Size Of Nanoclusters Research Articles

Electrostatic Assembly of Gold Nanoclusters in Reverse Emulsion Enabling Nanoassemblies with Tunable Structure and Size for Enhanced NIR-II Fluorescence Imaging.

The precise control of the assembly structure and size of gold nanoclusters (AuNCs) can potentially amplify their near-infrared II (NIR-II) fluorescence imaging and targeting properties. However, the conventional electrostatic assembly of AuNCs and charged molecules faces challenges in balancing the inherent electrostatic repulsions among charged units and regulating the diffusion of assembly units. These difficulties limit precise control over assembly size and structure, along with limited options for coassembled molecules, thereby restricting imaging properties and targeting capability. To circumvent this challenge, we developed a reverse emulsion-confined electrostatic assembly method. This technique efficiently constructs AuNC nanoassemblies with diverse coassembled molecules, allowing for the fine-tuning of assembly size and structure, including both core-satellite and homogeneous AuNC nanoassemblies. The development of two distinct nanoassemblies can be partially attributed to the varying diffusive rates of AuNCs or the AuNCs/polymer complex within the fused emulsion droplets. This variance arises from steric hindrances encountered during the emulsion fusion process. Interestingly, core-satellite nanoassemblies exhibit the strongest NIR-II fluorescence enhancement. Finally, the introduction of a hyaluronic acid coating on the surfaces of nanoassemblies with varying sizes enables the nanoprobes to achieve enhanced lymph node imaging through size modulation and macrophage targeting, which are used for surgical navigation to remove lymph node metastases. We envision that this self-assembly strategy can be extended to a wide range of electrostatic assembly systems for the development of multicomponent functional materials.

Ni/V-MgnHm nanoclusters: Recent advances toward improving the dehydrogenation thermodynamics for efficient hydrogen storage

Understanding the properties of solid-state materials at the nanoscale is a crucial scientific endeavor in the pursuit of a sustainable energy future. Since magnesium hydride is the most practical material for hydrogen storage, research is still ongoing to reduce the enthalpy for dehydrogenation. In this computational theory, we systematically investigated the enthalpy of dehydrogenation of MgnHm nanoclusters of different sizes (0.5–2.8 nm) through density functional theory (DFT) and ab-initio molecular dynamic (AIMD) simulations. Our results revealed that increasing the MgnHm nanocluster size can remarkably improve the formation energy compared to the MgH2-bulk stabilization; the formation energy shifted from −65.12 kJ/mol for (0.5 nm)-MgnHm nanocluster to −51.37 kJ/mol for (2.8 nm)-MgnHm nanocluster. As compared to bulk phase, the lower stability of the nanoclusters indicates that it is much easier to desorb hydrogen from the surface. According to the effects of compressive/tensile strains, (2.8 nm)-MgnHm nanocluster does not improve the dehydrogenation temperature in the desired direction. Unlike metal doping, 9.10%@Ni and 10.14%@V-doped (2.8 nm)-MgnHm nanocluster exhibit formation energies of −47.27 and −46.34 kJ/mol with calculated desorption temperatures of 362.89 and 355.75 K, respectively, which ensures the room temperature applicability of this hydrogen storage material.

Anchoring ultrafine Au nanoclusters on sulfonate groups functionalized carbon matrix for efficient catalytic reduction of nitrophenol

Despite immense research efforts in the field of Au supported on carbon matrix, the rational design and fabrication of ultrafine Au/carbon matrix nanocatalysts with effective reactivity and high stability are still challenging. The main obstacles are faced with adjusting the size of Au nanoclusters and strengthening the bond of Au and carbon. In this work, sulfonate groups (−SO3H) introduced onto activated coke (AC) matrix was prepared for steadily anchoring ultrafine Au nanoclusters (∼2 nm). The obtained Au/SO3H-AC exhibited superior reactivity for 4-nitrophenol reduction within 3 min using NaBH4 as reducing agent. The superior performance and stability are attributed to the − SO3H groups with hydrophilic property, benefiting for substrates readily dispersion and for Au species (including oxidized Au+ and Au3+) bind and stabilization, possibly by tightly interacting with the O atoms bound to S atom of − SO3H. In addition, several lines of evidence demonstrate the oxidized Au species can serve as electron relay system, ensuring the sustained reaction. Given that the Au nanoclusters in this study have superior reactivity and stability, this work proposes a novel strategy for preparing other supported metal nanocomposites.

How precisely are solute clusters in RPV steels characterized by atom probe experiments?

Atom probe tomography (APT) is a powerful microscopy technique to characterize nano-sized clusters of the alloying elements in the bulk of reactor pressure vessel (RPV) steels. These clusters are known to dominantly determine the evolution of mechanical properties under irradiation. The results are conventionally summarized as the overall number density N and the average diameter D of the solute clusters identified in the material. Here, we illustrate that these descriptors are intrinsically imprecise because they are steered by the parameters involved in the measurement and data processing, some of which are directly under the control of the operators, but some others not. Consequently, a direct comparison between data derived at different laboratories is compromised, and key trends such as the evolution with dose, are masked. This study relies on a state-of-the-art physical model for neutron irradiation in steels to make reliable estimates of the microstructure before the measurement is performed, which allows the prediction of the population of solute clusters that are not seen by APT. We mimic APT measurements from simulated microstructures, performing a detailed study of the effects of the parameters of the analysis. We show that the values of N and D reported in the scientific literature can be matched by the predictions of our theoretical model only if specific sets of parameters are used for each laboratory that issued the measurements. We also show that if, on the contrary, all studied cases are analyzed in a consistent way, the scatter of N and D values is reduced. Specifically, we find that the average diameter D is nearly a constant value with dose, independently of the material's chemical compositions, while N increases with dose, but is also influenced by other variables. The approach we developed and used proves to have added value as complement to APT experiments in reactor pressure vessel steels.

Kinetics of enantioselective heterogeneous nanocatalysis with limited cluster occupancy: Beyond the coverage concept

Theoretical analysis is presented for kinetics of enantioselective reactions on nanocatalysts, when the cross-section of the reacting molecules and the non-reacting modifiers is similar to the size of nanoclusters and only two or three molecules can be adsorbed on a cluster. The rate expressions have been derived, considering the exact configurations of the reactants and a non-reactive modifier, rather than utilizing the classical Langmuirian methodology of the surface coverage. The developed approach was used to explain rate acceleration, enantioselectivity and enantiomeric excess as a function of the modifier concentration, as well as the nonlinear behavior showing even maxima of enantiomeric excess for mixtures of modifiers.

Microstructure Evolution and Creep Properties of AZ61 Magnesium Matrix Composites Reinforced with Bimodal-Sized SiC Particles

In the scope of this exploration, AZ61 magnesium matrix composites fortified with bimodal size SiC particles were synthesized using ultrasonic-assisted mixing in the semi-solid state, which exhibited optimal grain refinement and exceptional creep resistance. We examined the impact of bimodal SiC particles on the microscopic structure and creep deformation of the resulting composites. Our findings indicated that incorporating bimodal SiC particles resulted in the refinement of the matrix grains and alteration of the morphology of the Mg17Al12 phase. Furthermore, the micron-sized SiC particles exhibited a typical necklace-like particle distribution around the grain boundaries of the bimodal SiC particle/AZ61 composites, while the nano-sized SiC particles were mainly located around the micron-sized particles. As the volumetric percentage of micron SiC particles increased, the quantity of nano-sized particle clusters diminished noticeably. Creep analysis at 200 °C and 50 MPa revealed that the creep life of M−6+N−1 composite was increased by 111.9% compared to the AZ61 alloy. Additionally, the M−6+N−1 combination exhibited a significantly lower steady-state creep rate compared to the matrix alloy, with a reduction of approximately 11 times. These results indicate that the bimodal SiC particle/AZ61 composites have superior creep resistance, which is a consequence of the grain refinement and grain boundary pinning effects of SiC particles.

An Atom-Precise Understanding of DNA-Stabilized Silver Nanoclusters.

ConspectusDNA-stabilized silver nanoclusters (AgN-DNAs) are sequence-encoded fluorophores. Like other noble metal nanoclusters, the optical properties of AgN-DNAs are dictated by their atomically precise sizes and shapes. What makes AgN-DNAs unique is that nanocluster size and shape are controlled by nucleobase sequence of the templating DNA oligomer. By choice of DNA sequence, it is possible to synthesize a wide range of AgN-DNAs with diverse emission colors and other intriguing photophysical properties. AgN-DNAs hold significant potential as "programmable" emitters for biological imaging due to their combination of small molecular-like sizes, bright and sequence-tuned fluorescence, low toxicities, and cost-effective synthesis. In particular, the potential to extend AgN-DNAs into the second near-infrared region (NIR-II) is promising for deep tissue imaging, which is a major area of interest for advancing biomedical imaging. Achieving this goal requires a deep understanding of the structure-property relationships that govern AgN-DNAs in order to design AgN-DNA emitters with sizes and geometries that support NIR-II emission.In recent years, major advances have been made in understanding the structure and composition of AgN-DNAs, enabling new insights into the correlation of nanocluster structure and photophysical properties. These advances have hinged on combined innovations in mass characterization and crystallography of compositionally pure AgN-DNAs, together with combinatorial experiments and machine learning-guided design. A combined approach is essential due to the major challenge of growing suitable AgN-DNA crystals for diffraction and to the labor-intensive nature of preparing and solving the molecular formulas of atomically precise AgN-DNAs by mass spectrometry. These approaches alone are not feasibly scaled to explore the large sequence space of DNA oligomer templates for AgN-DNAs.This account describes recent fundamental advances in AgN-DNA science that have been enabled by high throughput synthesis and fluorimetry together with detailed analytical studies of purified AgN-DNAs. First, short introductions to nanocluster chemistry and AgN-DNA basics are presented. Then, we review recent large-scale studies that have screened thousands of DNA templates for AgN-DNAs, leading to discovery of distinct classes of these emitters with unique cluster core compositions and ligand chemistries. In particular, the discovery of a new class of chloride-stabilized AgN-DNAs enabled the first ab initio calculations of AgN-DNA electronic structure and present new approaches to stabilize these emitters in biologically relevant conditions. Near-infrared (NIR) emissive AgN-DNAs are also found to exhibit diverse structures and properties. Finally, we conclude by highlighting recent proof-of-principle demonstrations of NIR AgN-DNAs for targeted fluorescence imaging. Continued efforts may future push AgN-DNAs into the tissue transparency window for fluorescence imaging in the NIR-II tissue transparency window.

Twisted and Disconnected Chains: Flexible Linear Tetracuprous Arrays and a Decanuclear CuI Cluster as Blue- and Green/Yellow-Light Emitters.

Defined arrays of transition metal ions embedded in tailored polydentate ligand scaffolds allow for a systematic design of their physical properties. Such molecular strings of closed-shell transition metal centers are particularly interesting for Group 11 metal ions in the oxidation state +1 if they undergo metallophilic d10···d10 contact interactions since these clusters are oftentimes efficient photoluminescence (PL) emitters. Copper is particularly attractive as a sustainable earth-abundant coinage metal source and because of the ability of several CuI complexes to serve as powerful thermally activated delayed fluorescence (TADF) emitters in molecular/organic light-emitting devices (OLEDs). Our combined synthetic, crystallographic, photophysical, and computational study describes a straight tetracuprous array possessing a centrally disconnected CuI2···CuI2 chain and a continuous helically bent CuI4 complex. This molecular helix undergoes a facile rearrangement in diethyl ether solution, yielding an unprecedented nanosized CuI10 cluster (2.9 × 2.0 nm) upon crystallization. All three clusters show either bright blue phosphorescence, TADF, or green/yellow multiband phosphorescence with quantum yields between 6.5 and 67%, which is persistent under hydrostatic pressure up to 30 kbar. Temperature-dependent PL investigations in combination with time-dependent density-functional theory (TD-DFT) calculations and void space analyses of the crystal packings complement a comprehensive correlation between the molecular structures and photoluminescence properties.

Single-gold etching at the hypercarbon atom of C-centred hexagold(I) clusters protected by chiral N-heterocyclic carbenes

Chemical etching of nano-sized metal clusters at the atomic level has a high potential for creating metal number-specific structures and functions that are difficult to achieve with bottom-up synthesis methods. In particular, precisely etching metal atoms one by one from nonmetallic element-centred metal clusters and elucidating the relationship between their well-defined structures, and chemical and physical properties will facilitate future materials design for metal clusters. Here we report the single-gold etching at a hypercarbon centre in gold(I) clusters. Specifically, C-centred hexagold(I) clusters protected by chiral N-heterocyclic carbenes are etched with bisphosphine to yield C-centred pentagold(I) (CAuI5) clusters. The CAuI5 clusters exhibit an unusually large bathochromic shift in luminescence, which is reproduced theoretically. The etching mechanism is experimentally and theoretically suggested to be a tandem dissociation-association-elimination pathway. Furthermore, the vacant site of the central carbon of the CAuI5 cluster can accommodate AuCl, allowing for post-functionalisation of the C-centred gold(I) clusters.

Boosting oxygen reduction electrocatalytic performance of Cu-Nx by modulating electron structure via construction of Cu-Nx and Cu nanocluster coupling catalyst

The utilization of atom-dispersed Cu-Nx site catalysts holds significant promise as a replacement for commercial Pt/C catalyst in the context of oxygen reduction catalysts. However, practical application of these catalysts has been hindered by their insufficient catalytic activity. It is imperative to enhance the oxygen reduction reaction (ORR) catalytic activity of the Cu-Nx catalysts by manipulating electronic structure of the Cu-Nx site. This study presents the synthesis of a composite catalyst, formed by coupling Cu nanoclusters and Cu-Nx catalysts through pyrolysis of protein-Cu2+ gel followed by acid-leaching treatment. The resultant composite catalyst demonstrates superior ORR activity as compared to isolated Cu-Nx catalysts under alkaline conditions. Through density functional theory (DFT) calculations, the synergistic mechanism of the coupled Cu nanoclusters and Cu-Nx for ORR catalytic activity is elucidated. The proximity of the Cu nanoclusters (Cu4) to the central Cu atom of Cu-Nx (CuN4) in the composite catalyst causes a shift in the d-band center of the active Cu site towards the Fermi level. This shift strengthens the binding energy of O2 adsorption, reduces ORR overpotential, and combines with favorable electron transfer from Cu nanoclusters to Cu-Nx sites, thereby enhancing ORR activity. These findings contribute novel insights into the enhancement of ORR catalysis performance through the manipulation of electron structures via nano-sized metal clusters.

In-situ determination of micro-hardness in laser cladding of stellite using optical emission spectroscopy

Offline measurements in Laser Cladding (LC) processes, such as micro-hardness measurement, are destructive and time-consuming tests. Therefore, in-situ monitoring of clads parameters is of significant importance. In this study, we investigate the plasma plume emission produced during the LC process of Stellite 6 powder on a low-carbon steel substrate and its correlation with the micro-hardness of the clads over a wide range of LC parameters. It is demonstrated that a strong correlation between the spectral features in the UV region of 280–320 nm and micro-hardness exists, so that, the micro-hardness of samples can be determined by the total intensity of light in this range, within an average tolerance of 10 %. An exponential relation between hardness and UV radiation is empirically obtained that works very well for a wide range of dilutions, from 20 % to 70 %. It means that the UV spectra even determine the micro-hardness of samples with dilutions above 60 %, where the process shifts towards laser powder welding. This radiation is suggested to originate from the collisions of electrons with nano-sized clusters, which are produced during the laser interaction with the melt pool. The produced nanoparticles are the source of UV radiation and scatters the driving laser light, at the same time, processes that qualitatively explain the exponential relationship between the hardness and the UV light intensity.

Desensitization of AA5083 alloy via pulsed laser irradiation and its microstructural mechanism

In the present work, a laser surface desensitization (LSD) method was carried out on sensitized AA5083 alloy with the underlying microstructural evolution examined. The enhanced corrosion resistance after LSD process was confirmed by nitric acid mass loss test (NAMLT), immersion test and electrochemical measurements, which is mainly ascribed to the modification of grain boundary chemistry. Accompanied with the dissolution of grain boundary β (Al3Mg2) phase during LSD process, the grain boundaries could be characterized by Mg segregation or nano-sized Mg-rich clusters, which may also be absent from chemical uniformity depending on grain boundary misorientation.

Stabilization of weakly associated water forms by the surface of compacted methylsilica and its composites with Betulin

A complex of physicochemical methods was used to study the morphology and structure of the surface of methylsilica AM-1. Hydration of methylsilica was carried out by mechanochemical activation in the presence of water. The structure of the hydrate layer was studied using low-temperature 1H NMR spectroscopy. It has been established that adsorbed water is present in the form of nanosized clusters with a radii R = 0.4–20 nm, some of which are in a strongly associated state (SAW), and the other in a weakly associated state (WAW). The properties of the weakly associated state of water are similar to the supercritical state, which exists at high temperatures and pressures in the form of nanosized surface clusters. A method has been developed for the formation of a hydrated composite system AM-1/Betulin, which provides it possible for a significant amount of weakly associated water forms to exist in the surface layer. The contact of composite particles with a liquid hydrophobic medium (modeling hydrophobic areas of the gastrointestinal mucosa) further increases the amount of WAW even more. The binding energy of water and the size of adsorbed water clusters depend on the method of hydration. In the case of soft hydration by shaking with water, large clusters of SAW are formed on the surface, localized on the molecules of adsorption-fixed Betulin. During hard hydration (grinding with water in a porcelain mortar), water penetrates into the gaps between hydrophobic particles of methylsilica or methylsilica with immobilized Betulin and forms clusters of WAW, the radii of which can be 0.4–8 nm. This type of interfacial water exists in a wide temperature range, its amount increases with increasing temperature. Thus, a new type of composites has been created, promising for use as antiviral and anticancer drugs.

Extending damage accumulation of commercial reactor irradiated 316 stainless steel with ion irradiation

Austenitic 316 stainless steel flux thimble tubes (FTTs) removed from a commercial pressurized water reactor (PWR) were re-irradiated using nickel ions to evolve the irradiated microstructure to higher damage levels than those achieved in reactor. The microstructures of the neutron-plus-ion irradiated samples were compared with those of neutron irradiated only samples at the same doses to evaluate the effectiveness of ion irradiation to extend the damage range and match that created in reactor. Ion irradiations effectively captured, both qualitatively and semi-quantitatively, the evolution of dislocation loops, nanocavities, nanocluster size and density, and radiation-induced segregation (RIS) with dose. Only Ni-Si clusters were observed in ion irradiated FTT samples while Ni-Si-Mn clusters that were frequently observed in reactor irradiated samples above ∼41 dpa were absent in ion irradiated samples probably due to ballistic mixing at the high ion irradiation damage rate. Two samples were ion irradiated to ∼160 dpa to predict the irradiated microstructure that may develop due to an increase of the damage accumulation by extending a PWR life from 40 years to 60 years. The extended ion irradiation results indicated that significant microstructure changes were unlikely to occur even to very high doses near common PWR relevant temperature conditions. Overall, the microstructure resulting from ion irradiation following neutron irradiation matched that of neutron to the same dose reasonably well in most cases.

Metallic Nanoclusters for Electrochemical Water Splitting

AbstractElectrocatalytic water splitting is regarded as one of the most promising strategies for producing clean and sustainable energy sources (H2 and O2) in cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER), respectively. Currently, transition metal nanoparticles (NPs) such as commercial Pt/C, IrO2, and RuO2 are still popular catalysts for industrial‐level HER and OER processes. However, both the high cost and low atomic utilization of NPs can not satisfy the requirements of atomic economy and green chemistry. Compared with NPs, metallic nanoclusters (NCs), which have higher atom utilization and optimized electronic structure than NPs, show unique activities for water splitting. In this review, the recently reported advanced design strategies for preparing various NCs are discussed in detail. The methods to control the particle size, coordinated environment, and morphology of NCs are also summarized. The electrochemical activity and stability of NCs can be influenced by the synergistic effect between NCs and supporting materials, which is also mentioned. Then, the recently reported state‐of‐art‐catalysts for both HER and OER along with the detailed catalytic mechanism are described to show the advanced design principles. Finally, the future perspectives and some remaining challenges are also presented.

Study of Precipitates in Oxide Dispersion-Strengthened Steels by SANS, TEM, and APT.

In this work, the nanostructure of oxide dispersion-strengthened steels was studied by small-angle neutron scattering (SANS), transmission electron microscopy (TEM), and atom probe tomography (APT). The steels under study have different alloying systems differing in their contents of Cr, V, Ti, Al, and Zr. The methods of local analysis of TEM and APT revealed a significant number of nanosized oxide particles and clusters. Their sizes, number densities, and compositions were determined. A calculation of hardness from SANS data collected without an external magnetic field, or under a 1.1 T field, showed good agreement with the microhardness of the materials. The importance of taking into account two types of inclusions (oxides and clusters) and both nuclear and magnetic scattering was shown by the analysis of the scattering data.

Photocatalytic driven ‘self-cleaning’ IPN membranes infused with a ‘host-guest’ pair consisting of metal-organic framework encapsulated anionic ‘nano-clusters’ for water remediation

Traditional water treatment membranes frequently encounter challenges in attaining an ideal equilibrium between permeability and selectivity. The performance of membranes is further hampered by hydrophobicity, scalability, and fouling problems, as well as excessive energy consumption. Hence, the current research is dedicated to the development of highly effective antifouling membranes, aiming for a significant balance between water permeance and separation efficiency, and featuring exceptional photocatalytic self-cleaning properties to ensure the sustainable reuse of membranes. In this study, a unique nanocomposite-based membrane is designed containing metal-organic frameworks (MOFs) MIL-101 (Fe) encapsulated copper-containing polyoxometalate (Cu-POM) incorporated into an interpenetrating polymer networks (IPNs) membrane. POMs are highly electronegative, oxo-enriched nanosized metal-oxygen cluster species and when composited with MOF yields POMOF which can help in the removal of pollutants from water through electrostatic site-specific binding. The IPN membrane designed by polymerizing aniline in the presence of polyvinylidene fluoride (PVDF) offers tunable pores of the membrane. The infusion of POMOF imparts a strong negative charge to the membrane surface, improving membrane hydrophilicity. This enhances pollutant removal through the Donnan exclusion principle and adds anti-fouling properties. Furthermore, the reduced pore size achieved by the IPN architecture in the POMOF@IPNs membrane effectively sieves out both cationic and anionic dyes, as well as pharmaceutical pollutants. Additionally, POMOF enhances the photocatalytic degradation of CR and MB dyes, coupled with essential self-cleaning attributes vital for separation processes. The IPNs structure, apart from housing POMOF, fortifies the membrane's mechanical strength with its distinctive network-like configuration. Furthermore, these advanced membranes showcase robust antibacterial and antiviral characteristics, while remaining non-cytotoxic to mammalian cells. Our findings indicate that the state-of-the-art POMOF@IPNs membrane is scalable and holds substantial promise for industrial wastewater treatment.

Mechanism of Ionomer Film Formation via Solution Drying.

Film formation via the drying of ionomer solutions is a crucial process that has a strong influence on the morphology and transport properties of polymer electrolyte membranes and thin films. However, the microscopic mechanism of this process remains unclear. Here, we elucidate this mechanism using a coarse-grained model based on all-atom molecular dynamics that accurately reproduces small-angle X-ray scattering spectra. In dilute ionomer solutions, ionomers form rod-like bundles with diameters of 1.5-2 nm. As the water solvent evaporates, these bundles gradually aggregate and connect to each other, while maintaining their diameter. Finally, the remaining water forms nanosized clusters surrounded by the surfaces of the bundles with hydrophilic sulfonate groups.

Calculations of the effect of catalyst size and structure on the electrocatalytic reduction of CO2 on Cu nanoclusters.

The structure and catalytic properties of Cu nanoclusters of sizes between 55 and 147 atoms were examined to understand if small Cu clusters could provide enhancement over traditional catalysts for the electrocatalysis of CO2 to CO and carbon-based fuels, such as CH4 and CH3OH, compared to bulk Cu surfaces and large Cu nanoparticles. Clusters studied included Cu55, Cu78, Cu101, Cu124, and Cu147, the structures of which were determined using global optimisation. The majority of Cu clusters examined were icosahedral, including the perfect closed-shell, partial-shell, elongated and distorted icosahedral clusters. Free energy diagrams for the reduction of CO2 showed the potential required for the formation of CO is notably smaller for all cluster sizes considered, relative to Cu(111). Less variation is observed for the limiting potential for the formation of CH4 and CH3OH. However, it was found that clusters that are either a distorted motif or contain vacancy defects yielded the best activity and provide an interesting synthesis target for future experiments.

Tandem templating strategies facilitate the assembly of calix[8]arene-supported Ln18 clusters.

Calix[n]arenes offer ideal chemical functionality through the polyphenolic lower rim to construct nano-sized coordination clusters with lanthanide (Ln) metal ions (e.g., NdIII10, GdIII8). However, the number of metal centers they can accommodate is still limited compared to that achievable with smaller ligands (e.g., GdIII140, GdIII104). Here, we exploit a combination of the "anion template strategy" and "templating ligands" to synthesise three highly symmetric (D3h, trigonal planar) LnIII18 (Ln = La, Nd, and Gd) systems, representing the largest calix[n]arene-based coordination clusters yet. The LnIII18 fragment is templated by a chloride anion located at the center of the cluster, wherefrom twelve μ3-OH- ligands bind 'internally' to the eighteen LnIII ions. 'Externally' the metallic skeleton is connected by p-tert-butylcalix[8]arene, oxo, chloro and carbonate ligands. The crystal packing in the lattice reveals large cylindrical channels of ∼26 Å in diameter, whose pore volume corresponds to ∼50% of the unit cell volume (using a 1.2 Å spherical probe radius). Magnetic measurements reveal the predominance of weak antiferromagnetic exchange in the Gd analog. Heat capacity data of GdIII18 reveal a high magnetic entropy with -ΔSm = 23.7 J K-1 kg-1, indicating potential for engineering magnetic refrigerant materials with calix[8]arenes.