Zinc‐based Metal Organic Framework Derived From Anthracene and BODIPY Chromophores: Synthesis and Photophysical Properties

Removal of organic dyes from aqueous solution using a novel pyrene appended Zn(II)-based metal-organic framework and its photocatalytic properties

In this study, we report the efficient removal of organic dyes from aqueous solutions using a newly synthesized pyrene-appended Zn(II)-based metal-organic framework (MOF), ZnSiF6Pyrene MOF, with the chemical formula C52H32F6N4SiZn·4(CHCl3). The MOF was synthesized through a facile method at room temperature using a dipyridylpyrene ligand and ZnSiF6 metal source, resulting in a highly crystalline structure with pyrene functional groups forming the framework. The synthesized MOF was characterized using various analytical techniques, including Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD) analysis, and scanning electron microscopy (SEM). Thermal stability was assessed using thermogravimetric analysis (TGA), while the surface area of the MOF was determined using a Brunauer-Emmett-Teller (BET) surface analyzer. Furthermore, the single-crystal X-ray diffraction (SCXRD) structure was studied to authenticate its solid-state structure. The as-synthesized MOF exhibited remarkable adsorption capacity towards various organic dyes, including Congo red (CR), rhodamine B (RhB), and methyl violet (MV), due to its ample surface area and strong π-π interactions between the pyrene moieties and dye molecules, as demonstrated by experimental and in silico docking studies. The photocatalytic degradation of MV dye was also investigated. Detailed trapping tests indicate that hydroxyl (˙OH) and superoxide (O2˙-) radicals are likely the primary active species responsible for the photodegradation of the dye under study. Furthermore, the photocatalytic property of the MOF was investigated under visible light irradiation, demonstrating excellent ability to generate singlet oxygen. This study highlights the potential of pyrene-appended Zn(II)-based MOFs as promising materials for environmental remediation applications.

Multifunctional Chiral d10-Metal Coordination Polymers: Tunable Photoluminescence and Efficient Second-Harmonic Generation with Circular Dichroic Response

A series of homochiral coordination polymers (HCPs), [M2(SIAP)2(bpy)2] [M(S)] and [M2(RIAP)2(bpy)2] [M(R)] (M = Zn or Cd, SIAP or RIAP = (S,S)- or (R,R)- 2,2'-(isophthaloylbis(azanediyl))di-propionic acid, bpy = 4,4'-bipyridine), is successfully synthesized through solvothermal reactions, self-assembling d10 metal cations, chiral dicarboxylic ligands, and π-conjugated bipyridyl ligands. The HCPs crystallize in the extremely rare triclinic chiral space group, P1, and present 3D framework structures attributed to the strong intermolecular interactions, such as hydrogen bonds and π-π stacking. Due to the unique crystal structures, the title compounds reveal efficient photoluminescence emission across a broad visible range, with significant brightness and color tuning by varying the excitation wavelength. Moreover, they exhibit efficient phase-matched second-harmonic generation (SHG) with very high laser-induced damage thresholds, essential for high-power nonlinear optical (NLO) applications. Intriguingly, the title compounds exhibit a measurable contrast in the SHG response under right- and left-handed circularly polarized excitation, thereby providing a unique case of SHG circular dichroism from the chiral centers of SIAP2- or RIAP2- ligand packed in the noncentrosymmetric environment. These exceptional attributes position these HCPs as promising candidates for multifunctional materials, with potential applications ranging from NLO devices to tailored luminescent systems with polarization control.

A mixed-ligand Co metal-organic framework and its carbon composites as excellent electrocatalysts for the oxygen evolution reaction in green-energy devices

Oxygen evolution reaction (OER) electrocatalysts are frequently made from noble metal-based oxides like ruthenium/iridium oxides. However, because of their scarcity and high price, researchers are now focusing on creating innovative OER catalysts based on affordable transition metals that have improved electrical conductivity and accessibility to active sites. Metal-organic frameworks (MOFs), a unique class of inorganic materials with excellent physical and chemical properties, have witnessed significant progress in promising green energy systems. In this work, a novel mixed-ligand metal-organic framework [Co(μ-1κN,2κN'-BDP)(μ3-1κoo',2κo''2κo'''-BTC)]n·nH2O (BDP = boron-dipyrromethene or BODIPY; BTC = benzene tricarboxylate) denoted as CoBDPMOF has been synthesized, and its composites with different carbon materials have been designed. Compared to the pristine MOF, the composites showed enhanced electrocatalytic activity toward the oxygen evolution reaction (OER) in alkaline media. In addition, the CoBDPMOF with activated carbon showed the highest OER performance with a low Tafel slope (82 mV dec-1) and the highest j600 (59.8 mA cm-2), outperforming noble metal IrO2, the OER benchmark electrocatalyst. This study presents new insights into the design and application of CoBDPMOF-based materials for energy conversion and suggests promising avenues for further research and development in electrocatalysis.

Ti-Based porous materials for reactive oxygen species-mediated photocatalytic reactions

Reactive oxygen species (ROS) are highly reactive oxidants that are typically generated by the irradiation of semiconducting materials with visible or UV light and are widely used for the photocatalytic degradation of toxic substances, photodynamic therapy, and selective organic transformations. In this context, TiO2 is considered to be among the most promising photocatalysts due to its high redox activity, structural stability, and natural abundance. In view of the extensive development of highly active photocatalysts, we herein briefly introduce TiO2 and the mechanisms of TiO2-mediated ROS generation, subsequently focusing on key advances in the design and synthesis of Ti-containing porous materials, such as porous TiO2, Ti-based metal-organic frameworks, and Ti-based metal-organic aerogels. In particular, this review highlights the significance of porosity and the structure-function relationship for the development of Ti-based photocatalysts. The structures, porosities, and ROS generation mechanisms of these materials as well as the related efficiencies of ROS-mediated photocatalytic organic transformations are discussed in detail to provide a useful reference for future researchers and to inspire the exploration of high-performance photocatalysts.