A Luminescent 3D Organometallic Network Based on Silver Clusters and Star-like Tris(4-ethynylphenyl)amine

A star-like tris­(4-ethynylphenyl)­amine was used as a ligand to link Ag₃₀ and Ag₁₇ cluster units via argentophilic, Ag­(I)-ethynide, and Ag-nitrate interactions to construct one 3D organometallic network possessing small cavities. The solid network displays a yellowish-green emission at room temperature

A Luminescent 3D Organometallic Network Based on Silver Clusters and Star-like Tris(4-ethynylphenyl)amine

A star-like tris­(4-ethynylphenyl)­amine was used as a ligand to link Ag₃₀ and Ag₁₇ cluster units via argentophilic, Ag­(I)-ethynide, and Ag-nitrate interactions to construct one 3D organometallic network possessing small cavities. The solid network displays a yellowish-green emission at room temperature

Hydrogen-Bonded Framework of a Polyanionic Cluster and Its Growth from 2D to 3D for Dual-Selective Adsorption and pH-Controlled Oxidation

For fabricating a hydrogen-bonded framework with a stabilized hybrid structure for versatile functional properties, an inorganic polyanionic cluster that bears covalently grafted organic groups for hydrogen bond connection is synthesized. By modifying two guanine groups into a disklike polyoxometalate [Mn(OH)6Mo6O18]3– on both sides symmetrically, a polyanionic hybrid building block is obtained. With the cluster serving as a bridge and the grafted guanine unit serving as the binding sites, a polyoxometalate built-in hydrogen-bonded framework in the form of a square lattice shape within a two-dimensional plane has been fabricated as a single-layer assembly. In a further step, the counterion connection and hydrophilic/hydrophobic effect are used to drive the growth of layered framework assembly along the perpendicular direction. The resulting cluster-embedded framework possesses permanent porosity and inner-layer ionic characteristics after activation, which allows the framework to exhibit both high charge-/size-selective adsorption of organic cations and pH-controlled catalytic oxidation of methionine via the charged property

External Pressure Effect on a Twofold Interpenetrated 3D <i>PtS</i>-Type Spin-Crossover Coordination Polymer

A twofold interpenetrated three-dimensional iron coordination polymer with <i>PtS</i>-type topology, Fe (NCS)₂(TINM)•1/2TINM (<b>1</b>, TINM = tetrakis­(isonicotinoxymethyl)­methane), constructed by a semirigid tetradentate ligand, displays an incomplete spin-crossover behavior with <i>T</i>_1/2 at 118 K. Furthermore, the correlation between the external-pressure and spin transition is also discussed following theoretical approaches

Controlled Triol-Derivative Bonding and Decoration Transformation on Cu-Centered Anderson–Evans Polyoxometalates

To create new types of organic ligands covalently grafted onto polyoxometalates and identify the reaction mechanism, we selected Cu^II as the central heteroatom for the synthesis of a series of disklike Anderson–Evans clusters bearing different triol derivatives on both their faces via one-pot and/or step-by-step routes. By using a [(n-C₄H₉)₄N]₄[Mo₈O₂₆] precursor cluster and copper acetate as the starting materials, several organically modified χ isomers with Cu^II heteroatom centers were obtained. Starting from a [(n-C₄H₉)₄N]₂[Mo₂O₇] subcluster, however, a half-malposition coordination fashion of triol ligands with a δ isomer on one face and a χ isomer on the other face of the Anderson–Evans cluster was obtained. By changing the reaction solvent from acetonitrile to methanol, we realized a secondary organic modification of the triol-grafted clusters and obtained a triol ligand/methanol codecoration on the Anderson–Evans polyoxometalate. In addition, by changing the reaction environment, we succeeded in modulating the transformation of triol ligands from one site to another on the polyoxometalate cluster. Importantly, by control of the reaction condition, the methanol molecules were also taken off from the cluster

Modulating Charge Transfer Pathways to Enhance Photocatalytic Performance of the Metal–Organic Layer Nanosheet

Two-dimensional metal–organic layer (MOL) nanosheets, as nonhomogeneous catalysts, show better optical activity in the field of photocatalysis due to their unique structural advantages. Current research focuses on how to modify the structure of 2D nanosheets by means of crystal engineering to modulate the intralayer electron transfer pathway and systematically investigate the impacts of size effect and electron transfer pathway on the energy utilization efficiency of crystalline materials. In the present work, a triple lophine-derived ligand was designed and prepared, which exhibits a large π-conjugation system and multiple D–A (D: donor, A: acceptor) electron transfer pathways. 2D MOL constructed with Cd ions can be exfoliated by physical sonication to obtain double-walled 2D MOL nanosheets. Compared with the bulk crystalline material, the 2D nanosheets exhibit better photovoltaic properties. Benefiting from the excellent structural advantages, 2D MOL nanosheets could be used as photocatalysts for a variety of aerobic oxidation reactions under mild conditions (10 W white LED, room temperature), such as the trifluoromethylation of coumarins, the synthesis of benzimidazole derivatives from aromatic diamines and aromatic aldehydes, and the preparation of 2,4,6-triarylpyridine derivatives, all with high conversion rates and selectivity (yield typically greater than 88%). The related results illustrate that the introduction of the photoactive triple-lophine unit into 2D MOL nanosheets can effectively modulate the electron transport mode and enhance energy utilization, which provides a new research idea for the development of nonhomogeneous photocatalysts aimed at the applications of visible light-driven organic conversion

Solvent Dielectricity-Modulated Helical Assembly and Morphologic Transformation of Achiral Surfactant-Inorganic Cluster Ionic Complexes

Ionic complexes comprising single/double chain cationic surfactant and Lindqvist-type polyoxomolybdate anionic cluster were used for controlled self-assembly in organic solutions. In the solvent with low dielectric constant the complexes self-assembled into flat ribbon like lamellar aggregations with an inverse bilayer substructure where the cluster located at the middle. Under the condition of increased dielectric constant, the solvent triggered the formation of helical self-assemblies, which finally transformed from helical ribbons to the flower-like assemblies due to the bilayer becoming excessively twisted. The self-assembled morphology and the substructure were characterized by SEM, TEM, and XRD. The solvent dielectricity-controlled morphologic transformations modulated by the variation of electrostatic interactions between organic cations and inorganic polyanions were demonstrated by ¹H NMR and IR spectra. The strategy in this work represents an effective route in targeting the chirality-directed functionalization of inorganic clusters by combining controllable and helical assemblies of achiral polyoxometalate complexes in one system

In Situ Grown Coordination-Supramolecular Layer Holding 3D Charged Channels for Highly Reversible Zn Anodes

Dynamic reversible noncovalent interactions make supramolecular framework (SF) structures flexible and designable. A three-dimensional (3D) growth of such frameworks is beneficial to improve the structure stability while maintaining unique properties. Here, through the ionic interaction of the polyoxometalate cluster, coordination of zinc ions with cationic terpyridine, and hydrogen bonding of grafted carboxyl groups, the construction of a 3D SF at a well-crystallized state is realized. The framework can grow in situ on the Zn surface, further extending laterally into a full covering without defects. Relying on the dissolution and the postcoordination effects, the 3D SF layer is used as an artificial solid electrolyte interphase to improve the Zn-anode performance. The uniformly distributed clusters within nanosized pores create a negatively charged nanochannel, accelerating zinc ion transfer and homogenizing zinc deposition. The 3D SF/Zn symmetric cells demonstrate high stability for over 3000 h at a current density of 5 mA cm–2

Preface

A new version of molecular clip, with a semi-rigid symmetrical crab-type architecture and flexible cavity size, has been successfully designed and synthesized via a one-pot Friedel–Crafts alkylation reaction. The X-ray single-crystal diffraction data provide a simple and intuitive explanation, not only for its well-preorganized and regulated conformation but also for its selective and tunable guest-binding capability. For the first time, the newly designed molecular clip was demonstrated to be not only a controllable variable-speed nonporous adsorption material in solution iodine capture, but also capable of on–off switching in volatile iodine capture. The presented new concept of molecular crystal gearshift directly from the molecular clip crystals represents an important advance in the development of synthetic receptor chemistry, which will exert a significant influence on small-molecule crystallography

Modulating Charge Transfer Pathways to Enhance Photocatalytic Performance of the Metal–Organic Layer Nanosheet

Two-dimensional metal–organic layer (MOL) nanosheets, as nonhomogeneous catalysts, show better optical activity in the field of photocatalysis due to their unique structural advantages. Current research focuses on how to modify the structure of 2D nanosheets by means of crystal engineering to modulate the intralayer electron transfer pathway and systematically investigate the impacts of size effect and electron transfer pathway on the energy utilization efficiency of crystalline materials. In the present work, a triple lophine-derived ligand was designed and prepared, which exhibits a large π-conjugation system and multiple D–A (D: donor, A: acceptor) electron transfer pathways. 2D MOL constructed with Cd ions can be exfoliated by physical sonication to obtain double-walled 2D MOL nanosheets. Compared with the bulk crystalline material, the 2D nanosheets exhibit better photovoltaic properties. Benefiting from the excellent structural advantages, 2D MOL nanosheets could be used as photocatalysts for a variety of aerobic oxidation reactions under mild conditions (10 W white LED, room temperature), such as the trifluoromethylation of coumarins, the synthesis of benzimidazole derivatives from aromatic diamines and aromatic aldehydes, and the preparation of 2,4,6-triarylpyridine derivatives, all with high conversion rates and selectivity (yield typically greater than 88%). The related results illustrate that the introduction of the photoactive triple-lophine unit into 2D MOL nanosheets can effectively modulate the electron transport mode and enhance energy utilization, which provides a new research idea for the development of nonhomogeneous photocatalysts aimed at the applications of visible light-driven organic conversion