst, exhibiting efficient, environmentally friendly tetracycline degradation without additional oxidants.

Relaxation of magnetization in DyM₂N@C₈₀ and Dy₂MN@C₈₀ (M = Sc, Y, La, Lu) series correlates, respectively, with the mass and size of the diamagnetic metal M.

A series of trinuclear indium–organic frameworks was synthesized and this work demonstrates that bimetallic engineering is a promising strategy for efficient CO₂ capture and electrocatalytic CO₂ conversion.

With evolution from polyoxometalate-based molecular building blocks to infinite building blocks (IBBs), a supramolecular polyoxometalate–cyclodextrin framework was constructed by an IBB strategy for multifunctional oxidative catalysis.

We present seven rare-earth derivants of mixed-polyoxoniobates, which behave as weak acids with good stability and high proton release capacity.

A wheel-shaped {Co₁₆Mo₁₆P₂₄} cluster-based 3-D crystal framework serves as an efficient bifunctional photoelectrochemical sensor for the trace determination of Cr(VI) and tetracycline.

Through a geometrically guided approach, i.e. with the aid of pyridyl modulators, the long-sought MIL-101(Mn) structure is finally achieved, which features emergent topologically correlated mixed-valence states that are apt for enzymatic catalysis.

Rh was incorporated in Fe-doped Ni₃S₂ nanosheets with the assistance of hydrogen plasma to significantly enhance the HER/OER catalytic activity. The operando evolution behavior and Janus catalytic mechanism of this catalyst were further revealed.

We are the first to achieve the directional construction of chiral lanthanide clusters by regulating the hydroxyl coordination sites at different positions on the ligands by manipulating the annular growth mechanism.

Isomers of Dy₂O@C₈₈ and Dy₂C₂@C₈₈ show a strong variation in the type and strength of Dy⋯Dy superexchange interactions and magnetization relaxation rate.

Two novel quaternary thioarsenates Cs₂ZnAs₄S₈ and [(NH₄)Cs]CdAs₄S₈ with intriguing dimensional transition have been discovered for the first time, which display variable photocurrent response and optical anisotropy.

Three new Salt-Inclusion Infrared Nonlinear Optical Crystals with Zero-dimensional [Ge3S9] Clusters.

The combination of [In₂Tm₂(μ₂-OH)₂(CO₂)₁₀(H₂O)₂] clusters and H₅BDCP ligand generated a highly robust nanoporous MOF with high catalytic performance in the cycloaddition reaction of epoxides with CO₂ and Knoevenagel condensation.

The reaction of μ₃-CCF Dy₂TiC@I_h-C₈₀ with AdN₂ affords only one [6,6]-open monoadduct along with the addition sites adjacent to the Ti⁴⁺ ion instead of the two Dy³⁺ ions, revealing the decisive role of the non-rare earth metal Ti(IV).

Two novel cyclic titanium-oxo clusters were constructed from Ti-oxo units and ferrocene connectors, and they were employed as electrode precursors to investigate their photoelectric responses.

Atomically precise alkynyl-protected copper(I) nanoclusters (CuNCs) have been prepared, and they exhibit high phosphorescence quantum yield, short lifetime, and fast radiative decay rate, which are rarely observed in atomically precise CuNCs.