Merohedral icosahedral M48 (M = CoII, NiII) cage clusters supported by thiacalix[4]arene

Stepwise assembly of thiacalix[4]arene-protected Ag/Ti bimetallic nanoclusters: accurate identification of catalytic Ag sites in CO2 electroreduction

The accurate identification of catalytic sites in heterogeneous catalysts poses a significant challenge due to the intricate nature of controlling interfacial chemistry at the molecular level. In this study, we introduce a novel strategy to address this issue by utilizing a thiacalix[4]arene (TC4A)-protected Ti-oxo core as a template for loading Ag1+ ions, leading to the successful synthesis of a unique Ag/Ti bimetallic nanocluster denoted as Ti8Ag8. This nanocluster exhibits multiple surface-exposed Ag sites and possesses a distinctive "core-shell" structure, consisting of a {Ti4@Ag8(TC4A)4} core housing a {Ti2O2@Ag4(TC4A)2} motif and two {Ti@Ag2(TC4A)} motifs. To enable a comprehensive analysis, we also prepared a Ti2Ag4 cluster with the same {Ti2O2@Ag4(TC4A)2} structure found within Ti8Ag8. The structural disparities between Ti8Ag8 and Ti2Ag4 provide an excellent platform for a comparison of catalytic activity at different Ag sites. Remarkably, Ti8Ag8 exhibits exceptional performance in the electroreduction of CO2 (eCO2RR), showcasing a CO faradaic efficiency (FECO) of 92.33% at -0.9 V vs. RHE, surpassing the FECO of Ti2Ag4 (69.87% at -0.9 V vs. RHE) by a significant margin. Through density functional theory (DFT) calculations, we unveil the catalytic mechanism and further discover that Ag active sites located at {Ti@Ag2(TC4A)} possess a higher εd value compared to those at {Ti2O2@Ag4(TC4A)2}, enhancing the stabilization of the *COOH intermediate during the eCO2RR. This study provides valuable insights into the accurate identification of catalytic sites in bimetallic nanoclusters and opens up promising avenues for efficient CO2 reduction catalyst design.

Al12Co4: a pioneering heterometallic aluminum oxo cluster with surface-exposed Co sites for the oxygen evolution reaction

We report an unprecedented heterometallic aluminum oxo cluster (AlOC) containing four surface-exposed CoII sites, designated as Al12Co4, protected by four t-butylcalix[4]arene (TBC[4]) molecules. The Al12Co4 nanocluster represents a significant advancement on multiple innovative fronts. First, it stands as an pioneering example of an AlIII-based metallocalixarene nanocluster. It is also the first instance of heterometallic AlOCs shielded by macrocyclic ligands. Notably, this cluster also holds the distinction of being the highest nuclearity Al-Co bimetallic nanocluster known to date. Additionally, by depositing Al12Co4 on carbon nanotubes (CNTs) as a supported catalyst, we investigated its electrocatalytic performance for the oxygen evolution reaction in alkaline media. To reach a 10 mA cm-2 current density in alkaline solution, the Al12Co4@CNT electrode needs overpotential as low as 320 mV.

Atomically accurate structural tailoring of thiacalix[4]arene-protected copper(II)-based metallamacrocycles

Accurate manipulation of ligands at specific sites in robust clusters is attractive but difficult, especially for those ligands that coordinate in intricate binding patterns. By linking the shuttlecock-like {Cu₄(μ₄-Cl)TC4A} motif and the phenylphosphate (PhPO₃^2-) ligand, we elaborately design and synthesize two Cu(II)-thiacalix[4]arene metallamacrocycles (MMCs), namely Cu₁₂L₃ and Cu₁₆L₄, which have regular triangular and quadrilateral topologies, respectively. While keeping the core intact, the Cl^- and PhPO₃^2- in those two MMCs, which coordinated in a μ₄-bridging fashion, can be accurately substituted with salicylate ligands. Theoretical calculations have been carried out to reveal the effect of ligand tailoring on the electronic structure of clusters. Structural regulation can affect the catalytic activity of these clusters, which has been verified by using the clusters as catalysts for selective sulfide oxidation.

From an aluminum oxo cluster to an aluminum oxo cluster organic cage

Presented herein is an example of the conversion of an aluminum oxo cluster (AlOC) to an aluminum oxo cluster organic cage (AlOCOC). We successfully synthesized the first example of an aluminum cluster-based organic cage-Al₁₂ tetrahedral cage via an Al₃ cluster. The use of 4-pyrazolecarboxylic acid plays an important role in the construction of the organic cage. Due to the presence of partially deprotonated ligands, the hydrogen-bonding interactions between the discrete tetrahedra generate porous supramolecular structures. Considering the high porosity and the abundant N-H sites, we further investigated the performance of the material towards iodine capture.

Synthesis and Study of Photothermal Properties of a Mixed-Valence Nanocluster CuI/CuII with Strong near-Infrared Optical Absorption Supported by 4-tert-Butylcalix[4]arene Ligand

The first mixed-valence nanocluster Cu^I/Cu^II with the highest percentage of Cu^II ions was synthesized by using 4-tert-butylcalix[4]arene (Calix4), with the formula DMF₂⊂[(CO₃)^2-@Cu^II₆Cu^I₃(Calix4)₃Cl₂(DMF)₅(H₃O)]•DMF (1), as a photothermal nanocluster. Its structure was characterized using single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy, and powder X-ray diffraction. In addition, the charge state and chemical composition of the nanocluster were determined using electrospray ionization spectrometry and X-ray photoelectron spectroscopy (XPS) spectrum. The results of the XPS and X-ray crystallography revealed that there are two independent Cu^II and Cu^I centers in nanocluster 1 with the relative abundances of 66.6 and 33.3% for Cu^II and Cu^I, respectively. The nanocluster contains three four-coordinated Cu^I ions with a square-planar geometry and six five-coordinated Cu^II ions with a square pyramid geometry. The nanocluster shows strong near-infrared optical absorption in the solid state and excellent photothermal conversion ability (the equilibrium temperature ∼78.2 °C) with the light absorption centers in 286-917 nm over previous reported pentanucleus Cu^I₄Cu^II clusters and Cu^II compounds.

Platonic and Archimedean solids in discrete metal-containing clusters

Metal-containing clusters have attracted increasing attention over the past 2-3 decades. This intense interest can be attributed to the fact that these discrete metal aggregates, whose atomically precise structures are resolved by single-crystal X-ray diffraction (SCXRD), often possess intriguing geometrical features (high symmetry, aesthetically pleasing shapes and architectures) and fascinating physical properties, providing invaluable opportunities for the intersection of different disciplines including chemistry, physics, mathematical geometry and materials science. In this review, we attempt to reinterpret and connect these fascinating clusters from the perspective of Platonic and Archimedean solid characteristics, focusing on highly symmetrical and complex metal-containing (metal = Al, Ti, V, Mo, W, U, Mn, Fe, Co, Ni, Pd, Pt, Cu, Ag, Au, lanthanoids (Ln), and actinoids) high-nuclearity clusters, including metal-oxo/hydroxide/chalcogenide clusters and metal clusters (with metal-metal binding) protected by surface organic ligands, such as thiolate, phosphine, alkynyl, carbonyl and nitrogen/oxygen donor ligands. Furthermore, we present the symmetrical beauty of metal cluster structures and the geometrical similarity of different types of clusters and provide a large number of examples to show how to accurately describe the metal clusters from the perspective of highly symmetrical polyhedra. Finally, knowledge and further insights into the design and synthesis of unknown metal clusters are put forward by summarizing these "star" molecules.

Synthesis of the two isomers of heteroleptic Rh12L6L'6 metal-organic polyhedra by screening of complementary linkers

We have synthesised and characterised the two possible isomers of heteroleptic trigonal antiprismatic M₁₂L₆L'₆ MOPs by screening reactions of rhodium acetate with different pairs of complementary dicarboxylate linkers. The resulting 12 new MOPs (eight of isomer A + four of isomer B) are microporous in the solid state, exhibiting Brunauer-Emmett-Teller (BET) surface areas as high as 770 m² g^-1.

A graceful break-up: serendipitous self-assembly of a ferromagnetically coupled [NiII14] wheel

The complex [NiII14(HL²)₁₂(HCOO)₁₄Cl₁₄(MeOH)(H₂O)] describes an aesthetically pleasing wheel displaying ferromagnetic nearest neighbour exchange.

Ancillary ligand-regulated Ti(IV)-based metallocalixarene coordination cages for photocatalytic H2 evolution

High-valence Ti(IV)-based metallocalixarene coordination cages that are linked by oriented ancillary ligands are unknown so far. Herein, the first family of tunable calixarene-based coordination cages of Ti(IV) with a framework formula [Ti₁₂(OⁱPr)₁₂(TBC[4])₆L₆] have been assembled from six {Ti₂(OⁱPr)₂(TBC[4])}²⁺ nodes and six pyridinedicarboxylic ligands. Furthermore, the {Ti12L6} cage showed strong photocatalytic H₂ evolution activity, and DFT studies were performed to explore its electronic structure.

Protein Frameworks with Thiacalixarene and Zinc

Controlled protein assembly provides a means to generate biomaterials. Synthetic macrocycles such as the water-soluble sulfonato-calix[n]arenes are useful mediators of protein assembly. Sulfonato-thiacalix[4]arene (tsclx ₄ ), with its metal-binding capacity, affords the potential for simultaneous macrocycle- and metal-mediated protein assembly. Here, we describe the tsclx ₄ -/Zn-directed assembly of two proteins: cationic α-helical cytochrome c (cyt c) and neutral β-propeller Ralstonia solanacearum lectin (RSL). Two co-crystal forms were obtained with cyt c, each involving multinuclear zinc sites supported by the cone conformation of tsclx ₄ . The tsclx ₄ /Zn cluster acted as an assembly node via both lysine encapsulation and metal-mediated protein-protein contacts. In the case of RSL, tsclx ₄ adopted the 1,2-alternate conformation and supported a dinuclear zinc site with concomitant encapsulation and metal-binding of two histidine side chains. These results, together with the knowledge of thiacalixarene/metal nanoclusters, suggest promising applications for thiacalixarenes in biomaterials and MOF fabrication.

Stepwise Assembly of Ag42 Nanocalices Based on a MoVI-Anchored Thiacalix[4]arene Metalloligand

Metalloligand strategy has been well recognized in the syntheses of heterometallic coordination polymers; however, such a strategy used in the assembly of silver nanoclusters is not broadly available. Herein, we report the stepwise syntheses of a family of halogen-templated Ag₄₂ nanoclusters (Ag42c-Ag42f) based on Mo^VI-anchored p-tert-butylthiacalix[4]arene (H₄TC4A) as a metalloligand (hereafter named MoO₃-TC4A). X-ray crystallography demonstrates that they are similar C₃-symmetric silver-organic nanocalices capped by six MoO₃-TC4A metalloligands, which are evenly distributed up and down the base of 42 silver atoms. These nanoclusters can be disassembled to six bowl-shaped [Ag₁₁(MoO₃-TC4A)(RS)₃] secondary building units (SBUs, R = Et or ⁿPr), which are fused together in a face-sharing fashion surrounding Cl^- or Br^- as a central anion template. The electrospray mass spectrometry (ESI-MS) indicates their high stabilities in solution and verifies the formation of the MoO₃-TC4A metalloligand, thereby rationalizing the overall stepwise assembly process for them. Moreover, Ag42c shows lower cytotoxicity and better activity against the HepG-2 cell line than MCF-7 and BGC-823. These results not only exemplify the effectiveness of a thiacalix[4]arene-based metalloligand in the assembly of silver nanoclusters but also give us profound insight about the step-by-step assembly process in silver nanoclusters.

Porous nickel and cobalt hexanuclear ring-like clusters built from two different kind of calixarene ligands – new molecular traps for small volatile molecules

The formation and structural analysis of porous hexanuclear ring-like cluster complexes built from two different kind of calixarene ligands is presented, together with their stability and vapor solvent sorption properties.

Two POM-based compounds containing Zn-capped Keggin anions as decent heterogeneous catalysts for sulfur oxidation and cycloaddition of CO2 reactions

Carbon dioxide (CO2) and the combustion of sulfide in gasoline are the main causes of air pollution. Great deal of attention has been committed to solving the problem and the...

Formation of a N/O/F-Rich and Rooflike Cluster-Based Highly Stable Cu(I/II)-MOF for Promising Pipeline Natural Gas Upgrading by the Recovery of Individual C3H8 and C2H6 Gases

Due to the ultralow amounts of C₃H₈ and C₂H₆ gases, to design and synthesize water-stable MOFs that are promising for real-world efficient pipeline natural gas (NG) upgrading by the recovery of individual C₃H₈ and C₂H₆ gases is still a great challenge. Here, a N/O/F heteroatom-rich and rooflike [Cu(II)₄Cu(I)₂(COO)₄(tetrazolyl)₆] cluster-based ultra-microporous tsi-MOF (SNNU-Bai68) was afforded as a multiple heteroatom-rich and curved-surface-shaped cluster-based ultra-microporous MOF and the first porous MOF based upon such rooflike [Cu(II)_xCu(I)_y(tetrazolyl)_z]^(2x+y-z)+ cluster. In SNNU-Bai68, the rooflike cluster was further assembled into a 1D chain secondary building block (SBB), which led to a high density of accessible potential adsorptive sites. Very interestingly, it exhibited the most promising balance of high gas adsorption uptakes at 0.01, 0.03, and 0.05 bar, high C₃H₈/CH₄, C₃H₈/C₂H₆, and C₂H₆/CH₄ adsorption selectivities, moderate adsorption enthalpies, and high water and chemical stability for pipeline natural gas upgrading by the recovery of individual C₃H₈ and C₂H₆ gases, which was further confirmed by the breakthrough experiments of the gas mixtures with/without 74% RH. Furthermore, the SC-XRD and GCMC studies revealed that the successful separation of C₃H₈, C₂H₆, and CH₄ gases in SNNU-Bai68 is due to different synergistic effects of H-bonds between the frameworks at three adsorptive sites around each rooflike cluster and those different gas molecules, which were initially described systematically by the number of H atoms from the gas molecules, the total number of H-bonds within the synergistic H-bonds, and the binding energy of the framework at an adsorption site toward the gas molecules. In addition, this work may provide a method for the construction of a multiple heteroatom-rich and curved-surface-shaped cluster-based ultra-microporous MOF as a novel approach to build MOFs with polar pore surfaces, suitable pore sizes, and unique pore shapes to maximize the synergistic H-bonds between the framework and guests.

A novel series of giant cobalt-calixarene macrocycles: ring-expansion and modulation of pore apertures through recrystallization

The design and synthesis of metallomacrocycles can be quite challenging because the assemblies of such molecular cycles are difficult to control and the products are usually unpredictable. In this work, a novel series of metallomacrocycles, denoted as {Co30-A}, {Co30-B} and {Co32-A} have been synthesized via self-assembly of p-tert-butylthiacalix[4]arene (H4TC4A) and 3,5-pyrazoledicarboxylic acid (H3pdc) with Co2+ ions under solvothermal conditions. Recrystallization of {Co32-A} under different conditions was found to form {Co32-B} and {Co32-C} that have a similar ring structure to that of {Co32-A} but have different molecular packing modes in the lattices, as well as a 40-membered ring {Co40}. These complexes represent the highest-nuclearity metallocalixarene coordination wheels reported to date. Crystallographic studies indicate that all these metallomacrocycles feature wheel-like structures with apertures varing from 11.4 to 20.3 Å. It is noteworthy that {Co32-A} exhibited good efficiency in removing RhB even at low initial concentration (10 ppm) and also excellent adsorption selectivity towards RhB over Na2Fl (RhB = Rhodamine B, Na2Fl = disodium fluorescein). This work not only makes a breakthrough in the synthesis of metallocalixarene macrocycles with high nuclearity and large apertures, but also provides a simple recrystallization approach to realize the ring-expansion and regulation of molecular packing modes of the metallomacrocycles.

Calixarene-Protected Titanium-Oxo Clusters and Their Photocurrent Responses and Photocatalytic Performances

Three photosensitive tert-butylcalix[n]arene (TBC[n], n = 4, 6, 8)-protected titanium-oxo clusters (TOCs), formulated as [Ti₄(μ₃-O)₂(TBC[4])₂(OⁱPr)₄(DEF)₂]·DEF (1, TBC[4]-Ti₄, DEF = N,N-diethylformamide), [Ti₄(μ₄-O)TBC[6](OCH₃)₉]·H₂O (2, TBC[6]-Ti₄), and [Ti₄(μ₃-O)₂(OⁱPr)₄TBC[8](DEF)₂]·DEF (3, TBC[8]-Ti₄), were successfully synthesized and characterized. Because of the generation of charge transfer from TBC[n] to the TiO core, the three TBC[n]-decorated TOCs show a broadened visible-light absorption and narrowed optical band gap based on the UV-visible spectra and density functional theory calculations. The corresponding photosensitive electrodes prepared using these three TOCs exhibit stable photocurrent responses. Furthermore, their photocatalytic performances for hydrogen evolution and methylene blue degradation were evaluated, and all of the materials display excellent photocatalytic activity and stability. The calixarene-Ti coordination is therefore an effective strategy to enlarge the visible-light absorption band of Ti-O materials and improve their photoelectric/photocatalytic performances.

Thiacalix[4]arene-supported molecular clusters for catalytic applications

Thiacalixarenes are intriguing ligands that have attracted sustained interest because of their changeable conformations and excellent coordination ability. Thiacalix[4]arene analogues, which can bind metal ions to form modular second building units, are capable of constructing molecular-based functional materials with defined structures and various applications via directional coordination assembly. Due to rich metal-sulfur bonds, thiacalix[4]arene-based molecular clusters also exhibit diverse properties compared to other clusters. In particular, the combination of thiacalixarenes with currently popular molecular architectures, such as high-nuclearity clusters and coordination cages, has shown special catalytic performances. In this perspective, the latest advances in catalytic applications of thiacalix[4]arene-based molecular clusters, including molecular clusters themselves as catalysts and coordination cages serving as reaction vessels encapsulating metal nano-components for catalysis, are highlighted.

Gas Storage in Porous Molecular Materials

Molecules with permanent porosity in the solid state have been studied for decades. Porosity in these systems is governed by intrinsic pore space, as in cages or macrocycles, and extrinsic void space, created through loose, intermolecular solid-state packing. The development of permanently porous molecular materials, especially cages with organic or metal-organic composition, has seen increased interest over the past decade, and as such, incredibly high surface areas have been reported for these solids. Despite this, examples of these materials being explored for gas storage applications are relatively limited. This minireview outlines existing molecular systems that have been investigated for gas storage and highlights strategies that have been used to understand adsorption mechanisms in porous molecular materials.

Ferromagnetic Archimedean polyhedra {Fe24M18} (M = Fe, Ni, and Mn) with tunable electron configurations

Three symmetric nanocages {Fe24M18} that mimic the Archimedean polyhedra, namely pseudo-rhombicuboctahedron, were synthesized. Their electron configurations depend highly on the changes of metal ions and the deprotonation of auxiliary ligands.

Assembly of {Co14} nanoclusters from adenine-modified Co4-thiacalix[4]arene units

An adenine-modified Co₄-thiacalix[4]arene unit can serve as a second building unit for fabrication of three Co₁₄ clusters with different structures.

Monocarboxylate-driven structural growth in Calix[n]arene-polyoxotitanate hybrid systems: utility in hydrogen production from water

A carboxylate-driven assembly strategy has been developed for the first time to build calix[n]arene-based polyoxotitanate clusters with tuneable nuclearity and structures. Photocatalytic studies revealed that these clusters exhibit structural-dependent H₂ evolution ability with a maximum rate up to 415.11 μmol h^-1 g^-1, which is almost the highest recorded in polyoxotitanate clusters.

The rise of metal-organic polyhedra

Metal-organic polyhedra are a member of metal-organic materials, and are together with metal-organic frameworks utilized as emerging porous platforms for numerous applications in energy- and bio-related sciences. However, metal-organic polyhedra have been significantly underexplored, unlike their metal-organic framework counterparts. In this review, we will cover the topologies and the classification of metal-organic polyhedra and share several suggestions, which might be useful to synthetic chemists regarding the future directions in this rapid-growing field.

Metal-Deficient Supramolecule Based on a Fivefold-Symmetric Building Block

An unprecedented cationic supramolecule [(Cp''Fe(η5 -P5 ))12 {CuNCMe}8 ]8+ 2.66 nm in diameter was selectively isolated as a salt of the weakly coordinating anion [Al{OC(CF3 )3 }4 ]- for the first time and characterized by X-ray structure analysis, PXRD, NMR spectroscopy, and mass spectrometry. Its metal-deficient core contains the lowest possible number of Cu atoms to connect 12 pentaphosphaferrocene units, providing a supramolecule with fullerene topology which, topologically, also represents the simplest homologue in the family of metal-deficient pentaphosphaferrocene-based supramolecules [{CpR Fe(η5 -P5 )}12 (CuX)20-n ]. The 12 vacant metal sites between the cyclo-P5 rings, the largest number attained to date, make this compound a facile precursor for potential inner and outer modifications of the core as well as for functionalization via the substitution of labile acetonitrile ligands.

Formation of Unsymmetrical Trinuclear Metallamacrocycles Based on Two Different Cone Calix[4]arene Macrocyclic Rings

A combination of tetrasulfonylcalix[4]arene (3-4H) together with a calix[4]arene dicarboxylate derivative 2-4H led, in the presence of MII(NO3)2 (M = Co, Ni, Zn), to the formation of three novel isostructural metallomacrocycles of formula [M3(DMF)2(μ3-H2O)-(2-2H)-3]. The structure of the prepared coordination compounds was studied in the solid state using single crystal/powder X-ray diffraction studies. The X-ray diffraction on single crystal revealed that the structure of the obtained supramolecular complexes is composed of a trinuclear metallic cluster [M3]+6 held between one di-deprotonated molecule of (2-2H)2− offering two carboxylate groups for binding metal cations and one tetra-deprotonated compound 34−, where four oxygen atoms, belonging to four deprotonated phenolic moieties and three oxygen atoms coming from three SO2 groups, are coordinated with the cluster core. Thus, an example of an easily reproducible molecular recognition pattern involving two different types of calix[4]arene based ligands, displaying different coordination moieties, and trinuclear metallic clusters, is reported here. In addition, it has been shown that the cone moieties of the calixarene also encapsulate solvent molecules.

Highly Selective Separation of C3H8 and C2H2 from CH4 within Two Water-Stable Zn5 Cluster-Based Metal-Organic Frameworks

Adopting the mixed ligands approach, two water-stable Zn₅ cluster-based MOFs, [Zn₁₀(TZ)₁₂(TADIPA)₂(DMF)₄]·DMF·6H₂O (JLU-MOF66) and [Zn₁₀(TZ)₁₂(TPTA)₂(DMA)₂]·2DMA·4H₂O (JLU-MOF67), have been constructed (H₄TADIPA = 5,5'-(1H-1,2,4-triazole-3,5-diyl)diisophthalic acid, H₄TPTA = [1,1':3',1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid, and HTZ = 1H-[1,2,3]triazole). Both compounds with [Zn₅(TZ)₆] clusters exhibit extraordinary stability (pH = 2-11) and selectivity of C₃H₈/CH₄ (308 for JLU-MOF66, and 287 for JLU-MOF67). Compared to JLU-MOF67, JLU-MOF66 with functional groups exhibits higher CO₂ and C₂H₂ uptake capacity and excellent selective separation for C₂H₂/CH₄ (86, 1:1). Such high separation and chemical stability render them as promising materials for industrial applications.

Three thiacalix[4]arene-based Cu(i) coordination polymers: catalytic activities for azide-alkyne cycloaddition reactions and luminescence properties

Three new coordination polymers, [Cu₂(CN)(L)(OCH₃)]·CH₃OH·3H₂O (1), [Cu₃(Br)₃(L)] (2) and [Cu(I)(L)]·1.5H₂O (3), have been solvothermally prepared by reacting L (5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra[(3-pyridylmethyl)oxy]-2,8,14,20-tetrathiacalix[4]arene) with Cu(i) halide. 1 and 2 exhibit layers. 3 displays a chain, a supramolecular layer constructed by hydrogen bonds. The performance of 1-3 was examined as heterogeneous catalysts for azide-alkyne cycloaddition reactions. Most strikingly, 1 and 2 show predominant efficiency with high regioselectivity and excellent recyclability. Remarkably, solids 1-3 all have luminescence characteristics under irradiation with a UV lamp.

A hierarchically assembled 88-nuclei silver-thiacalix[4]arene nanocluster

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.

Metal/N-donor-induced versatile structures and properties of seven 0D → 3D complexes based on dpq/dppz and O-bridged tricarboxylate: fluorescence and electrochemical behaviors

Seven 0D → 3D coordination polymers based on dpq/dppz and O-bridged tricarboxylates have been hydrothermally synthesized and structurally directed by metal ions, which show different electrochemical and fluorescence behaviors.

Nuclearity control in calix[4]arene-based zinc(ii) coordination complexes

Three zinc-based coordination complexes were selectively generated in the crystalline phase using a new flexible molecular “tweezers” calix[4]arene derivative ligand decorated with two appended carboxylic moieties and benzyl spacers ((3-4H)).

Metal/Carboxylate-Induced Versatile Structures of Nine 0D → 3D Complexes with Different Fluorescent and Electrochemical Behaviors

To investigate the effect of the polycarboxylates and metal ions on the assembly and structures of complexes based on a thiophene-containing bis-pyridyl-bis-amide N,N'-bis(pyridine-3-yl)thiophene-2,5-dicarboxamide (3-bptpa) ligand, nine 0D → 3D complexes of [Ni₂(3-bptpa)₄(1,2-BDC)₂(H₂O)₂] (1), [Ni(3-bptpa)(IP)(H₂O)₂]·H₂O (2), [Ni(3-bptpa)(5-MIP)(H₂O)₂]·H₂O (3), [Ni(3-bptpa)(5-NIP)(H₂O)] (4), [Ni(3-bptpa)(5-AIP)]·2H₂O (5), [Ni₂(OH)(3-bptpa)(1,3,5-BTC)]·DMA·5H₂O (6), [Cu(3-bptpa)(5-MIP)]·3H₂O (7), [Cu(3-bptpa)(5-AIP)(H₂O)_0.25]·H₂O (8), and [Cu(3-bptpa)(1,3,5-HBTC)] (9) (1,2-H₂BDC = 1,2-benzenedicarboxylic acid, H₂IP = 1,3-benzenedicarboxylic acid, 5-H₂MIP = 5-methylisophthalic acid, 5-H₂NIP = 5-nitroisophthalic acid, 5-H₂AIP = 5-aminoisophthalic acid, DMA = N,N'-dimethylacetamide, and 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid) have been hydrothermally/solvothermally synthesized and structurally characterized by IR, thermogravimetric, powder X-ray diffraction, and single-crystal X-ray diffraction. Complex 1 is a zero-dimensional (0D) bimetallic complex. Complexes 2 and 3 feature two similar one-dimensional ladderlike structures. Complex 4 displays a two-dimensional (2D) 4-connected network based on single-metallic nodes. Complex 5 shows a 2D double-layer structure containing a pair of 6³ [Ni(5-AIP)] honeycomblike sheets. Complex 6 is a 3,5-connected three-dimensional (3D) framework derived from bimetallic nodes and 6³ [Ni₂(OH)(1,3,5-BTC)] honeycomblike sheets. Complex 7 displays a 2D 4-connected grid based on bimetallic nodes. Complex 8 features a 2D double-layer structure based on two 4-connected [Cu(3-bptpa)(5-AIP)] sheets and bridging coordinated water molecules. Complex 9 is a 2D structure extended by incomplete deprotonation of 1,3,5-HBTC and 3-bptpa linkers. The effect of the metal ions and polycarboxylates on the structures of the title complexes was discussed, and the fluorescent properties of 1-9 were investigated. The carbon paste electrodes bulk-modified by complexes 3, 5, and 6-9 show different electrocatalytic activities for the oxidation of ascorbic acid as well as the reduction of hydrogen peroxide, nitrites, and bromates.

Thiacalixarene-Supported Irregular Co26 and Ni28 High-Nuclearity Clusters with Pyridyl-Diphosphonates: Strategies to Create Active Metal Sites and Fabricate Multicomponent Materials

Two new irregularity high-nuclearity clusters [Co₂₆(TC4A)₆(HL)₄Cl₄(HCOO)₄(CH₃O)₂(OH)₂(DMF)₁₀(H₂O)₅] (+ solvent) (Co₂₆) and [Ni₂₈(TC4A)₆(HL)₆(PO₄)₂(μ₃-O)₂Cl₂(CH₃OH)₁₄(H₂O)₂(DMF)₈][(CH₃NH₂CH₃)₄] (+ solvent) (Ni₂₈) have been solvothermally synthesized by p- tert-butylthiacalix[4]arene (H₄TC4A), transition metals (CoCl₂·6H₂O/NiCl₂·6H₂O), and 1-hydroxy-2-(3-pyridinyl)ethylidene-1,1-diphosphonic acid (H₅L). The clusters were structurally characterized by single crystal X-ray diffraction, PXRD, TGA, and FT-IR spectrum and Raman spectrum. Co₂₆ features a rodlike Co₂₆ core constructed by six Co₄-TC4A secondary building units (SBUs) and four HL^4- with two extra cobalt ions. Ni₂₈ cluster represents a flowerlike Ni₂₈ core built from six Ni₄-TC4A SBUs, six HL^4-, and four additional nickel ions. The multidentate risedronic acid displaying various new coordination mode bonds with SBUs to assemble two nanoclusters that enable high density possible coordinatively unsaturated metal sites (PCUMSs). Co₂₆ and Ni₂₈ clusters can be directly dispersed on carbon paper (CP) and showed extraordinary oxygen evolution reaction (OER) activity due to the larger exposed liable coordination active metal sites. The thermodecomposition of both nanoclusters at different temperatures afforded serial multicomponent complexes.

From Octahedral to Icosahedral Metal-Organic Polyhedra Assembled from Two Types of Polyoxovanadate Clusters

Design and synthesis of metal-organic polyhedra (MOPs) with targeted geometries from predetermined secondary building units (SBUs) is a long-standing challenge in chemistry and material science. Theoretical prediction shows that there are 6 possible polyhedra from the 3-coordinated, 4-coordinated octahedron ((3,4)-c octahedron) to (3,5)-c icosahedron with minimal transitivity (simplest possible). Except for one missing polyhedron (mtr) due to the unfavorable angles, we report five MOPs based on these structures, including an octahedral (3,4)-c VMOP-21 (rdo), an icosahedral (3,5)-c VMOP-25 (trc), and three intermediate derived trinodal (3,4,5)-c VMOP-22-24 (ghm, hmg, xum). Remarkably, all these MOPs obey the minimal transitivity principle and are consistent with geometrical predictions.