Polyoxometalate-Templated Cobalt-Resorcin[4]arene Frameworks: Tunable Structure and Lithium-Ion Battery Performance

Abstract

By employing a bowl-like tetra­(benzimidazole)­resorcin[4]­arene (TBR4A) ligand, two new polyoxometalate-templated metal–organic frameworks (POMOFs), [Co8Cl14(TBR4A)6]·3­[H3.3SiW12O40]·10DMF·11EtOH·20H2O (1) and [Co3Cl2(TBR4A)2(DMF)4]·[SiW12O40]·2EtOH·3H2O (2), have been prepared under solvothermal conditions (DMF = N,N′-dimethylformamide). 1 shows a 2D cationic layer, whereas 2 exhibits a 3D framework. Remarkably, the Keggin POMs in 1 and 2 were located in the cavities formed by two bowl-like resorcin[4]­arenes in sandwich fashions. Their framework structures were highly dependent on the coordination modes of the TBR4A ligands. To increase the conductivity of POMOFs, the samples of 1 and 2 were loaded on the conductive polypyrrole-reduced graphene oxide (PPy-RGO) via ball milling (1@PG and 2@PG). Then, the obtained composites experienced calcination at a proper temperature to produce 1@PG-A and 2@PG-A. The resulting 1@PG-A and 2@PG-A composites, with improved conductivities, uniform sizes and micropores, exhibited promising electrochemical performance for lithium-ion batteries. We herein proposed a size-controlled route for the rational fabrication of functional POMOFs and their usage in energy fields.

A series of polyoxometalate-based COF composites by one-pot mechanosynthesis of thioether to sulfone

“…It can not only avoid agglomeration and improve their dispersion but also further enhance their catalytic activity owing to the possible synergistic catalytic effect between Keggin-POMs and porous materials. [22][23][24][25][26][27][28] Thus, it is key to select excellent porous materials as carriers of Keggin-POMs. [29][30][31][32][33] Covalent organic frameworks (COFs) are a recently developed class of porous materials with flexible structural designability and high stability.…”

Polyoxometalate‐Incorporated CuI‐Resorcin[4]arene Metal‐Organic Complexes as Heterogeneous Catalysts for Catalytic Oxidation of Mustard Gas Simulant

“…In this context, functionalized resorcin[4]arene with multi‐chelating groups has been selected as fantastic organic ligand candidate to construct POM‐incorporated metal–organic complexes [42–45] . This mainly benefits from their macrocyclic structures and easily modified upper and lower edges [46–53] …”

Two Copper-Containing Polyoxometalate-Based Metal–Organic Complexes as Heterogeneous Catalysts for the C–H Bond Oxidation of Benzylic Compounds and Olefin Epoxidation

“…Polyoxometalates (POMs) have unique redox properties and modifiable Lewis acidity, but their inherent poor stability and tendency to aggregate in solution have hindered further development. Taking these into account, POM-based metal–organic complexes (MOCs), which normally contain POM units and possess open network structures, have demonstrated a massive potential of application for organic catalysis as heterogeneous catalysts. − Compared to discrete POMs or MOCs, POM-based MOCs combine the advantages of POMs and MOCs and exhibit stronger structural stability. − In the construction of POM-based MOCs, an important strategy is to use the POM units with unique structures and properties as the inorganic templates connected to the metal–organic units through noncovalent bonding interaction. − At present, there have been some reports on various POM-based MOCs constructed with Keggin-type POMs as templates. − …”