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The exploration of artificial metal-peptide assemblies (MPAs) is one of the most exciting fields because of their great potential for simulating the dynamics and functionality of natural proteins. However, unfavorable enthalpy changes make forming discrete complexes with large and adaptable cavities from flexible peptide ligands challenging. Here, we present a strategy integrating metal-cluster building blocks and peptides to create chiral metal-peptide assemblies and get a family of enantiopure [R-/S-Ni3L2]n (n = 2, 3, 6) MPAs, including the R-/S-Ni6L4 capsule, the S-Ni9L6 trigonal prism, and the R-/S-Ni18L12 octahedron cage. X-ray crystallography shows MPA formation reactions are highly solvent-condition-dependent, resulting in significant changes in ligand conformation and discrete cavity sizes. Moreover, we demonstrate that a structure transformation from Ni18L12 to Ni9L6 in the presence of benzopyrone molecules depends on the peptide conformational selection in crystallization. This work reveals that a metal-cluster building block approach enables facile bottom-up construction of artificial metal-peptide assemblies. The use of metal clusters to construct artificial protein-mimic structures with adaptable cavities has potential for simulating the dynamics and functionality of natural proteins. Here, the authors develop a family of chiral metal-peptide assemblies using {Ni3} clusters and flexible peptides, resulting in structures such as octahedral cages, trigonal prisms, and capsules. [ABSTRACT FROM AUTHOR]

Photosynthesis in nature uses the Mn4CaO5 cluster as the oxygen-evolving center to catalyze the water oxidation efficiently in photosystem II. Herein, we demonstrate bio-inspired heterometallic LnCo3 (Ln = Nd, Eu and Ce) clusters, which can be viewed as synthetic analogs of the CaMn4O5 cluster. Anchoring LnCo3 on phosphorus-doped graphitic carbon nitrides (PCN) shows efficient overall water splitting without any sacrificial reagents. The NdCo3/PCN-c photocatalyst exhibits excellent water splitting activity and a quantum efficiency of 2.0% at 350 nm. Ultrafast transient absorption spectroscopy revealed the transfer of a photoexcited electron and hole into the PCN and LnCo3 for hydrogen and oxygen evolution reactions, respectively. A density functional theory (DFT) calculation showed the cooperative water activation on lanthanide and O−O bond formation on transition metal for water oxidation. This work not only prepares a synthetic model of a bio-inspired oxygen-evolving center but also provides an effective strategy to realize light-driven overall water splitting. [ABSTRACT FROM AUTHOR]

The assembly of gigantic heterometallic metal clusters remains a great challenge for synthetic chemistry. Herein, based on the slow release strategy of lanthanide ions and in situ formation of lacunary polyoxometalates, two giant 3d‐4f polyoxometalate inorganic clusters [LaNi12W35Sb3P3O139(OH)6]23− (LaNi12) and [La10Ni48W140Sb16P12O568(OH)24(H2O)20]86− (La10Ni48) are obtained. The nanoscopic inorganic cluster La10Ni48 possesses a super tetrahedron structure, which can be viewed as assembly from four LaNi12 molecules encapsulating a central [La6(SbO3)4(H2O)20]6+ octahedron core. This giant aesthetic La10Ni48 tetrahedron containing 214 metal ions is the largest 3d‐4f cluster reported thus far in polyoxometalate system. More interestingly, the LaNi12 and La10Ni48 display high stability in solution and La10Ni48 displays excellent proton conductivity. [ABSTRACT FROM AUTHOR]

Incorporating metal clusters within the skeleton of the organic polymers through a click reaction cannot only effectively prepare cluster–polymer composites, but also effectively avoid the cluster aggregation. Herein, an azide‐containing lanthanide–titanium oxo cluster of Eu8Ti10‐N3 (Eu8Ti10‐N3=[Eu8Ti10(μ3‐O)14(H2O)4(OAc)2(tbba)30(paza)4(THF)2]⋅4 THF⋅8 H2O (1), Htbba=4‐tert‐butylbenzoic acid, Hpaza=4‐azidobenzoate, HOAc=acetic acid, THF=tetrahydrofuran) through an in situ solvothermal reaction of 4‐azidobenzoic acid and 4‐tert‐butylbenzoic acid. Reaction of 1 with PEG (PEG=methoxypoly(ethyleneglycol)alkyne, 2000 g mol−1) through CuI‐catalyzed click chemistry generates a lanthanide–polymer composite of Eu8Ti10‐N3@PEG (2). Investigation with IR, 1H NMR and ICP‐OES of 2 indicates that the structural integrity of 1 is maintained in 2. Study of the luminescent properties of 1 and 2 reveals that the quantum yield of 1 itself basically remains unchanged in 2. Significantly, the formation of 2 cannot only effectively prevent the cluster 1 from aggregation, but also greatly enhance its solubility and adhesion to the substrate. Owing to the solubility and adhesion of luminescent materials being the key to their practical application, present work is thus of great significance for the development of metal cluster–polymer composite luminescent materials. [ABSTRACT FROM AUTHOR]

Thiacalix[4]arenes as a family of promising ligands have been widely used to construct polynuclear metal clusters, but scarcely employed in silver nanoclusters. Herein, an anion-templated Ag88 nanocluster (SD/Ag88a) built from p-tert-butylthiacalix[4]arene (H4TC4A) is reported. Single-crystal X-ray diffraction reveals that C4-symmetric SD/Ag88a resembles a metal-organic super calix comprised of eight TC4A4− as walls and 88 silver atoms as base, which can be deconstructed to eight [CrO4@Ag11(TC4A)(EtS)4(OAc)] secondary building units arranged in an annulus encircling a CrO42− in the center. Local and global anion template effects from chromates are individually manifested in SD/Ag88a. The solution stability and hierarchical assembly mechanism of SD/Ag88a are studied by using electrospray mass spectrometry. The Ag88 nanocluster represents the highest nuclearity metal cluster capped by TC4A4−. This work not only exemplify the specific macrocyclic effects of TC4A4− in the construction of silver nanocluster but also realize the shape heredity of TC4A4− to overall silver super calix. The assembly of giant silver clusters by using macrocylic multidentate ligand remains a challenge. Here, the authors synthesize a chromate-templated 88-nuclei silver super calix and reveal the role of anion templating effects and a hierarchical assembly mechanism. [ABSTRACT FROM AUTHOR]

Abstract: A building blocks strategy is an effective approach for constructing the large molecular systems. Herein, we demonstrate that high‐resolution electro‐spray ionization mass spectrometry (HRESI‐MS) provides an effective chance to insight the assemble process of the building blocks and guides the construction of high‐nuclearity metal clusters on the basis of the reaction of Ti(OiPr)4, Eu(acac)3, and salicylic acid. The time‐dependent HRESI‐MS indicates that not only a Eu3Ti building block can be formed, but that it can further assemble into a Eu24Ti8 compound. Temperature‐dependent HRESI‐MS reveals that increase of the reaction temperature favors the formation and crystallization of the stable Eu24Ti8 structure. Single‐crystal structural analysis demonstrates that the Eu24Ti8 has a wheel‐like structure with diameter of ca. 4.1 nm and is the highest nuclearity lanthanide‐titanium oxo cluster reported to date. [ABSTRACT FROM AUTHOR]

Four high-nuclearity lanthanide–transition metal clusters, formulated as [Ln45M7(OH)68(CO3)12(CH3COO)26(CH3CH2COO)6(H2O)70]·(ClO4)25·(H2O)x (abbreviated as Ln45M7: 1, Gd45Co7; 2, Gd45Ni7; 3, Dy45Co7; 4, Dy45Ni7; x≈ 50), were obtained with the mixed protecting ligands acetate and propionate. Structural analysis shows that the cluster cationic core contains 52 metal ions featuring a bowl-like structure. 12 CO32− and 3 ClO4− anions play the role of mixed anion templates. Magnetic studies reveal that the two isotropic Gd-containing clusters Gd45Co7 and Gd45Ni7 exhibit a large magnetocaloric effect (MCE), while the anisotropic Dy-containing clusters Dy45Co7 and Dy45Ni7 show slow relaxation of magnetization. [ABSTRACT FROM AUTHOR]

A discrete 78-nucleus silver–sulfur nanocluster with a sulfate-centered multishell structure was isolated and characterized. Its crystal structure revealed 18 and 60 Ag atoms in the inner and outer shell, respectively. The inner shell of 18-nuclearity Ag atoms is a very rare convex polyhedron featuring an elongated triangular orthobicupola. The incorporation of a sulfate anion and multishell arrangement in the nanocluster led to a dramatic decrease in the band gap (Eg = 1.40 eV). Our study showed that simple anions can also induce the formation of high-nuclearity silver clusters with excellent optical properties. [ABSTRACT FROM AUTHOR]

The largest Ln-Fe metal cluster [Gd12Fe14(μ3-OH)12(μ4-OH)6(μ4-O)12(TEOA)6(CH3COO)16(H2O)8]⋅(CH3COO)2(CH3CN)2⋅(H2O)20 ( 1) and the core-shell monodisperse metal cluster of 1 a@SiO2 ( 1 a=[Gd12Fe14(μ3-OH)12(μ4-OH)6(μ4-O)12(TEOA)6(CH3COO)16 (H2O)8]2+) were prepared. Experimental and theoretical studies on the magnetic properties of 1 and 1 a@SiO2 reveal that encapsulation of one cluster into one silica nanosphere not only effectively decreases intermolecular magnetic interactions but also significantly increases the zero-field splitting effect of the outer layer Fe3+ ions. [ABSTRACT FROM AUTHOR]

Rationale Mass spectrometry (MS) has been recognized as a powerful technique to detect accurate chemical information about metal clusters. Maintaining metal clusters intact, which is a great challenge in MS analysis, was achieved in this work by choosing a suitable mass analyzer and carefully optimizing analysis parameters. Methods Electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) and electrospray ion trap mass spectrometry (ESI-IT-MS) were applied to characterize the synthesized ligand-protected metal clusters [Au6Ag2(C)(L1)6](BF4)4 (L1 = 2-diphenylphosphanyl-4-methylpyridine) ( 1) and [Au8(L2)3(L3)2](NO3)2 (L2 = bis(2-diphenylphosphinophenyl)ether, L3 = triphenyl-phosphane) ( 2). Three kinds of buffer gas (helium, mass: 2; nitrogen, mass: 28; argon, mass: 40) and various radiofrequency (RF) amplitudes (from 70 to 330) were chosen to study the fragmentation rate during the 'collision cooling' process in the ion trap analyzer. Results In the ESI-TOF-MS analysis, metal clusters 1 and 2 were mainly observed as intact clusters, which were Au6Ag2(C)(L1)6(BF4)22+, Au6Ag2(C)(L1)6(BF4)3+, Au6Ag2(C)(L1)64+ for 1 and Au8(L2)3(L3)22+ for 2. While, in the ESI-IT-MS analysis, only fragments could be found, such as Au6Ag(C)(L1)6(BF4)2+, Au6(C)(L1)62+, Au5Ag(C)(L1)42+, Au6Ag(C)(L1)63+, Au(L1)+ for 1 and Au8(L2)3(L3)2+, Au8(L2)32+, Au6(L2)32+ for 2. It is obvious that the two kinds of mass analyzers caused different MS behaviors of metal clusters. In the ion trap (IT) mass analyzer, particularly, 'collision cooling' was contributing to further dissociation of fragile compounds, in which a higher RF amplitude and a larger mass buffer gas led to more fragmentation. Conclusion In this work, intact metal clusters were obtained in ESI-TOF-MS, instead of ESI-IT-MS, in which the 'collision cooling' process caused more cluster dissociation. It was concluded that the analyzer in ESI-TOF-MS is 'softer' than that in ESI-IT-MS for metal clusters. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A general class of C3-symmetric Ag9 clusters, [Ag9S( tBuC6H4S)6(dpph)3(CF3SO3)] ( 1), [Ag9( tBuC6H4S)6(dpph)3(CF3SO3)2] ⋅CF3SO3 ( 2), [Ag9( tBuC6H4S)6(dpph)3(NO3)2] ⋅NO3 ( 3), and [Ag9( tBuC6H4S)7(dpph)3(Mo2O7)0.5]2 ⋅2 CF3COO ( 4) (dpph=1,6-bis(diphenylphosphino)hexane), with a twisted trigonal-prism geometry was isolated by the reaction of polymeric {(HNEt3)2[Ag10( tBuC6H4S)12]} n, 1,6-bis(diphenylphosphino)hexane, and various silver salts under solvothermal conditions. The structures consist of discrete clusters constructed from a girdling Ag9 twisted trigonal prism with the top and bottom trigonal faces capped by diverse anions (i.e., S2− and CF3SO3− for compound 1, 2×CF3SO3− for compound 2, 2×NO3− for compound 3, and tBuC6H4S− and Mo2O72− for compound 4). This trigonal prism is bisected by another shrunken Ag3 trigon at its waist position. Interestingly, two inversion-related Ag9 trigonal-prismatic clusters are dimerized by the Mo2O72− ion in compound 4. The twist is amplified by the bulkier thiolate, which also introduces high steric-hindrance for the capping ligand, that is, the longer dpph ligand. Four more silver-sulfur clusters (namely, compounds 5- 8) with their nuclearity ranging from 6-10 were solely characterized by single-crystal X-ray diffraction to verify the above-described synergetic effect of mixed ligands in the construction of Ag9 twisted trigonal prisms. Surprisingly, only cluster 1 emits yellow luminescence at λ=584 nm at room temperature, which may be attributed to a charge transfer from the S 3p orbital to the Ag 5s orbital, or mixed with metal-centered (MC) d10→d9s1 transitions. Upon cooling from 300 to 80 K, the emission intensity was enhanced along with a hypsochromic shift. The good linear relationship between the maximum emission intensity and the temperature for compound 1 in the range of 180-300 K indicates that this is a promising molecular luminescent thermometer. Furthermore, cyclic voltammetric studies indicated that the diffusion- and surface-controlled redox processes were determined for compounds 1 and 3 as well as compound 4, respectively. [ABSTRACT FROM AUTHOR]

Two high-nuclearity 3d–4f clusters Ln24Zn4 (Ln = Gd and Sm) featuring four Ln6 octahedra encapsulating a Zn4 tetrahedron were obtained through the self-assembly of Zn(OAc)2 and Ln(ClO4)3. Quantum Monte Carlo (QMC) simulations show the antiferromagnetic coupling between Gd3+ ions. Studies of the magnetocaloric effect (MCE) show that the Gd24Zn4 cluster exhibits the entropy change (−ΔSm) of 31.4 J kg−1 K−1. [ABSTRACT FROM AUTHOR]

A novel mixed-valent Agi/Ag0Th-Ag34cage was obtained by a one-pot ultrasonic reaction. In the shell of the cage, CO32−anion is derived from atmospheric CO2and adopts a rare μ6bridging mode to link the Agiions. In the core of the cage, an unprecedented neutral metal cluster with six zero-valent silver atoms is encapsulated. [ABSTRACT FROM AUTHOR]

A nanosized heterometallic cluster containing 60 La(iii) and 76 Ni(ii) ions, which are arranged into a four-shell, nest-like framework structure, was obtained by the hydrolytic reaction of the mixed La(NO3)3–Ni(NO3)2system using iminodiacetate as an ancillary ligand to control the hydrolysis. [ABSTRACT FROM AUTHOR]

A cage-shaped 3d–4f heterometallic ferromagnetic cluster, consisting of six Ni(ii) and three La(iii) ions, was synthesized by microwave irradiation. The magnetic susceptibilities of the cluster were fitted with the help of the program MAGPACK, revealing that the magnetic exchange in the cluster is closely related to the coordination mode and spatial distribution between the metal ions. [ABSTRACT FROM AUTHOR]

Although there has been an upsurge of interest in anisotropic assembly of inorganic nanoparticles, atomically precise self-assembly of anisotropic metal clusters is extremely rare. Herein, we presented two novel silver nanoclusters, Ag52 (SD/Ag23) and Ag76 (SD/Ag24), which are interiorly templated by five MoO42- and a pair of Mo6O228- anions, respectively, and coprotected by bridging RSH and terminal diphosphine ligands exteriorly. Regiospecific distribution diphosphine ligands on the surface and the arrangement of multiple molybdate templates within the nanoclusters synergetically tailor their shapes to anisotropic oblate spheroid and elongated rod, respectively. This work not only open up new avenues for the synthesis of silver nanoclusters with novel metal skeleton shapes and anisotropic surface structures but also give important insights for the anisotropic growth of silver nanoclusters through surface modifications or/and template organizations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lanthanide-containing clusters (LnCC) as unique catalysts for water splitting and CO 2 conversion are summarized. • Typical examples are illustrated from structures-properties-mechanisms perspective. • The current challenges and the development prospects for LnCC catalysts are outlined. Water splitting and CO 2 conversion involving the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), overall water splitting, CO 2 reduction, and CO 2 chemical fixation are promising strategies to alleviate the energy crisis and excessive CO 2 emissions. Lanthanide-containing clusters (LnCCs) are emerging as unique catalysts for these reactions owing to their unparalleled advantages such as their unique electronic structures, high coordination numbers, abundant coordination geometries, and adjustable crystal structures. In this review, we summarize recent progress made in the catalytic application of LnCCs, including lanthanide clusters, lanthanide–transition metal clusters, lanthanide-cluster-based metal–organic frameworks, and cluster composites for water splitting and CO 2 conversion. In particular, we emphasize the synthesis, crystal structure, and catalytic mechanism of these complexes, as well as their synergistic effects in catalytic water splitting and CO 2 conversion reactions. Moreover, based on issues discovered in the current applications of LnCCs, we provide our own perspectives for future research in this field. [ABSTRACT FROM AUTHOR]

Threeisomorphic decanuclear heterometallic 3d–4f Ln2Cu8clusters, formulated as [Ln2Cu8(μ2-OH)2(μ3-OH)2(ClO4)2(HTMHSA)4(H2O)10]·15H2O (Ln = La (1,La2Cu8); Ln = Gd (2, Gd2Cu8); Ln = Dy (3, Dy2Cu8), H5TMHSA =3-[N-tris(hydroxymethyl)methylamino]-2-hydroxyprop-anesulfonicacid), were obtained through the reaction of H5TMHSA, Ln(ClO4)3, and Cu(NO3)2·3H2O. The present three Ln2Cu8compoundsare rare examples of alkylsulfonate-based polynuclear 3d–4fclusters. Magnetic studies indicate that the cluster La2Cu8exhibits antiferromagnetic behavior, Gd2Cu8displays ferromagnetic behavior and a large magnetocaloriceffect at low temperature, while Dy2Cu8showsslow magnetic relaxation. [ABSTRACT FROM AUTHOR]

A discretedihalide–decahydrate cluster of [X2(H2O)10]2–has beenobserved in a solid-state structure of {[Na2(H2O)6(H2O@TMEQ[6])]·2(C6H5NO3)}X2(H2O)10} (TMEQ[6] = α,α′,δ,δ′-tetramethylcucurbit[6]uril;X = Cl (1), Br (2)). Its structure can beviewed as a connection of two [X(H2O)3]−clusters with a uudd water tetramer throughhydrogen-bonding interactions. [ABSTRACT FROM AUTHOR]

Abstract: The ultrasonic reaction of Lawesson''s reagent (2,4-bis(4-methoxyphenyl)-1,3-dithiadiphosphetane-2,4-disulfide, LR) with Ag(OAc) and Ph3P (triphenylphosphane) gave an Ag20 cluster {[Ag20(ArP(OEt)S2)6(ArPOS2)6(Ph3P)8]·2(OAc)·8(H2O)·(CHCl3)} (1) (Ar=4-methoxyphenyl). The core of this cluster is an Ag-based propeller comprised of one triangle central axis and three distorted rectangle leaves. The bipodal and tripodal P/S-containing ligands were generated from in situ P–S bond cleavage and P–O bond formation process. [Copyright &y& Elsevier]

Abstract: A series of AuC n − clusters were generated by laser vaporization on time-of-flight mass spectrometer and the abundance of AuC n − display odd–even alternation with even-n clusters being relatively more abundant. Density functional studies at B3LYP level reveal that even-n AuC n − clusters adopt a 1Σ ground state with a linear geometry for n =2, and a 1A′ ground state with bent chain geometries for n =4, 6, 8, 10, and 12. The geometric change from linear geometry of AuC2 − to bent geometry of AuC n − (n =4, 6, 8, 10, 12) is rationalized by the Mulliken–Walsh model. On the other hand, the odd-n AuC n − clusters adopt bent chain geometries in 1A′ ground states for n =3 and 5, and in 3A″ ground state for n =7, 9, and 11, as well as 3Σ ground state for n =1. This irregular stability is dependent on the energy gap between HOMO and LUMO. After combination of even-n and odd-n AuC n −, the calculated incremental energy and vertical detachment energy (VDE) demonstrate that even-n AuC n − are more stable than neighboring odd-n ones, which is in agreement with the observed odd–even alternation of the TOF signal intensities. [Copyright &y& Elsevier]