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The pKa1 values and NBO charges of 32 carboxylate ligands and 31 N-heterocyclic ligands were calculated at 298.15 K with the B3LYP/6-31+G(d,p) level of calculations, which are useful to understand the water and thermal stability of Metal–Organic Frameworks (MOFs).

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The crystalline structure and dielectric properties of Sm1.5Sr0.5NiO4 ceramics are presented. The present ceramics is refined as orthorhombic Bmab phase and the orthorhombic strain may change the statue of charge ordering. The temperature-stable giant dielectric constant (∼100 000) with low dielectric loss of ∼0.1 is observed at frequency up to 5 MHz over a broad range of temperature (150–500 K) and frequency (100 kHz–5 MHz). The grain interior should be the dominative factor which contributes the giant dielectric response in the present ceramics after the equivalent circuit fitting, and the thermal activated small polaronic hopping related to the charge ordering is that factor. Compared to other giant dielectric materials, the present materials have a great potential in the practical application, especially for the high frequency application.

Although single metal atoms (SMAs) have been extensively investigated as unique active sites in single-atom catalysts, the possible active sites of the host catalysts have been unfortunately neglected in previous studies.

A new (4,8)-connected Zr-MOF porous zirconium metal-organic framework (Zr-MOF) with flu topology, Zr6(μ3-O)4(μ3-OH)4(TCPS)2(H2O)4(OH)4 (, TCPS = tetrakis(4-carboxyphenyl) silane) with a BET specific area of 1402 m(2) g(-1) has been constructed and fully characterized. is stable in air and acid media but unstable in water and basic media, and thermally stable up to 200 °C. The new MOF is a wide band gap semiconductor with Eg = 3.95 eV. The excitation of at 260 nm gives a ligand-based emission peak at 435 nm. After solvent exchange processes and activation at 200 °C, this MOF exhibits high storage capacities for H2, CH4 and CO2. We summarized the hydrothermal stability data of Zr-MOFs, calculated the NBO (natural bond orbital) charges of the coordinating oxygen atoms of the corresponding carboxylate ligands and analyzed the influencing factors. Besides the known reasons of hydrothermal stabilities of Zr-MOFs, we demonstrated that NBO charges of coordinating atoms of the ligands can be used to explain the hydrothermal stabilities of Zr-MOFs.