Two Metal-Organic Frameworks with a Fused Cis-Decalin Conformation for Multimedia Iodine Capture

The extensive growth of nuclear power plants has a severe detrimental effect on human health and the surroundings due to the uncontrolled and unfiltered release of radioactive wastes into the environment. One such radioactive waste is 129I which has a fatal effect when released into the air or water bodies. Hence, molecular and ionic iodine capture from multimedia has become an important area of interest in the recent past. This work is aimed at introducing two 2D metal-organic frameworks with a fused cis-decalin conformation, {[Zn2(tpbn)(fdc)2]·6H2O}n (1) and {[Cd2(tpbn)(fdc)2(H2O)2]·2H2O}n (2), synthesized at room temperature utilizing a combination of M(OAc)2·2H2O (M: Zn/Cd), a neutral flexible ligand, tpbn, and a simple commercially available furan dicarboxylate, fdc2-, for the target application. The polarizing nature of the furan moieties and the oxygen rich pores in 1 and 2 facilitate the easy capture of molecular iodine from both the vapor phase and aqueous media with high uptake values. Furthermore, their efficiency was tested for the practical application under real-world conditions using river and seawater. In addition to confirming their recyclability with the retention of structural integrity, the interaction between 1 and 2 with iodine has also been established with experimental and theoretical calculations.

In situ self-assembled macroporous interconnected nanosheet arrays of Ni-1,3,5-benzenetricarboxylate metal - organic framework on Ti mesh as high-performance oxygen evolution electrodes

Highly efficient metal-organic framework (MOF)-based oxygen evolution reaction (OER) catalysts are desirable for water splitting, but their development remains challenging due to poor accessibility of coordinatively unsaturated metal (cum) sites and low intrinsic activity. A large-area three-dimensional (3-D) macroporous interconnected nanosheet array of Ni-1,3,5-benzenetricarboxylate has been in situ self-assembled on Ti mesh (TM) by using ethanol as the solvent and high-affinity oxide layer on TM to promote in situ nucleation. The obtained nanoarchitecture exhibits much superior catalytic activity compared to most reported catalysts including MOF-based catalysts, other precious-metal-free ones, and Ir/Ru-based ones. Additionally, this electrode undergoes no current decay after 300 cyclic voltammetry (CV) cycles and can maintain at 250 mA cm^-2 for over 266 h. The excellent catalytic performance is mainly due to the 3-D macroporous and interconnected nanosheet array structure improving cum site exposure and charge transport and in situ activated cum cations enhancing OH^- adsorption. This work not only develops a facile and economical approach to synthesize 3-D macroporous interconnected MOF nanosheet arrays to simultaneously increase the number, exposure, and intrinsic activity of active sites and facilitate charge transport for high-performance eletrocatalysis, but provides scientific insights into the mechanisms for self-assembly of this unique nanoarchitecture and for the high OER performance.

Conductive bimetal organic framework nanorods decorated with highly dispersed Co3O4nanoparticles as bi-functional electrocatalyst

The poor electronic conductivity and low intrinsic electrocatalytic activity of metal organic frameworks (MOFs) greatly limit their direct application in electrocatalytic reactions. Herein, we report a conductive two-dimensionalπ-dconjugated Ni and Co bimetal organic framework (MOF)-NiCo-(2,3,6,7,10,11-hexaiminotriphenylene) (NiCo-HITP) nanorods decorated with highly dispersed Co₃O₄nanoparticles (NPs) as a promising bi-functional electrocatalyst towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) through an effective and facile strategy by modifying the rod-shaped -Ni₃HITP₂crystals using cobalt ions. The triggered electrocatalytic activity of the resulting MOF-based materials was achieved by increasing the electrical conductivity (7.23 S cm^-1) originated from Ni₃HITP₂substrate and also by creating the cooperative catalysis sites of Co-N_xand Co₃O₄NPs. Optimized syntheses show a promising ORR activity with a high half-wave potential (0.77 V) and also a significantly improved OER activity compared with pure Ni₃HITP₂in alkaline electrolyte. Furthermore, a rechargeable Zn-air battery using the as-prepared material as air-cathode also shows a high power density (143.1 mW cm^-2)-even comparable to a commercial Pt/C-RuO₂-based battery. This methodology offers a new prospect in the design and synthesis of non-carbonized MOF bi-functional electrocatalysts for efficient catalysis towards ORR and OER.

Ultrathin nanosheet-assembled nickel-based metal-organic framework microflowers for supercapacitor applications

Herein, we propose a solvent-assisted approach for preparing Ni-MOF microflowers with high specific capacitance and excellent rate capability as an electrode material for supercapacitors. The high electrochemical performance of this Ni-MOF is attributed to the fast ion transport and low electrical resistance resulting from its hierarchical flower-like structure, and the capacitance contribution from nickel hydroxide species.

The effect of solvent on one-dimensional cadmium coordination polymers

We transformed one one-dimensional coordination polymer directly to another by carrying out a dissolution–recrystallization structural transformation (DRST).

Multifunctional copper dimer: structure, band gap energy, catalysis, magnetism, oxygen reduction reaction and proton conductivity

A new copper dimeric complex has been synthesized, characterized and used as a multifunctional material.

Three luminescent metal–organic frameworks constructed from trinuclear zinc(ii) clusters and furan-2,5-dicarboxylate

Three metal–organic frameworks constructed from trinuclear zinc(ii) clusters and furan-2,5-dicarboxylate with different topology were hydrothermally synthesized by adjusting the anions and solvent. Moreover, the blue luminescence of the complexes was investigated.