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Unprecedented double S2− templated Ag27 clusters have been stabilized by 5,10,15,20‐tetra(4‐pyridyl)porphyrin (TPyP‐H2) ligands to afford a robust 2D metal–organic framework (Ag27‐MOF). This silver cluster‐assembled material serves as a highly efficient heterogeneous catalyst for the cyclization of both terminal and internal propargylamines with CO2 under atmospheric pressure. Density functional theory (DFT) calculations illustrate that the high catalytic activity and broad substrate scope are attributable to the saddle‐shaped metallic node in Ag27‐MOF, which features an accessible platform with high‐density silver atoms as π‐Lewis acid sites for activating C≡C triple bonds. As a result, different sterically hindered alkyne substrates can be effectively activated through π‐interactions with these cationic silver centers. [ABSTRACT FROM AUTHOR]

Abstract: Two unique ZnI‐containing MOFs {[ZnI8ZnII3(H2O)x(HL)12](OH)2⋅13 H2O}n (x=6, 1; x=2, 2) (HL=tetrazole monoanion) with high‐nuclearity Zn‐cages were prepared successfully. These Zn‐cages are constructed from [ZnI8] clusters with multi‐centered ZnI−ZnI bonds and ZnII ions. [ZnI8] clusters in 1 and 2 display Oh and D4h symmetry, respectively. Importantly, eight [ZnI8] clusters and six ZnII ions form a large [Zn70] nanocage in 1. To our knowledge, this is the first MOF based on polynuclear Zn‐cages consisting of ZnI and ZnII ions. Compared with reported ZnI‐species, 1 and 2 display high thermal and solvent stabilities. Theoretical investigations based on DFT calculations uncover that effective 4s‐4s orbital overlap and electron delocalization through these a1g+t1u molecular orbitals on [ZnI8] clusters lead to considerable aromatic stabilization, which can explain well the intrinsic stability of 1 and 2. Interestingly, 1 can behave as a luminescent probe to detect the toxic CrVI ions in aqueous. [ABSTRACT FROM AUTHOR]

MOFs with both multicentered metal-metal bonds and low-oxidation-state (LOS) metal ions have been underexplored hitherto. Here we report the first cubic [MnI8] cluster-based MOF ( 1) with multicentered MnIMnI bonds and +1 oxidation state of manganese (MnI or Mn(I)), as is supported by single-crystal structure determination, XPS analyses, and quantum chemical studies. Compound 1 possesses the shortest MnIMnI bond of 2.372 Å. Theoretical studies with density functional theory (DFT) reveal extensive electron delocalization over the [MnI8] cube. The 48 electrons in the [MnI8] cube fully occupy half of the 3d-based and the lowest 4s-based bonding orbitals, with six electrons lying at the nonbonding 3d-orbitals. This bonding feature renders so-called cubic aromaticity. Magnetic properties measurements show that 1 is an antiferromagnet. This work is expected to inspire further investigation of cubic metal-metal bonding, MOF materials with LOS metals, and metalloaromatic theory. [ABSTRACT FROM AUTHOR]

Two lanthanide-based frameworks: {Ln(phen)(NDA) 1.5 (H 2 O)} n (Ln=Gd( 1 ), NDA=2,6-naphthalenedicarboxylate anion, phen=1,10-phenanthroline), and {[Dy(phen)(NDA) 1.5 ]·0.5H 2 NDA} n ( 2 ) were structurally and magnetically characterized. Compound 1 exhibits 2D layer structure, belonging to the triclinic system with space group P −1, while compound 2 features a 3D framework with space group P −1. The magnetic studies revealed that ferromagnetic coupling existed between adjacent lanthanide ions in 1 and 2 , and frequency-dependence out-of-phase signals in the measurement of alternate-current susceptibilities were observed for 2 , albeit without reaching the characteristic maxima above 2 K, implying slow magnetic relaxation behavior in 2 . After the application of a dc field, good peak shapes of ac signal were obtained and got the energy barrier Δ E / k B =29 K and the pre-exponential factor τ 0 =4.47×10 −7 s at 2000 Oe field; and when the dc field was in 5000 Oe, giving Δ E / k B =40 K and τ 0 =2.82×10 −6 . [ABSTRACT FROM AUTHOR]

Ca2+ ion leaching and poor pore structure are obstacles of CaO for biodiesel production. To this end, a typical Zr–based metal organic framework, UiO–66(Zr) is adopted to support calcium acetate to prepare CaO/ZrO 2 catalyst. For comparison, catalyst precursor is activated in nitrogen (UCN) and air (UCA) atmosphere, respectively. Preparation factors including calcium acetate addition and activation temperature are evaluated. Moreover, effects of transesterification parameters on oil conversion are investigated and the optimized parameters are further used to examine catalyst reusability. Meanwhile, catalysts are characterized with TG, XRD, XPS, FTIR, Hammett indicator titration, N 2 adsorption and desorption. Results reveal UCN calcined at 650 °C (UCN650) and UCA calcined at 700 °C (UCA700) separately exhibits the best catalytic performance. The maximum conversion of 96.99% is achieved by UCN650 with catalyst amount of 6 wt% and molar ratio of methanol to oil of 9 at 65 °C for 60 min. Even after being used 3 cycles, conversion of 92.76% is still achieved by UCN650. By contrast, UCA700 shows lower conversion of 92.94% at the first cycle with catalyst amount of 8 wt% and molar ratio of methanol to oil of 9 at 65 °C for 60 min. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The syntheses, design strategies, and structural descriptions of MOFs based on 1H-pyrazole-4-carboxylic acid are discussed succinctly. • Structural features such as dimensionality, topology, porosity, and their applications are elaborated in detail. • Diverse supramolecular assemblies generated through mixed secondary building units (SBUs) via the combination of mixed metals and mixed linkers are highlighted. • The results and important future prospects of MOFs based on 1H-pyrazole-4-carboxylic acid are proposed. Metal-organic frameworks (MOFs), consisting of metal ions or clusters coordinated with organic ligands, are a class of crystalline materials that have garnered widespread prominence recently due to their unique and tunable properties, forming extended 3D frameworks with well-defined porous structures. Their exceptional chemical and structural properties have captured the attention of researchers worldwide, making them an exciting avenue for developing innovative materials with diverse applications. In particular, MOFs containing ligands with carboxylic acid and N-containing moieties hold great promise for designing novel architectures suitable for various applications. The engineered flexibility and host–guest interaction chemistry of these MOFs make them excellent candidates for pioneering materials. This review presents an inclusive summary of the latest progress in pyrazolate carboxylate MOF design, focusing on their applications in sensing, catalysis, drug delivery, and luminescence. We also introduce the synthetic process and synergistic effects of MOFs in execution. Finally, we briefly outline the obstacles, opportunities, and implications for future development in these areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • The syntheses, design strategies and structural descriptions of adenine-based MOFs are briefly discussed. • The structural features such as dimensionality, topology, porosity and their applications are described in detail. • Diverse supramolecular architectures and photophysical properties due to non-covalent interactions are highlighted. • The outcomes and important future aspects of adenine-based MOFs are proposed. Metal-organic frameworks (MOFs) endowed with unique structural features, namely permanent porosity, high surface area, tunable pore size, and potential applications in diverse domains, have garnered immense attention in recent decades. The availability of large numbers of organic linkers, metal nodes, and multiple synthetic tactics has broadened the scope of MOF research wherein the judicial selection of building blocks, and especially the organic linker is critical for the task-specific MOF design. The adenine nucleobase is an ideal choice among the broadly available organic linkers because of its small size, being nitrogen-riched and non-toxic, and its ready availability comprising multiple Lewis basic coordination sites and modes. In addition, adenine with its amino group (–NH 2) can network through non-covalent interfaces (host and guest) rather than covalent interactions, i.e., hydrogen bonding via Watson-Crick (N1, N6H) and Hoogsteen (N7, N6H) face contact, thus making ensued adenine-based MOF materials more appealing. Herein, we appraise the general introduction of syntheses and design strategies, the structural influence of adenine incorporation to the ensued attributes of MOFs, and their applications in diverse research fields such as gas storage (selective adsorption of CO 2), separation, luminescence, drug delivery, catalysis, and sensing. [ABSTRACT FROM AUTHOR]