Zhidong Luo

Luminescent sensing and photocatalytic degradation properties of an uncommon (4,5,5)-connected 3D MOF based on 3,5-di(3′,5′-dicarboxylphenyl)benzoic acid

An uncommon microporous metal–organic framework (MOF), {[Zn5(L)2(DMF)2(μ3-H2O)]·2DMF} (1), was successfully constructed using a less exploited symmetrical pentacarboxylate ligand, 3,5-di(3′,5′-dicarboxylphenyl)benzoic acid (H5L). The MOF 1 features a trinodal (4,5,5)-connected topology having a Schlafli symbol of (42·63·8)(45·65)2(46·64) and is stable in air as well as in acidic/basic aqueous media at room temperature. The MOF 1 behaves as a luminescent sensor for the highly selective and sensitive detection of Fe3+, Fe2+, Cu2+ and Ag+ ions and o-nitrophenol (MNP), p-nitrophenol (PNP), 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP) and 4-nitrotoluene (4-NT). Furthermore, the photocatalytic properties of 1 for the degradation of Methyl violet (MV) and Rhodamine B (RhB) have been explored. The possible quenching of the emissions of 1 in the presence of nitroaromatics has been addressed by theoretical calculations and the photocatalytic activity of 1 against organic dyes has been addressed using density of states (DOS) calculations.

Fluorescence detection of Mn2+, Cr2O72− and nitroexplosives and photocatalytic degradation of methyl violet and rhodamine B based on two stable metal–organic frameworks

The reaction of Zn(NO3)2·6H2O/Cd(NO3)2·4H2O with a semi-flexible ligand 4′-(4-(3,5-dicarboxylphenoxy)phenyl)-4,2′:6′,4′′-terpyridine (H2dbp) gave two new metal–organic frameworks of [Zn(dbp)]n (1) and [Cd(dbp)(H2O)·2H2O·CH3CN]n (2). Single crystal X-ray diffraction analyses reveal that both 1 and 2 show three-dimensional, two-fold interpenetrating four-connected networks with 44.610.8 topology. The photoluminescence investigation indicates that both 1 and 2 could be prospective candidates for developing luminescence sensors for the sensing of Mn2+, Cr2O72− and nitroaromatic analytes. Furthermore, the photocatalysis properties of 1–2 for the degradation of methyl violet and rhodamine B were examined.

Two lanthanide-based metal–organic frameworks for highly efficient adsorption and removal of fluoride ions from water

The contamination of water with fluoride (F−) is a source of mounting concern for global public health, and the removal of fluoride is quite important and challenging. In this study, two new lanthanide-based metal–organic frameworks (MOFs), {[Ce(L1)0.5(NO3)(H2O)2]·2DMF} (1) and [Eu3(L2)2(OH)(DMF)0.22(H2O)5.78]·guest (2) (H4L1 = 2,5-di(3′,5′-dicarboxylphenyl)benzene and H4L2 = 3,5-bis(isophthalic acid)-1H-1,2,4-triazole) are designed, synthesized and characterized. Both MOFs are tested for their adsorption capacity for fluoride ions and different uptake times from contaminated water. The investigation indicates that 1 displays a much higher adsorption capacity (103.95 mg g−1) and faster uptake rates (1.79 g mg−1 min−1) for fluoride ion than that of 2. The presented investigation is the first report in which lanthanide-based MOFs are used for the removal of fluoride ions from water.

Microporous Metal–Organic Framework Based on Ligand-Truncation Strategy with High Performance for Gas Adsorption and Separation

By using the ligand-truncation strategy, a microporous metal-organic framework (1) with high surface area was designedly synthesized. MOF 1 shows a new (4, 4)-connected net with a Schläfli symbol of (44.62)(43.62.8)2(42.82.102) and exhibits a high H2 capture capacity (193 cm3 g-1 at 1 atm and 77 K) and selectivities for CO2 over N2 and CH4 at low pressure.

A porous zinc(II) metal–organic framework exhibiting high sensing ability for ferric and nitroaromatics as well as photocatalytic degradation activities against organic dyes

Abstract A NbO-type Zn(II) metal–organic framework of {[Zn2(HL)(H2O)2]∙H2O}n (1) has been developed using a pentacarboxylate 2,5-bis(3′,5′-dicarboxylphenyl)-benzoic acid (H5L) ligand and characterized. The single-crystal X-ray diffraction studies indicate that 1 comprises free –COOH groups and Zn(II) centers bridged by four carboxylate groups to form a paddle wheel SBU which is further connected by L5− ligands to build a 3-D porous network with two types of cages. The chemically stable MOF 1 behaves as a highly selective and sensitive fluorescent chemosensor for the detection of Fe3+ ions, 2,4,6-trinitrophenol (TNP), which is known to be an extremely hazardous and strong explosive. Furthermore, the photocatalytic properties of 1 for degradation of methyl violet (MV) and Rhodamine B (RhB) have been explored. The possible emission quenching mechanism in the presence of nitro-aromatics (NACs) has been addressed by theoretical calculations and photocatalytic activity of 1 against organic dyes has been supported using density of states (DOS) calculations.

A 3D Stable Metal–Organic Framework for Highly Efficient Adsorption and Removal of Drug Contaminants from Water

We herein selected a 3D metal–organic framework decorated with carboxylate groups as an adsorbent to remove the pharmaceutical molecules of diclofenac sodium and chlorpromazine hydrochloride from water. The experiment aimed at exploring the effect factors of initial concentration, equilibrium time, temperature, pH and adsorbent dosage on the adsorption process. The adsorption uptake rate of the diclofenac sodium is much higher than that of the chlorpromazine hydrochloride. This paper presents the high adsorption capacity of diclofenac sodium, in which porous MOFs are used for the removal of drug contaminants from water. According to linear fitting with adsorption isotherm equation and kinetic equations, diclofenac sodium conforms to the Langmuir model and pseudo-first-order kinetic equation, while chlorpromazine hydrochloride accords with the Temkin model and pseudo-second-order kinetic equation. The results of the study indicate that the title compound could be a promising hybrid material for removing diclofenac sodium and chlorpromazine hydrochloride from wastewater.

Metal–Organic Framework (MOF)-based Nanomaterials for Biomedical Applications

Metal-organic frameworks (MOFs) are compounds consisting of metal ions or clusters coordinated to organic ligands to form one-, two-, or three-dimensional structures. They are a subclass of coordination polymers (CPs), with the special feature that they are often porous. The organic ligands are sometimes referred to as second building structs. The new porous materials have paid great attention because of the variety of advantages such as tunable components, structural diversity, high loading performance and favorable biodegradability. In this review, we highlighted the recent progress on the drug delivery application of MOFs, especially emphasizing the application of pH-responsive delivery as well as magnetic-guided drug delivery systems (DDSs). Subsequently, the applications of MOFs in magnetic resonance imaging (MRI), optical imaging (OI), X-ray computed tomography (CT) imaging and multimodality imaging will be discussed. Finally, we will provide an overview for the photodynamic therapy and the toxicity feature of MOFs.