Heterometallic AuI 6 AgI 6 Macrocyclic Cluster Templated by a Supramolecular Melamine Dimer

The application of supramolecular templates in aligning atomically precise heterometal arrays is important for pursuing functional materials. Herein, we report that a bilayered supramolecular tri-deprotonated melamine dimer functions as an effective template in the construction of a heterometallic gold(I)-silver(I) macrocyclic cluster [μ6 -(C3 N6 H3 )3- ]2 -AuI 6 AgI 6 . X-ray single crystal structural analysis showed that a crown-like AuI 6 AgI 6 macrocycle is aligned around two parallelly stacked μ6 -(C3 N6 H3 )3- moieties hold together with π-π interactions. Theoretical calculations revealed that the [μ6 -(C3 N6 H3 )3- ]2 motif dominantly contributes to the near-occupied orbitals in the electronic structure, which is closely related to its luminescence properties. This work demonstrates that the supramolecular templates containing multiple symmetric binding sites may present a facile approach in the construction of functional metal clusters.

Crystal structure of a water oxidation catalyst solvate with composition (NH4)2[FeIV(L-6H)]·3CH3COOH (L = clathrochelate ligand)

The synthetic availability of mol-ecular water oxidation catalysts containing high-valent ions of 3d metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of di-ammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodeca-aza-tetra-cyclo-[8.8.4.13,17.18,12]tetra-cosane-5,6,14,15,20,21-hexa-onato}ferrate(IV) acetic acid tris-olvate, (NH4)2[FeIV(C12H12N12O6)]·3CH3COOH or (NH4)2[FeIV(L-6H)]·3CH3COOH is reported. The FeIV ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping tri-aza-cyclo-hexane fragments making three five- and six six-membered alternating chelate rings with the central FeIV ion. The local coord-ination environment of FeIV is formed by six deprotonated hydrazide nitro-gen atoms, which stabilize the unusual oxidation state. The FeIV ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter e) of the space group C2/c. Its coordination geometry is inter-mediate between a trigonal prism (distortion angle φ = 0°) and an anti-prism (φ = 60°) with φ = 31.1°. The Fe-N bond lengths lie in the range 1.9376 (13)-1.9617 (13) Å, as expected for tetra-valent iron. Structure analysis revealed that three acetic acid mol-ecules additionally co-crystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid mol-ecules are inter-connected by an intricate system of hydrogen bonds, mainly via the oxamide oxygen atoms acting as acceptors.

A thin-film polymer heating element with a continuous silver nanowires network embedded inside

This study presents a method for fabricating a film-based heating element using a polymer material with an array of intersecting conductive elements embedded within it. Track-etched membranes (TM) with a thickness of 10μm were used as the template, and their pores were filled with metal, forming a three-dimensional grid. Due to the unique manufacturing process of TM, the pores inside intersect with each other, allowing for contacts between individual nanowires (NWs) when filled with metal. Experimental results demonstrated that filling the TM pores with silver allows for heating temperatures up to 78 degrees without deformation or damage to the heating element. The resulting flexible heating element can be utilized in medical devices for heating purposes or as a thermal barrier coating.

Direct Synthesis of ABCD-Porphyrin Platinum(II) Complexes via Dehydrative Aromatization

Since the development of the first method for porphyrin synthesis by Rothemund in 1935, porphyrin derivatives have been widely investigated and have played an essential role in chemical sciences. Most synthetic routes of porphyrins involve oxidative aromatization. Herein, we present a synthetic method to produce ABCD-porphyrins, including chiral ones, through a one-pot reaction involving "coordination, cyclization, and dehydrative aromatization" using a mono-dipyrrinatoPt(II)Cl(COE) (COE=cyclooctene) complex as a platinum template.

Controllable Fabrication of Highly Uniform Sub-10 nm Nanoparticles from Spontaneous Confined Nanoemulsification

Sub-10 nm nanoparticles are known to exhibit extraordinary size-dependent properties for wide applications. Many approaches have been developed for synthesizing sub-10 nm inorganic nanoparticles, but the fabrication of sub-10 nm polymeric nanoparticles is still challenging. Here, a scalable, spontaneous confined nanoemulsification strategy that produces uniform sub-10 nm nanodroplets for template synthesis of sub-10 nm polymeric nanoparticles is proposed. This strategy introduces a high-concentration interfacial reaction to create overpopulated surfactants that are insoluble at the droplet surface. These overpopulated surfactants act as barriers, resulting in highly accumulated surfactants inside the droplet via a confined reaction. These surfactants exhibit significantly changed packing geometry, solubility, and interfacial activity to enhance the molecular-level impact on interfacial instability for creating sub-10 nm nanoemulsions via self-burst nanoemulsification. Using the nanodroplets as templates, the fabrication of uniform sub-10 nm polymeric nanoparticles, as small as 3.5 nm, made from biocompatible polymers and capable of efficient drug encapsulation is demonstrated. This work opens up brand-new opportunities to easily create sub-10 nm nanoemulsions and advanced ultrasmall functional nanoparticles.

Molecular and Electronic Structures of Macrocyclic Compounds Formed at Template Synthesis in the M(II)-Thiocarbohydrazide-Diacetyl Triple Systems: A Quantum-Chemical Analysis by DFT Methods

Using density functional theory (DFT) B3PW91/TZVP, M06/TZVP, and OPBE/TZVP chemistry models and the Gaussian09 program, a quantum-chemical calculation of geometric and thermodynamic parameters of Ni(II), Cu(II), and Zn(II) macrotetracyclic chelates, with (NNNN)-coordination of ligand donor centers arising during template synthesis between the indicated ions of 3d elements, thiocarbohydrazide H₂N-HN-C(=S)-NH-NH₂ and diacetyl Me-C(=O)-C(=O)-Me, in gelatin-immobilized matrix implants was performed. The key bond lengths and bond angles in these coordination compounds are provided, and it is noted that in all these complexes the MN₄ chelate sites, the grouping of N₄ atoms bonded to the M atom, and the five-membered and six-membered metal chelate rings are practically coplanar. NBO analysis of these compounds was carried out, on the basis of which it was shown that all these complexes, in full accordance with theoretical expectations, are low-spin complexes. The standard thermodynamic characteristics of the template reactions for the formation of the above complexes are also presented. Good agreement between the data obtained using the above DFT levels is noted.

Eco-Friendly Electroless Template Synthesis of Cu-Based Composite Track-Etched Membranes for Sorption Removal of Lead(II) Ions

This paper reports the synthesis of composite track-etched membranes (TeMs) modified with electrolessly deposited copper microtubules using copper deposition baths based on environmentally friendly and non-toxic reducing agents (ascorbic acid (Asc), glyoxylic acid (Gly), and dimethylamine borane (DMAB)), and comparative testing of their lead(II) ion removal capacity via batch adsorption experiments. The structure and composition of the composites were investigated by X-ray diffraction technique and scanning electron and atomic force microscopies. The optimal conditions for copper electroless plating were determined. The adsorption kinetics followed a pseudo-second-order kinetic model, which indicates that adsorption is controlled by the chemisorption process. A comparative study was conducted on the applicability of the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption models to define the equilibrium isotherms and the isotherm constants for the prepared composite TeMs. Based on the regression coefficients R², it has been shown that the Freundlich model better describes the experimental data of the composite TeMs on the adsorption of lead(II) ions.

Dual-Silica Template-Mediated Synthesis of Nitrogen-Doped Mesoporous Carbon Nanotubes for Supercapacitor Applications

1D carbon nanotubes have been widely applied in many fields, such as catalysis, sensing and energy storage. However, the long tunnel-like pores and relatively low specific surface area of carbon nanotubes often restrict their performance in certain applications. Herein, a dual-silica template-mediated method to prepare nitrogen-doped mesoporous carbon nanotubes (NMCTs) through co-depositing polydopamine (both carbon and nitrogen precursors) and silica nanoparticles (the porogen for mesopore formation) on a silica nanowire template is proposed. The obtained NMCTs have a hierarchical pore structure of large open mesopores and tubular macropores, a high specific surface area (1037 m² g^-1 ), and homogeneous nitrogen doping. The NMCT-45 (prepared at an interval time of 45 min) shows excellent performance in supercapacitor applications with a high capacitance (373.6 F g^-1 at 1.0 A g-¹ ), excellent rate capability, high energy density (11.6 W h kg^-1 at a power density of 313 W kg^-1 ), and outstanding cycling stability (98.2% capacity retention after 10 000 cycles at 10 A g^-1 ). Owing to the unique tubular morphology, hierarchical porosity and homogeneous N-doping, the NMCT also has tremendous potential in electrochemical catalysis and sensing applications.

Template-Directed Incorporation of Functional Molecules into DNA

We report a versatile method for the incorporation of functional molecules into oligonucleotides carrying reactive groups by using a template-directed postsynthetic approach in the solution phase. For this purpose, we prepared oligonucleotides carrying an amino group on the backbone by using an acylic threoninol scaffold. The resulting oligonucleotides could be used to introduce almost any molecule carrying aldehyde, which can be, among other things, a metal-binding ligand or a fluorophore. In our study, we incorporated aldehyde-bearing phenanthroline, a metal-binding ligand, into oligonucleotides by template-directed reversible conjugation. We observed that the use of an abasic sugar site instead of a natural nucleobase in the template strand increased the yield of conjugation and induced selective incorporation of the phenanthroline. This method could lead progress in the development of probes for the recognition of abasic regions in duplex DNA. Moreover, template-directed formation of metal ligand-oligonucleotide conjugates might have potential applications in hybrid biocatalysis for enantioselective transformations.

Scalable and Robust Hollow Nanopillar Electrode for Enhanced Intracellular Action Potential Recording

Electrophysiology is a unique biomarker of the electrogenic cells that can perform a disease investigation or drug assessment. In the recent decade, vertical nanoelectrode arrays can successfully achieve a high-quality intracellular electrophysiological study in electrogenic cells and their networks. However, a high success rate and high-quality and long-term intracellular recording using low-cost nanostructures is still a considerable challenge. Herein, we develop a scalable and robust hollow nanopillar electrode to achieve enhanced intracellular recording of cardiomyocytes. The template-based synthesis of vertical hollow nanopillars is compatible with large-scale and efficient microfabrication processes and is convenient to regulate the geometry of hollow nanopillars. Compared with the conventional same-size planar electrode, the regulating height of a hollow nanopillar can achieve high-quality and prolonged intracellular recordings, which can improve the cell-electrode interface for tight coupling and effective electroporation. It is demonstrated that the geometry regulation of a nanostructure is a powerful strategy to enhance intracellular recording.

Calix[6]arene-Based [3]Rotaxanes as Prototypes for the Template Synthesis of Molecular Capsules

In this work, the ability of several bis-viologen axles to thread a series of heteroditopic tris(N-phenylureido)calix[6]arene wheels to give interwoven supramolecular complexes to the [3]pseudorotaxane type was studied. The unidirectionality of the threading process inside these nonsymmetric wheels allows the formation of highly preorganised [3]pseudorotaxane and [3]rotaxane species in which the macrocycles phenylureido moieties, functionalised with either ester, carboxylic, or hydroxymethyl groups, are facing each other. As verified by NMR and semiempirical computational studies, these latter compounds possess the correct spatial arrangement of their subcomponents, which could lead, in principle, upon proper bridging reaction, to the realisation of upper-to-upper molecular capsules that are based on calix[6]arene derivatives.

In situ turning defects of exfoliated Ti(3)C(2) MXene into Fenton-like catalytic active sites

Controllable in situ formation of nanoclusters with discrete active sites is highly desirable in heterogeneous catalysis. Herein, a titanium oxide-based Fenton-like catalyst is constructed using exfoliated Ti₃C₂ MXene as a template. Theoretical calculations reveal that a redox reaction between the surface Ti-deficit vacancies of the exfoliated Ti₃C₂ MXene and H₂O₂ molecules facilitates the in situ conversion of surface defects into titanium oxide nanoclusters anchoring on amorphous carbon (TiO_x@C). The presence of mixed-valence Ti^δ+ (δ = 0, 2, 3, and 4) within TiO_x@C is confirmed by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) characterizations. The abundant surface defects within TiO_x@C effectively promote the generation of reactive oxygen species (ROS) leading to superior and stable Fenton-like catalytic degradation of atrazine, a typical agricultural herbicide. Such an in situ construction of Fenton-like catalysts through defect engineering also applies to other MXene family materials, such as V₂C and Nb₂C.

SnS2 Nanosheets as a Template for 2D SnO2 Sensitive Material: Nanostructure and Surface Composition Effects

Two-dimensional nanosheets of semiconductor metal oxides are considered as promising for use in gas sensors, because of the combination of a large surface-area, high thermal stability and high sensitivity, due to the chemisorption mechanism of gas detection. In this work, 2D SnO₂ nanosheets were synthesized via the oxidation of template SnS₂ nanosheets obtained by surfactant-assisted one-pot solution synthesis. The 2D SnO₂ was characterized using transmission and scanning electron microscopy (TEM, SEM), X-ray diffraction (XRD), low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and IR spectroscopy. The sensor characteristics were studied when detecting model gases CO and NH₃ in dry (RH₂₅ = 0%) and humid (RH₂₅ = 30%) air. The combination of high specific-surface-area and increased surface acidity caused by the presence of residual sulfate anions provides a high 2D SnO₂ sensor's signal towards NH₃ at a low temperature of 200 °C in dry air, but at the same time causes an inversion of the sensor response when detecting NH₃ in a humid atmosphere. To reveal the processes responsible for sensor-response inversion, the interaction of 2D SnO₂ with ammonia was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in dry and humid air at temperatures corresponding to the maximum "positive" and maximum "negative" sensor response.

Noble-Metal-Based Hollow Mesoporous Nanoparticles: Synthesis Strategies and Applications

As second-generation mesoporous materials, mesoporous noble metals (NMs) are of significant interest for their wide applications in catalysis, sensing, bioimaging, and biotherapy owing to their structural and metallic features. The introduction of interior hollow cavity into NM-based mesoporous nanoparticles (MNs), which subtly integrate hierarchical hollow and mesoporous structure into one nanoparticle, produces a new type of hollow MNs (HMNs). Benefiting from their higher active surface, better electron/mass transfer, optimum electronic structure, and nanoconfinement space, NM-based HMNs exhibit their high efficiency in enhancing catalytic activity and stability and tuning catalytic selectivity. In this review, recent progress in the design, synthesis, and catalytic applications of NM-based HMNs is summarized, including the findings of the groups. Five main strategies for synthesizing NM-based HMNs, namely silica-assisted surfactant-templated nucleation, surfactant-templated sequential nucleation, soft "dual"-template, Kirkendall effect in synergistic template, and galvanic-replacement-assisted surfactant template, are described in detail. In addition, the applications in ethanol oxidation electrocatalysis and hydrogenation reactions are discussed to highlight the high activity, enhanced stability, and optimal selectivity of NM-based HMNs in (electro)catalysis. Finally, the further outlook that may lead the directions of synthesis and applications of NM-based HMNs is prospected.

Ghost-Template-Faceted Synthesis of Tunable Amorphous Hollow Silica Nanostructures and Their Ordered Mesoscale Assembly

Despite the enormous applications of and fundamental scientific interest in amorphous hollow-silica nanostructures (h-SiNSs), their synthesis in crystal-like nonspherical polygonal architectures is challenging. Herein, we present a facile one-shot synthetic procedure for various unconventional h-SiNSs with controllable surface curvatures (concave, convex, or angular), symmetries (spherical, polygonal, or Janus), and interior architectures (open or closed walls) by the addition of a metal salt and implementing kinetic handles of silica precursor (silanes/ammonia) concentrations and reverse-micellar volume. During the silica growth, we identified the key role of transiently in situ crystallized metal coordination complexes as a nanopolyhedral "ghost template", which provides facet-selective interactions with amino-silica monomers and guides the differential silica growth that produces different h-SiNSs. Additionally, crystal-like well-defined polygonal h-SiNSs with flat surfaces, assembled as highly ordered close-packed octahedral mesoscale materials (ca. 3 μm) where h-SiNSs with different nanoarchitectures act as building units (ca. 150 nm) to construct customizable cavities and nanospaces, differ from conventionally assembled materials.

Track-Etch Membranes as Tools for Template Synthesis of Highly Sensitive Pressure Sensors

Flexible pressure sensors with high sensitivity are highly desired in wearable electronics and human-machine interaction. Introducing the surface microstructures to the capacitive-type sensors can improve sensitivity and reduce response time. However, conventional techniques for the fabrication of highly sensitive and large-area pressure sensors still remain challenging. Here, a template synthesis approach is reported for fabrication of a large-area and low-cost ionic micropillar array templated from track-etch membranes. The pressure sensors based on the ionic micropillars gel dielectric layers exhibit a low limit of detection (∼0.5 Pa) and high sensitivity (14.83 kPa^-1) in the low-pressure regime (0-5 kPa) and linear sensitivity (1.96 kPa^-1) over a wide pressure range of 24-230 kPa. The versatility of the sensors is demonstrated in various human physiological signal detection scenarios and spatial pressure distribution. Furthermore, a real-time pressure mapping insole was fabricated on the basis of a large-area micropillared ionic gel dielectric layer combined with the screen-printing technique. The scalable and low-cost fabrication of pressure sensors with micropillars templated from a track-etch membrane provides new insights into the future development of health monitoring and human-machine interaction.

Highly Elastic Interconnected Porous Hydrogels through Self-Assembled Templating for Solar Water Purification

Interfacial evaporation using porous hydrogels has demonstrated highly effective solar evaporation performance under natural sunlight to ensure an affordable clean water supply. However, it remains challenging to realize scalable and ready-to-use hydrogel materials with durable mechanical properties. Here, self-assembled templating (SAT) is developed as a simple yet effective method to fabricate large-scale elastic hydrogel evaporators with excellent desalination performance. The highly interconnected porous structure of the hydrogels with low tortuosity and tunable pore size enables high level of tunability on the water transport rate. With superior elasticity, the porous hydrogels are easy to process with a rapid shape recovery after being rolled, folded, and twisted over hundred times, and exhibit highly effective and stable evaporation with an evaporation rate of ≈2.8 kg m^-2  h^-1 and ≈90 % solar-to-vapor efficiency. It is anticipated that this SAT strategy, without the typical need for freeze-drying, will accelerate the industrialization of hydrogel solar evaporators for practical applications.

Features of Fabrication of Titanium Dioxide Based Coatings for Non-Lithographic Template Electrochemical Synthesis of Micron Metal Particle Arrays

This work is devoted to the development of non-lithographic template methods of synthesis. These methods have a significant advantage in terms of structure formation: there is no need to design and produce masks, which greatly simplifies the process, and more of them can work with nonplanar substrates. The purpose of this study was to reveal the conditions for the synthesis of titanium dioxide xerogel films of different topologies as well as to develop a technique for non-lithographic template electrochemical synthesis of micron metal particles arrays and to study the structure of the resulting coatings. The films were deposited on the surface of substrates via dip coating. Specific topology of the films was achieved by template sol-gel synthesis. Their structures were analyzed by SEM and XRD. Template synthesis of metal micro particles were realized by pulsed electrochemical deposition of metals into the perforations of xerogel films. Obtained materials were analyzed by SEM and XRD; the element distribution on the surface was determined by the EDS detector of SEM. Based on the analysis results, we suggest the mechanisms of formation of the xerogel topology and proved the efficiency of pulsed electrodeposition for template synthesis of micron particles arrays.

Polyelectrolyte/Gold Nanoparticle Nanotubes Incorporating Doxorubicin-Loaded Liposomes

Anticancer agent doxorubicin-loaded liposomes (DoxLs) were drawn spontaneously into nanotubes comprising multilayers of polyelectrolytes and gold nanoparticles (PAuNTs). We describe a unique structure of PAuNTs incorporating DoxLs (DoxL-PAuNT). The number of DoxLs adsorbed on the tube interior surface was ascertained as 2.4×10³ . Heating stimuli engendered gel-liquid crystal phase transition of DoxL in the capillary, subsequently inducing efficient release of Dox without structural changes of the tubule or liposome. Furthermore, antitumor activity of the DoxL-PAuNTs on cancer cells was elucidated.

Synthesis and Characterization of Titanium Dioxide Hollow Nanofiber for Photocatalytic Degradation of Methylene Blue Dye

Environmental crisis and water contamination have led to worldwide exploration for advanced technologies for wastewater treatment, and one of them is photocatalytic degradation. A one-dimensional hollow nanofiber with enhanced photocatalytic properties is considered a promising material to be applied in the field. Therefore, we synthesized titanium dioxide hollow nanofibers (THNF) with extended surface area, light-harvesting properties and an anatase–rutile heterojunction via a template synthesis method and followed by a calcination process. The effect of calcination temperature on the formation and properties of THNF were determined and the possible mechanism of THNF formation was proposed. THNF nanofibers produced at 600 °C consisted of a mixture of 24.2% anatase and 75.8% rutile, with a specific surface area of 81.2776 m²/g. The hollow nanofibers also outperformed the other catalysts in terms of photocatalytic degradation of MB dye, at 85.5%. The optimum catalyst loading, dye concentration, pH, and H₂O₂ concentration were determined at 0.75 g/L, 10 ppm, pH 11, and 10 mM, respectively. The highest degradation of methylene blue dye achieved was 95.2% after 4 h of UV irradiation.

Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane

High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of ≥37% leads to a reversal magnetization state, in which a "curling"-type model of nanowire behavior is realized.

Dramatic Effect of A Ring Size of Alicyclic α-Dioximate Ligand Synthons on Kinetics of the Template Synthesis and of the Acidic Decomposition of the Methylboron-Capped Iron(II) Clathrochelates

Kinetics and thermodynamics of the template synthesis and of the acidic decomposition of the methylboron-capped iron(II) tris-1,2-dioximates—the clathrochelate derivatives of six (nioxime)- and eight (octoxime)-membered alicyclic ligand synthons—were compared. In the case of a macrobicyclic iron(II) tris-nioximate, the plausible pathway of its formation contains a rate-determining stage and includes a reversible formation of an almost trigonal-antiprismatic (TAP) protonated tris-complex, followed by its monodeprotonation and addition of CH₃B(OH)₂. Thus, the formed TAP intermediate undergoes a multistep rate-determining stage of double cyclization with the elimination of two water molecules accompanied by a structural rearrangement, thus giving an almost trigonal-prismatic (TP) iron(FII) semiclathrochelate. It easily undergoes a cross-linking with CH₃B(OH)₂, resulting in the elimination of H⁺ ion and in the formation of a macrobicyclic structure. In contrast, the analogous scheme for its macrobicyclic tris-octoximate analog was found to contain up to three initial stages affecting the overall synthesis reaction rate. The rates of acidic decomposition of the above clathrochelates were found to be also affected by the nature of their ribbed substituents. Therefore, the single crystal XRD experiments were performed in order to explain these results. The difference in the kinetic schemes of a formation of the boron-capped iron(II) tris-nioximates and tris-octoximates is explained by necessity of the substantial changes in a geometry of the latter ligand synthon, caused by its coordination to the iron(II) ion, due to both the higher distortion of the FeN₆-coordination polyhedra, and the intramolecular sterical clashes in the molecules of the macrobicyclic iron(II) tris-octoximates.

Molten Salt Templated Synthesis of Covalent Isocyanurate Frameworks with Tunable Morphology and High CO2 Uptake Capacity

The use of reactive molten salts, i.e., ZnCl₂, as a soft template and a catalyst has been actively investigated in the preparation of covalent triazine frameworks (CTFs). Although the soft templating effect of the salt melt is more prominent at low temperatures, close to the melting point of ZnCl₂, leading to the formation of abundant micropores, a significant mesopore formation is observed that is due to the partial carbonization and other side reactions at higher temperatures (>400 °C). Evidently, high-temperature synthesis of CTFs in various eutectic salt mixtures of ZnCl₂ with alkali metal chloride salts also leads to mesopore formation. We reasoned that using the isocyanate moieties instead of cyano groups in the monomer, 1,4-phenylene isocyanate, could enable efficient interactions between carbonyl moieties and alkali metal ions to realize efficient salt templating to form covalent isocyanurate frameworks (CICFs). In this direction, the trimerization of 1,4-phenylene diisocyanate was carried out under ionothermal conditions at different reaction temperatures using ZnCl₂ (CICF) and the eutectic salt mixture of KCl/NaCl/ZnCl₂ (CICF-KCl/NaCl) as the reactive solvents. We observed notable differences in the morphologies of the two polymers, whereas CICF showed irregular-shaped micrometer-sized particles, the CICF-KCl/NaCl exhibited a filmlike morphology. Moreover, favorable ion-dipole interactions between alkali metal cations and oxygen atoms of the monomer facilitated two-dimensional growth and the formation of a purely microporous framework in the case of CICF-KCl/NaCl along with a near theoretical retention of the nitrogen content at 500 °C. The CICF-KCl/NaCl showed a BET surface area of 590 m² g^-1 along with a CO₂ uptake capacity of 5.9 mmol g^-1 at 273 K and 1.1 bar because of its high microporosity and nitrogen content. On the contrary, in the absence of alkali metal ions, CICF showed high mesopore content and a moderate CO₂ uptake capacity. This study underscores the importance of the strength of the interactions between the salts and the monomer in the ionothermal synthesis to control the morphology, porosity, and gas uptake properties of the porous organic polymers.

Zinc- and Cadmium meso-Aryl-Isoporphyrins: Non-Aromatic NIR Dyes with Distinct Conformational Features

A series of pyrrolyl and dipyrrinyl isoporphyrins carrying different phenyl and thienyl groups is reported. The compounds are obtained by a one-pot approach in the presence of a template reagent. Thienyl derivatives gave better yields, and were the only subclass to form with steric hindrance. The structural analyses carried out on compounds 1 and 14 revealed distinct conformational differences which are likely to result from an intramolecular NH… Cl hydrogen bridge of the pyrrolyl subclass. In addition, this hydrogen bridge strongly favors one of the two possible atropisomers. Hindered rotation of the meso-aryl groups is observed only in the cases of methylbenzothienyl derivatives 10 and 15 and leads to the observation of several diastereomers. NIR absorptions up to 923 nm are found throughout. Electrochemical investigations into the 1e- and 2e- reduced species unravel axial ligand exchange dynamics for the zinc isoporphyrin radical, and the probable formation of a zinc phlorinate.

A Single-Pot Template Reaction Towards a Manganese-Based T1 Contrast Agent

Manganese-based contrast agents (MnCAs) have emerged as suitable alternatives to gadolinium-based contrast agents (GdCAs). However, due to their kinetic lability and laborious synthetic procedures, only a few MnCAs have found clinical MRI application. In this work, we have employed a highly innovative single-pot template synthetic strategy to develop a MnCA, MnLMe , and studied the most important physicochemical properties in vitro. MnLMe displays optimized r1 relaxivities at both medium (20 and 64 MHz) and high magnetic fields (300 and 400 MHz) and an enhanced r1b =21.1 mM-1  s-1 (20 MHz, 298 K, pH 7.4) upon binding to BSA (Ka =4.2×103  M-1 ). In vivo studies show that MnLMe is cleared intact into the bladder through renal excretion and has a prolonged blood half-life compared to the commercial GdCA Magnevist. MnLMe shows great promise as a novel MRI contrast agent.

A Single-Pot Template Reaction Towards a Manganese-Based T1 Contrast Agent

Manganese-based contrast agents (MnCAs) have emerged as suitable alternatives to gadolinium-based contrast agents (GdCAs). However, due to their kinetic lability and laborious synthetic procedures, only a few MnCAs have found clinical MRI application. In this work, we have employed a highly innovative single-pot template synthetic strategy to develop a MnCA, MnLMe, and studied the most important physicochemical properties in vitro. MnLMe displays optimized r 1 relaxivities at both medium (20 and 64 MHz) and high magnetic fields (300 and 400 MHz) and an enhanced r 1 b=21.1 mM-1 s-1 (20 MHz, 298 K, pH 7.4) upon binding to BSA (K a=4.2×103 M-1). In vivo studies show that MnLMe is cleared intact into the bladder through renal excretion and has a prolonged blood half-life compared to the commercial GdCA Magnevist. MnLMe shows great promise as a novel MRI contrast agent.

MgO-Template Synthesis of Extremely High Capacity Hard Carbon for Na-Ion Battery

Extremely high capacity hard carbon for Na-ion battery, delivering 478 mAh g-1 , is successfully synthesized by heating a freeze-dried mixture of magnesium gluconate and glucose by a MgO-template technique. Influences of synthetic conditions and nano-structures on electrochemical Na storage properties in the hard carbon are systematically studied to maximize the reversible capacity. Nano-sized MgO particles are formed in a carbon matrix prepared by pre-treatment of the mixture at 600 °C. Through acid leaching of MgO and carbonization at 1500 °C, resultant hard carbon demonstrates an extraordinarily large reversible capacity of 478 mAh g-1 with a high Coulombic efficiency of 88 % at the first cycle.

Template-Mediated Control over Polymorphism in the Vapor-Assisted Formation of Zeolitic Imidazolate Framework Powders and Films

The landscape of possible polymorphs for some metal-organic frameworks (MOFs) can pose a challenge for controlling the outcome of their syntheses. Demonstrated here is the use of a template to control in the vapor-assisted formation of zeolitic imidazolate framework (ZIF) powders and thin films. Introducing a small amount of either ethanol or dimethylformamide vapor during the reaction between ZnO and 4,5-dichloroimidazole vapor results in the formation of the porous ZIF-71 phase, whereas other conditions lead to the formation of the dense ZIF-72 phase or amorphous materials. Time-resolved in situ small-angle X-ray scattering reveals that the porous phase is metastable and can be transformed into its dense polymorph. This transformation is avoided through the introduction of template vapor. The porosity of the resulting ZIF powders and films was studied by N₂ and Kr physisorption, as well as positron annihilation lifetime spectroscopy. The templating principle was demonstrated for other members of the ZIF family as well, including the ZIF-7 series, ZIF-8_Cl, and ZIF-8_Br.

Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High-Surface-Area Mesoporous CeO2 with Exceptional Redox Property

High-surface-area mesoporous CeO₂ (hsmCeO₂ ) was prepared by a facile organic-template-induced homogeneous precipitation process and showed excellent catalytic activity in imine synthesis in the absence of base from primary alcohols and amines in air atmosphere at low temperature. For comparison, ordinary CeO₂ and hsmCeO₂ after different thermal treatments were also investigated. XRD, N₂ physisorption, UV-Raman, H₂ temperature-programmed reduction, O₂ temperature-programmed desorption, EPR spectroscopy, and X-ray photoelectron spectroscopy were used to unravel the structural and redox properties. The hsmCeO₂ calcined at 400 °C shows the highest specific surface area (158 m²  g^-1 ), the highest fraction of surface coordinatively unsaturated Ce³⁺ ions (18.2 %), and the highest concentration of reactive oxygen vacancies (2.4×10¹⁵  spins g^-1 ). In the model reaction of oxidative coupling of benzyl alcohol and aniline, such an exceptional redox property of the hsmCeO₂ catalyst can boost benzylideneaniline formation (2.75 and 5.55 mmol  g ceria - 1  h^-1 based on >99 % yield at 60 and 80 °C, respectively) in air with no base additives. It can also work effectively at a temperature of 30 °C and in gram-scale synthesis. These are among the best results for all benchmark ceria catalysts in the literature. Moreover, the hsmCeO₂ catalyst shows a wide scope towards primary alcohols and amines with good to excellent yield of imines. The influence of reaction parameters, the reusability of the catalyst, and the reaction mechanism were investigated.

Kinetic and Isotherm Study of As(III) Removal from Aqueous Solution by PET Track-Etched Membranes Loaded with Copper Microtubes

This paper reports on the synthesis and structure elucidation of track-etched membranes (TeMs) with electrolessly deposited copper microtubes (prepared in etched-only and oxidized polyethylene terephthalate (PET) TeMs), as well as on the comparative testing of arsenic (III) ion removal capacities through bath adsorption experiments. The structure and composition of composites were investigated by X-ray diffraction technique and scanning electron and atomic force microscopies. It was determined that adsorption followed pseudo-second-order kinetics, and the adsorption rate constants were calculated. A comparative study of the applicability of the adsorption models of Langmuir, Freundlich, and Dubinin-Radushkevich was carried out in order to describe the experimental isotherms of the prepared composite TeMs. The constants and parameters of all of the above equations were determined. By comparing the regression coefficients R2, it was shown that the Freundlich model describes the experimental data on the adsorption of arsenic through the studied samples better than others. Free energy of As(III) adsorption on the samples was determined using the Dubinin-Radushkevich isotherm model and was found to be 17.2 and 31.6 kJ/mol for Cu/PET and Cu/Ox_PET samples, respectively. The high EDr value observed for the Cu/Ox_PET composite indicates that the interaction between the adsorbate and the composite is based on chemisorption.

[2]Catenane Synthesis via Covalent Templating

After earlier unsuccessful attempts, this work reports the application of covalent templating for the synthesis of mechanically interlocked molecules (MiMs) bearing no supramolecular recognition sites. Two linear strands were covalently connected in a perpendicular fashion by a central ketal linkage. After subsequent attachment of the first strand to a template via temporary benzylic linkages, the second was linked to the template in a backfolding macrocyclization. The resulting pseudo[1]rotaxane structure was successfully converted to a [2]catenane via a second macrocyclization and cleavage of the ketal and temporary linkages.

Removal of Heavy Metals from Wastewaters: A Challenge from Current Treatment Methods to Nanotechnology Applications

Removing heavy metals from wastewaters is a challenging process that requires constant attention and monitoring, as heavy metals are major wastewater pollutants that are not biodegradable and thus accumulate in the ecosystem. In addition, the persistent nature, toxicity and accumulation of heavy metal ions in the human body have become the driving force for searching new and more efficient water treatment technologies to reduce the concentration of heavy metal in waters. Because the conventional techniques will not be able to keep up with the growing demand for lower heavy metals levels in drinking water and wastewaters, it is becoming increasingly challenging to implement technologically advanced alternative water treatments. Nanotechnology offers a number of advantages compared to other methods. Nanomaterials are more efficient in terms of cost and volume, and many process mechanisms are better and faster at nanoscale. Although nanomaterials have already proved themselves in water technology, there are specific challenges related to their stability, toxicity and recovery, which led to innovations to counteract them. Taking into account the multidisciplinary research of water treatment for the removal of heavy metals, the present review provides an updated report on the main technologies and materials used for the removal of heavy metals with an emphasis on nanoscale materials and processes involved in the heavy metals removal and detection.

Covalent Post-Assembly Modification: A Synthetic Multipurpose Tool in Supramolecular Chemistry

The use of covalent post-assembly modification (PAM) in supramolecular chemistry has grown significantly in recent years, to the point where PAM is now a versatile synthesis tool for tuning, modulating, and expanding the functionality of self-assembled complexes and materials. PAM underpins supramolecular template-synthesis strategies, enables modular derivatization of supramolecular assemblies, permits the covalent 'locking' of unstable structures, and can trigger controlled structural transformations between different assembled morphologies. This Review discusses key examples of PAM spanning a range of material classes, including discrete supramolecular complexes, self-assembled soft nanostructures and hierarchically ordered polymeric and framework materials. As such, we hope to highlight how PAM has continued to evolve as a creative and functional addition to the synthetic chemist's toolbox for constructing bespoke self-assembled complexes and materials.

An Efficient and Stable MoS2 /Zn0.5 Cd0.5 S Nanocatalyst for Photocatalytic Hydrogen Evolution

Photocatalytic hydrogen evolution by water splitting is highly important for the application of hydrogen energy and the replacement of fossil fuel by solar energy, which needs the development of efficient catalysts with long-term catalytic stability under light irradiation in aqueous solution. Herein, Zn_0.5 Cd_0.5 S solid solution was synthesized by a metal-organic framework-templated strategy and then loaded with MoS₂ by a hydrothermal method to fabricate a MoS₂ /Zn_0.5 Cd_0.5 S heterojunction for photocatalytic hydrogen evolution. The composition of MoS₂ /Zn_0.5 Cd_0.5 S was fine-tuned to obtain the optimized 5 wt % MoS₂ /Zn_0.5 Cd_0.5 S heterojunction, which showed a superior hydrogen evolution rate of 23.80 mmol h^-1  g^-1 and steady photocatalytic stability over 25 h. The photocatalytic performance is due to the appropriate composition and the formation of an intimate interface between MoS₂ and Zn_0.5 Cd_0.5 S, which endows the photocatalyst with high light-harvesting ability and effective separation of photogenerated carriers.

Template Synthesis of Porous Ceria-Based Catalysts for Environmental Application

Porous oxide materials are widely used in environmental catalysis owing to their outstanding properties such as high specific surface area, enhanced mass transport and diffusion, and accessibility of active sites. Oxides of metals with variable oxidation state such as ceria and double oxides based on ceria also provide high oxygen storage capacity which is important in a huge number of oxidation processes. The outstanding progress in the development of hierarchically organized porous oxide catalysts relates to the use of template synthetic methods. Single and mixed oxides with enhanced porous structure can serve both as supports for the catalysts of different nature and active components for catalytic oxidation of volatile organic compounds, soot particles and other environmentally dangerous components of exhaust gases, in hydrocarbons reforming, water gas shift reaction and photocatalytic transformations. This review highlights the recent progress in synthetic strategies using different types of templates (artificial and biological, hard and soft), including combined ones, in the preparation of single and mixed oxide catalysts based on ceria, and provides examples of their application in the main areas of environmental catalysis.

Cu/CuO Composite Track-Etched Membranes for Catalytic Decomposition of Nitrophenols and Removal of As(III)

One of the promising applications of nanomaterials is to use them as catalysts and sorbents to remove toxic pollutants such as nitroaromatic compounds and heavy metal ions for environmental protection. This work reports the synthesis of Cu/CuO-deposited composite track-etched membranes through low-temperature annealing and their application in catalysis and sorption. The synthesized Cu/CuO/poly(ethylene terephthalate) (PET) composites presented efficient catalytic activity with high conversion yield in the reduction of nitro aryl compounds to their corresponding amino derivatives. It has been found that increasing the time of annealing raises the ratio of the copper(II) oxide (CuO) tenorite phase in the structure, which leads to a significant increase in the catalytic activity of the composites. The samples presented maximum catalytic activity after 5 h of annealing, where the ratio of CuO phase and the degree of crystallinity were 64.3% and 62.7%, respectively. The catalytic activity of pristine and annealed composites was tested in the reduction of 4-nitroaniline and was shown to remain practically unchanged for five consecutive test cycles. Composites annealed at 140 °C were also tested for their capacity to absorb arsenic(III) ions in cross-flow mode. It was observed that the sorption capacity of composite membranes increased by 48.7% compared to the pristine sample and reached its maximum after 10 h of annealing, then gradually decreased by 24% with further annealing.

Morphology and Microstructure Evolution of Gold Nanostructures in the Limited Volume Porous Matrices

The modern development of nanotechnology requires the discovery of simple approaches that ensure the controlled formation of functional nanostructures with a predetermined morphology. One of the simplest approaches is the self-assembly of nanostructures. The widespread implementation of self-assembly is limited by the complexity of controlled processes in a large volume where, due to the temperature, ion concentration, and other thermodynamics factors, local changes in diffusion-limited processes may occur, leading to unexpected nanostructure growth. The easiest ways to control the diffusion-limited processes are spatial limitation and localized growth of nanostructures in a porous matrix. In this paper, we propose to apply the method of controlled self-assembly of gold nanostructures in a limited pore volume of a silicon oxide matrix with submicron pore sizes. A detailed study of achieved gold nanostructures’ morphology, microstructure, and surface composition at different formation stages is carried out to understand the peculiarities of realized nanostructures. Based on the obtained results, a mechanism for the growth of gold nanostructures in a limited volume, which can be used for the controlled formation of nanostructures with a predetermined geometry and composition, has been proposed. The results observed in the present study can be useful for the design of plasmonic-active surfaces for surface-enhanced Raman spectroscopy-based detection of ultra-low concentration of different chemical or biological analytes, where the size of the localized gold nanostructures is comparable with the spot area of the focused laser beam.

Lanthanide-Containing Rotaxanes, Catenanes, and Knots

The valuable luminescence, magnetic, and catalytic properties of lanthanide cations are beginning to be exploited in conjunction with structurally exotic mechanically interlocked molecules (MIMs) such as rotaxanes, catenanes and knots. This Minireview provides an account of this rapidly developing research area commencing with the use of lanthanides in extended MIM-containing frameworks. Then, attention turns to discrete lanthanide-containing pseudorotaxanes, followed by fully interlocked rotaxanes, catenanes and knots - where lanthanides have not only been incorporated into MIM architectures but have also been used to template formation of the interlocked structure. Particular focus is paid to examples where the lanthanide MIMs have been put to useful applications, in what is still a relatively youthful avenue of research in both lanthanide coordination chemistry and the chemistry of mechanically interlocked molecules.

Dual Metastability in Electroless Plating: Complex Inertness Enabling the Deposition of Composition-Tunable Platinum Copper Alloy Nanostructures

Autocatalytic deposition represents a facile, versatile, and scalable wet-chemical tool for nanofabrication. However, the intricate component interplay in plating baths containing multiple metal species impedes alloy deposition. We resolved this challenge in the bimetallic copper-platinum system by exploiting the kinetic stability of platinum complexes, which allows adjusting their ligand sphere and thus reactivity independently from the present copper ions in a preceding, thermally activated ligand exchange step. By using metastable PtIV precursors of varying degrees of complexation, copper-platinum alloys of adjustable atomic ratio were plated from solutions of identical composition and concentration, but differing local coordination environment. Due to its excellent conformity and nanoscale homogeneity, the reaction is compatible with ambitious 3D substrate morphologies, as demonstrated in the template-assisted fabrication of nanotubes with high aspect ratio. The ability to generate additional synthetic degrees of freedom by decoupling the metal complex speciation from the solution composition is of large interest for redox-chemical synthesis techniques, such as electrodeposition or nanoparticle colloid production.

Rational Design of Hierarchical, Porous, Co-Supported, N-Doped Carbon Architectures as Electrocatalyst for Oxygen Reduction

Developing highly active nonprecious-metal catalysts for the oxygen reduction reaction (ORR) is of great significance for reducing the cost of fuel cells. 3D-ordered porous structures could substantially improve the performance of the catalysts because of their excellent mass-diffusion properties and high specific surface areas. Herein, ordered porous ZIF-67 was prepared by forced molding of a polystyrene template, and Co-supported, N-doped, 3D-ordered porous carbon (Co-NOPC) was obtained after further carbonization. Co-NOPC exhibited excellent performance for the ORR in an alkaline medium with a half-wave potential of 0.86 V vs. reversible hydrogen electrode (RHE), which is higher than that of the state-of-the-art Pt/C (0.85 V vs. RHE). Moreover, the substantially improved catalytic performance of Co-NOPC compared with Co-supported, N-doped carbon revealed the key role of its hierarchical porosity in boosting the ORR. Co-NOPC also exhibited a close-to-ideal four-electron transfer path, long-term durability, and resistance to methanol penetration, which make it promising for large-scale application.

Hierarchical Hollow-Nanocube Ni-Co Skeleton@MoO3 /MoS2 Hybrids for Improved-Performance Lithium-Ion Batteries

Improving the performance of anode materials for lithium-ion batteries (LIBs) is a hotly debated topic. Herein, hollow Ni-Co skeleton@MoS₂ /MoO₃ nanocubes (NCM-NCs), with an average size of about 193 nm, have been synthesized through a facile hydrothermal reaction. Specifically, MoO₃ /MoS₂ composites are grown on Ni-Co skeletons derived from nickel-cobalt Prussian blue analogue nanocubes (Ni-Co PBAs). The Ni-Co PBAs were synthesized through a precipitation method and utilized as self-templates that provided a larger specific surface area for the adhesion of MoO₃ /MoS₂ composites. According to Raman spectroscopy results, as-obtained defect-rich MoS₂ is confirmed to be a metallic 1T-phase MoS₂ . Furthermore, the average particle size of Ni-Co PBAs (≈43 nm) is only about one-tenth of the previously reported particle size (≈400 nm). If assessed as anodes of LIBs, the hollow NCM-NC hybrids deliver an excellent rate performance and superior cycling performance (with an initial discharge capacity of 1526.3 mAh g^-1 and up to 1720.6 mAh g^-1 after 317 cycles under a current density of 0.2 A g^-1 ). Meanwhile, ultralong cycling life is retained, even at high current densities (776.6 mAh g^-1 at 2 A g^-1 after 700 cycles and 584.8 mAh g^-1 at 5 A g^-1 after 800 cycles). Moreover, at a rate of 1 A g^-1 , the average specific capacity is maintained at 661 mAh g^-1 . Thus, the hierarchical hollow NCM-NC hybrids with excellent electrochemical performance are a promising anode material for LIBs.

Solid-State Nonlinear Optical Properties of Mononuclear Copper(II) Complexes with Chiral Tridentate and Tetradentate Schiff Base Ligands

Salen-type metal complexes have been actively studied for their nonlinear optical (NLO) properties, and push-pull compounds with charge asymmetry generated by electron releasing and withdrawing groups have shown promising results. As a continuation of our research in this field and aiming at solid-state features, herein we report on the synthesis of mononuclear copper(II) derivatives bearing either tridentate N₂O Schiff bases L^(a−c)− and pyridine as the forth ancillary ligand, [Cu(L^a−c)(py)](ClO₄) (1a–c), or unsymmetrically-substituted push-pull tetradentate N₂O₂ Schiff base ligands, [Cu(5-A-5′-D-saldpen/chxn)] (2a–c), both derived from 5-substituted salicylaldehydes (sal) and the diamines (1R,2R)-1,2-diphenylethanediamine (dpen) and (1S,2S)-1,2-diaminocyclohexane (chxn). All compounds were characterized through elemental analysis, infrared and UV/visible spectroscopies, and mass spectrometry in order to guarantee their purity and assess their charge transfer properties. The structures of 1a–c were determined via single-crystal X-ray diffraction studies. The geometries of cations of 1a–c and of molecules 2a–c were optimized through DFT calculations. The solid-state NLO behavior was measured by the Kurtz–Perry powder technique @1.907 µm. All chiral derivatives possess non-zero quadratic electric susceptibility (χ⁽²⁾) and an efficiency of about 0.15–0.45 times that of standard urea.

Boronic Acid Modified Polymer Nanoparticles for Enhanced Bacterial Deactivation

A new method has been developed to enhance the antibacterial efficiency of traditional antibiotics. Chloramphenicol-imprinted polymer particles were decorated with boronic acid to improve their binding to both Gram-negative and -positive bacteria. The polymer particles have a high antibiotic loading and provide a slow release of the antibiotic payload to deactivate the target bacteria. The boronic acid modified polymer particles not only contribute to enhanced antibacterial efficiency, but also have the potential to act as scavengers to remove unused antibiotic from the environment.

Preparation of Yolk-Shell-Structured Cox Fe1-x P with Enhanced OER Performance

The design and development of low-cost, highly efficient, and stable electrocatalysts to take the place of noble-metal catalysts for the oxygen evolution reaction (OER) remain a significant challenge. Herein, the synthesis of yolk-shell-structured binary transition metal phosphide Co_x Fe_1-x P with different Co/Fe ratios by phosphidation of a cobalt ferrite precursor is reported. The as-synthesized Co_x Fe_1-x P catalysts were used for the OER. All yolk-shell Co_x Fe_1-x P catalysts with different Co/Fe ratios showed much better performance than the corresponding solid catalyst. The formation of Co oxides on the catalyst surface during OER and the optimal Co/Fe ratio were found to be critical to their activity. Among the as-prepared Co_x Fe_1-x P catalysts, that with a Co/Fe ratio of 0.47/0.53 (Co_0.47 Fe_0.53 P) exhibited the best performance. Co_0.47 Fe_0.53 P has an overpotential of 277 mV at a current density of 10 mA cm^-2 , a Tafel slope of 37 mV dec^-1 , and superior stability in alkaline medium. The outstanding performance is partly ascribed to the transfer of valence electrons from Co to P and Fe. The Co_0.47 Fe_0.53 P matrix with excellent conductivity and Fe phosphate that is stable on the surface of the catalyst are also helpful for the OER performance. In addition, the yolk-shell structure of Co_0.47 Fe_0.53 P increases the contact area between electrolyte and catalyst. These characteristics of Co_0.47 Fe_0.53 P greatly improve its OER performance. This optimized binary transition metal phosphide provides a new approach for the design of nonprecious-metal electrocatalysts.

Colloidal Template Synthesis of Nanomaterials by Using Microporous Organic Nanoparticles: The Case of C@MoS2 Nanoadsorbents

The so-called colloidal template synthesis has been applied to the preparation of surface-engineered nanoadsorbents. Colloidal microporous organic network nanotemplates (C-MONs), which showed a high surface area (611 m²  g^-1 ) and enhanced microporosity, were prepared through the networking of organic building blocks in the presence of poly(vinylpyrrolidone) (PVP). Owing to entrapment of the PVP in networks, the C-MONs showed good colloidal dispersion in EtOH. MoS₂ precursors were incorporated into the C-MONs and heat treatment afforded core-shell-type C@MoS₂ nanoparticles with a diameter of 80 nm, a negative zeta potential (-39.5 mV), a high surface area (508 m²  g^-1 ), and excellent adsorption performance towards cationic dyes (q_max =343.6 and 421.9 mg g^-1 for methylene blue and rhodamine B, respectively).

Li-Ion Capacitor Integrated with Nano-network-Structured Ni/NiO/C Anode and Nitrogen-Doped Carbonized Metal-Organic Framework Cathode with High Power and Long Cyclability

Lithium-ion capacitors (LICs) represent a new type of energy-storage devices, which have combined merits of high energy density Li-ion battery and high power density supercapacitor. Nevertheless, one significant challenge for LICs is the imbalanced kinetics between the fast capacitive cathode and relatively slow intercalation anode that limit the energy-storage performance. Here, the asymmetric LIC devices were developed based on a nitrogen-doped, carbonized zeolitic imidazolate framework (ZIF-8) cathode and a three-dimensional, nano-network-structured, conversion reaction-based Ni/NiO/C anode. These nanostructures associated with both the cathode and anode enable rapid electron and ions transport in the LIC devices, which allows the asymmetric LICs to be operated on either high energy mode (energy density of 114.7 Wh/kg at power density of 98.0 W/kg) or high power mode (power density of 60.1 kW/kg at energy density of 17.6 Wh/kg). The device also exhibited long-term cycle stability with 87% capacitance retention after 12 000 cycles. These results demonstrate that the rational design of nanoporous electrode structures can deliver a balanced, high-performance-activated cZIF-8|Ni/NiO/C-based lithium-ion capacitor.

Isolation of Single-Wired Transition-Metal Monochalcogenides by Carbon Nanotubes

The successful isolation of single layers from two-dimensional (2D) van der Waals (vdW)-layered materials has opened new frontiers in condensed matter physics and materials science. Their discovery and unique properties laid the foundation for exploring 1D counterparts. However, the isolation of 1D vdW-wired materials has thus far remained a challenge, and effective techniques are demanded. Here we report the facile synthesis of isolated transition-metal monochalcogenide MoTe nanowires by using carbon nanotubes (CNTs) as molds. Individual nanowires are perfectly separated by CNTs with a minimal interaction, enabling detailed characterization of the single wires. Transmission electron microscopy revealed unusual torsional motion of MoTe nanowires inside CNTs. Confinement of 1D vdW-wired materials to the nanotest tubes might open up possibilities for exploring unprecedented properties of the nanowires and their potential applications such as electromechanical switching devices.

Size-Control by Anion Templating in Mechanochemical Synthesis of Hemicucurbiturils in the Solid State

Self-organization is one of the most intriguing phenomena of chemical matter. While the self-assembly of macrocycles and cages in dilute solutions has been extensively studied, it remains poorly understood in solvent-free environments. Provided here is the first example of using anionic templates to achieve selective assembly of differently-sized macrocycles in a solvent-free system. Using acid-catalyzed synthesis of cyclohexanohemicucurbiturils as a model, size-controlled, quantitative synthesis of 6- or 8-membered macrocycles by spontaneous anion-directed reorganization of mechanochemically-made oligomers in the solid state is demonstrated.

Dimensionality Expansion of a Butterfly Shaped Pd4 Framework: Constructing Edge-Sharing Pd6 Tetrahedra

The construction of well-defined transition-metal clusters has attracted substantial attention due to their unique chemical and/or physical properties. Metal clusters with 1D or 2D structures are now accessible by template-synthesis methods, in which multiple metal atoms are arranged with the aid of template molecules and their 1D or 2D structures. However, the rational synthesis of 3D clusters remains challenging, mostly due to a lack of appropriate template molecules. Herein, we report the rational synthesis of a 2D butterfly shaped Pd₄ framework (2) and 3D edge-sharing Pd₆ tetrahedra (5) by treatment of easily available organosilicon compounds with Pd(CNtBu)₂ . The diphenylsilylene moiety thereby serves as the key component to generate the butterfly structure of the Pd₄ clusters in 2. A dimensionality expansion, induced by two Cl atoms, of two butterfly shaped Pd₄ subunits supported by two diphenylsilylene moieties afforded the edge-sharing tetrahedral architecture of the Pd₆ cluster in 5.

Template Synthesis of an Ultrathin β-Graphdiyne-Like Film Using the Eglinton Coupling Reaction

β-Graphdiyne (β-GDY) is a two-dimensional carbon material with zero band gap and highly intrinsic carrier mobility and a promising material with potential applications in electronic devices. However, the synthesis of continuous single or ultrathin β-GDY has not been realized yet. Here, we proposed an approach for ultrathin β-GDY-like film synthesis using graphene as a template because of the strong π-π interaction between β-GDY and graphene. The as-synthesized film presents smooth and continuous morphology and has good crystallinity. Electrical measurement reveals that the film presented a conductivity of 1.30 × 10^-2 S·m^-1 by fabricating electronic devices on β-GDY grown on a dielectric hexagonal boron nitride template.