Syntheses, design strategies, and photocatalytic charge dynamics of metal–organic frameworks (MOFs): a catalyzed photo-degradation approach towards organic dyes

The presented review focuses on design strategies to develop tailor-made MOFs/CPs of main group, transition and inner-transition elements and their photocatalytic properties to decompose dyes in wastewater discharge and their photocatalytic mechanism.

Coordination Polymers Based on Highly Emissive Ligands: Synthesis and Functional Properties

Coordination polymers are constructed from metal ions and bridging ligands, linking them into solid-state structures extending in one (1D), two (2D) or three dimensions (3D). Two- and three-dimensional coordination polymers with potential voids are often referred to as metal-organic frameworks (MOFs) or porous coordination polymers. Luminescence is an important property of coordination polymers, often playing a key role in their applications. Photophysical properties of the coordination polymers can be associated with intraligand, metal-centered, guest-centered, metal-to-ligand and ligand-to-metal electron transitions. In recent years, a rapid growth of publications devoted to luminescent or fluorescent coordination polymers can be observed. In this review the use of fluorescent ligands, namely, 4,4'-stilbenedicarboxylic acid, 1,3,4-oxadiazole, thiazole, 2,1,3-benzothiadiazole, terpyridine and carbazole derivatives, naphthalene diimides, 4,4',4''-nitrilotribenzoic acid, ruthenium(II) and iridium(III) complexes, boron-dipyrromethene (BODIPY) derivatives, porphyrins, for the construction of coordination polymers are surveyed. Applications of such coordination polymers based on their photophysical properties will be discussed. The review covers the literature published before April 2020.

Synthesis, structure and photocatalytic properties of coordination polymers based on pyrazole carboxylic acid ligands

The photocatalytic activities of two novel different 2-D coordination polymers constructed from 5-hydroxy-1H-pyrazole-3-carboxylic acid ligand have been explored.

Hydrothermal synthesis of two 2D uranyl coordination polymers: structure, luminescence, and photocatalytic degradation of rhodamine B

Two hydrothermal synthesized uranyl-organic coordination polymers showing effective photocatalytic activities for RhB degradation with quick equilibrium time in water.

Cu(ii)/Ni(ii)–organic frameworks constructed from the homometallic clusters by 5-(2-carboxyphenoxy)isophthalic acid and N-ligand: synthesis, structures and visible light-driven photocatalytic properties

Four new complexes, namely, Cu₂(O-cpia)(btb)_0.5·(OH) (1), Cu₃(O-cpia)₂(bpy)₂ (2), [Ni₂(O-cpia)(phen)·(OH)·H₂O]·2H₂O (3) and [Ni₃(O-cpia)₂(bpy)₃·2H₂O]·2H₂O (4) (O-cpia = 5-(2-carboxyphenoxy)isophthalic acid, btb = 1,4-bis(1,2,4-triazol-1-yl)butane, bpy = 4,4′-bipyridine) were successfully isolated under hydrothermal conditions. The four complexes exhibit different architectures constructed from different homometallic clusters varying from mononuclear, binuclear to tetranuclear metal(ii) polyhedra as Second Building Blocks (SBUs). 1 features a 3D framework constructed from the tetranuclear clusters [Cu₄(μ₃-OH)₂] as SBUs, linked with Cu(1)O₄N and Cu(2)O₅ polyhedra by O-cpia/btb mixed linkers. 2 also exhibits a 3D structure based on trinuclear clusters [Cu₃(COO)₄] SBUs, bridged with Cu(1)O₃N₂ and Cu(2)O₄ polyhedra via O-cpia/bpy mixed ligands. 3 shows a 2D network consisting of tetranuclear clusters [Ni₄(μ₃-OH)₂] SBUs, which are bridged with Ni(1)O₄N₂ and Ni(2)O₆ through O-cpia ligands. It is worth noting that 4, with a 3D structure, is generated from the binuclear clusters [Ni₂(COO)₄] (Ni(1)O₄N) and mononuclear metal Ni(2) cores (Ni(2)O₄N₂) as SBUs, and bridged by O-cpia/bpy mixed ligands. Meanwhile, the degradation of dyes (RhB) by the complexes under visible light irradiation was studied. 1–4 are semiconducting in nature, with E_g of 1.30 eV (1), 1.78 eV (2), 2.85 eV (3) and 2.14 eV (4). Cu(ii) complexes 1 and 2 are highly efficient photocatalysts for the degradation of RhB under visible light irradiation.

Four Cu(ii)/Ni(ii)-metal–organic frameworks were constructed from different homometallic clusters by O-cpia/N-ligands. Cu(ii)-complexes show highly efficient photocatalysts for the degradation of RhB under visible light irradiation.

Construction of novel Ag/HKUST-1/g-C3N4 towards enhanced photocatalytic activity for the degradation of pollutants under visible light

A novel Ag/metal–organic framework/graphitic carbon nitride (Ag/HKUST-1/g-C₃N₄, AHC) photocatalyst was prepared via an in situ growth strategy and photo-deposition technique for environmental remediation. The as-obtained samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), N₂ adsorption–desorption isotherm measurement, UV-vis diffuse reflection spectroscopy (UV-vis DRS), and photoluminescence (PL) spectroscopy. The results indicated that the hybrids have large surface area, mesoporous structure and enhanced visible-light absorption. The as-prepared hybrid samples exhibited considerable improvement in photocatalytic activity and stability for rhodamine B (RhB) degradation under visible light irradiation (λ > 420 nm). In addition, they also have good adsorption properties. Compared to the pure g-C₃N₄ and Ag/g-C₃N₄, the 5% AHC photocatalyst showed superior photocatalytic activity. Moreover, 5% AHC exhibits good photocatalytic activity even after four cycles. Additionally, the active species trapping and electron spin resonance (ESR) experiments indicated that h⁺ and ·OH were the main active species.

A novel AHC photocatalyst was prepared via in situ growth strategy and photo-deposition technique. The as-prepared hybrid samples have good photocatalytic activity and stability for Rh B degradation under visible-light irradiation.