Effect of Non-Covalent Interactions on the 2,4- and 3,5-Dinitrobenzoate Eu-Cd Complex Structures

Heterometallic {Eu2Cd2} complexes [Eu2(NO3)2Cd2(Phen)2(2,4-Nbz)8]n·2nMeCN (I) and [Eu2(MeCN)2Cd2(Phen)2(3,5-Nbz)10] (II) with the 2,4-dinitrobenzoate (2,4-Nbz) and 3,5-dinitrobenzoate (3,5-Nbz) anions and 1,10-phenanthroline were synthesized. The compounds obtained were characterized by X-ray single-crystal analysis, powder X-ray diffraction analysis, IR spectroscopy, and elemental analysis. Moreover, the thermal stability of the complexes was also studied. Analysis of the crystal packing showed that where 1,10-phenanthroline is combined with various isomers of dinitrobenzoate anions, different arrangements of non-covalent interactions are observed in the complex structures. In the case of the compound with the 2,4-dinitrobenzoate anion, these interactions lead to a significant distortion of the metal core geometry and formation of a polymeric structure, while the complex with the 3,5-dinitrobenzoate anion has a structure that is typical of similar systems. The absence of europium metal-centered luminescence at 270 nm wavelength was shown. For all the reported compounds, a thermal stability study was carried out that showed that the compounds decomposed with a significant thermal effect.

Nanosized FeS/ZnS heterojunctions derived using zeolitic imidazolate Framework-8 (ZIF-8) for pH-universal oxygen reduction and High-efficiency Zn-air battery

Low-cost, stable, and highly active electrocatalysts for oxygen reduction reaction (ORR), especially for pH-universal ORR, are vital for developing numerous renewable energy devices. Herein, a hierarchical N, S-codoped porous carbon-based catalyst (ZFP-800) coupled with abundant FeS/ZnS heterojunctions was facilely prepared via direct pyrolysis of a Ferrocene-crosslinked pyrrole hydrogel composited with zeolitic imidazolate framework-8 (ZIF-8) templates. Compared with the heterojunction-free catalytic activity, the ZFP-800 catalytic activity was significantly higher in pH-universal ranges. Moreover, the ZFP-800 exhibited competitive ORR performance to commercial Pt/C (20%) in various electrolytes, in terms of onset (E_onset), half-wave potentials (E_1/2), limiting current density (J_L), durability, and methanol immunity. For instance, it exhibited super ORR catalytic activity on E_onset and E_1/2, and exceeded that of the benchmark Pt/C in both the alkaline and neutral media. Furthermore, the application of ZFP-800 as a cathode catalyst in a home-made Zn-air battery demonstrated its operation capability in ambient conditions with a competitive performance on the specific energy density (828 mA·h·g_Zn^-1), maximum discharge power density (205.6 mW·cm^-2), rate performance, and the long-term stability (188 h at 5 mA·cm^-2). This study can facilitate the development of advanced heterojunction-based materials for renewable energy applications.

Self-assembly and supramolecular isomerism in 1D metal–organometallic networks based on transition-metal assemblies from 1,1′-ferrocene-dicarboxylic acid and ancillary nitrogen heterocycle ligands

Eight novel 1D-MOMN's with different topologies were obtained from the self-assembly of M(ii) (M: Cu, Co, Cd, Zn), ancillary nitrogen ligands and bridging 1,1′-ferrocenedicarboxylate anions and characterized by X-ray diffraction techniques.

Single-Crystal Syntheses and Properties of Indium-Organic Frameworks Based on 1,1'-Ferrocenedicarboxylic Acid

Presented here are a series of indium-organic frameworks synthesized by the self-assembly of In³⁺ salts and 1,1'-ferrocenedicarboxylic acid (H₂FcDCA). Nitrogen-containing organic additives played various roles in the diversity of the structures. These compounds exhibit diverse frameworks with rich supramolecular interactions, which show good photoelectronic and redox activity together with active FcDCA ligands. Moreover, the indium-based MIL-53 analogue exhibited permanent porosity and gas separation.

Recent highlights and future prospects on mixed-metal MOFs as emerging supercapacitor candidates

Mixed-metal metal-organic frameworks (M-MOFs) consist of at least two different metal ions as nodes in the same framework. The incorporation of a second or more metal ions provides structural/compositional diversity, multi-functionality and stability to the framework. Moreover, the periodical array of different metal ions in the framework may alter the physical/chemical properties of M-MOFs and result in fascinating applications. M-MOFs with exciting structural features offer superior supercapacitor performances compared to single metal MOFs due to the synergic effect of different metal ions. In this review, we summarize several synthetic methods to construct M-MOFs by employing various organic ligands or metalloligands. Further, we discuss the electrochemical performance of several M-MOFs and their derived composite materials for supercapacitor applications.

Observation of three different linker conformers in a scandium ferrocenedicarboxylate coordination polymer

In the coordination polymer CAU-50 based on 1,1′-ferrocenedicarboxylate and scandium, three different conformers of the same linker molecule are observed.

Dy(III)-Based Metal-Organic Framework as a Fluorescent Probe for Highly Selective Detection of Picric Acid in Aqueous Medium

A dysprosium metal-organic framework, {[Dy(μ₂-FcDCA)_1.5(MeOH)(H₂O)]·0.5H₂O}_n (1), where FcDCA = 1,1'-ferrocene dicarboxylic acid, was prepared by slow-diffusion technique at room temperature. The crystal structure analysis of 1 by single-crystal X-ray diffraction reveals different binding modes of FcDCA linkers coordinated with Dy(III) metal ions, which forms continuous porous two-dimensional (2D) infinite framework. The resulting 2D layers are linked by π···π interactions to build three-dimensional (3D) supramolecular framework. Observably, this thermally stable 3D architecture was topologically simplified as a three-connected uninodal net with fes topology. Furthermore, the practical applicability of 1 was investigated as a fluorescence sensor for the sensitive detection of picric acid in aqueous medium with an impressive detection limit of 0.71 μM with quenching constant (K_SV) quantified to be 8.55 × 10⁴ M^-1. The distinguished selectivity in the presence of other nitroaromatics suggests the possible incorporation of 1 in real-world futuristic diagnostic kits. Additionally, the electrochemical behavior of 1 exhibits reversible in nature attributed to the ferrocene/ferrocenium cation.

A novel metal–organic framework based on hexanuclear Co(ii) clusters as an anode material for lithium-ion batteries

A new metal–organic framework, [Co(L)]·1.5H₂O (1), has been successfully synthesized, where its electrochemical application has been investigated.