Aiqing Ma

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.

A new Zn(II) metal–organic framework having 3D CdSO4 topology as luminescent sensor and photocatalyst for degradation of organic dyes

A new Zn(II) metal–organic framework, formulated as {[Zn(L)]·2.7 DMF} (1), was synthesized using a multidentate ligand 1,4-bis(triazol-1-yl)terephthalic acid (H2L). The MOF 1 adopts 3D uninodal 4-c CdSO4 topology and behaves as a luminescent chemosensor for highly selective and sensitive detection of Fe3+ and nitro-aromatics, particularly 2,4,6-trinitrophenol (TNP). In addition, the thermal stability, UV/Vis diffuse-reflection spectra and photocatalytic behaviors of 1 against organic dyes have also been investigated. The possible mechanism associated with the alleviation in the emission intensity of 1 in the presence of nitro-aromatic compounds were addressed by theoretical calculations. In addition, the photocatalytic activity of 1 against organic dyes was addressed using density of states (DOS) calculations.

Magnetism and Photocatalytic Degradation of Organic Dyes Based on a New Metal Formate Framework

A new MOF of [Co(HCOO)2] · 0.33DMF (I) was prepared and characterized by IR, powder X-ray diffraction, and single-crystal X-ray diffraction (CIF file CCDC no. 1571166). Complex I exhibits a diamond framework based on Co-centered CoCo4 tetrahedral nodes, in which all metal ions have octahedral coordination geometry and all HCOO groups link the metal ions in syn-syn/anti modes. The magnetic property shows a main antiferromagnetic interaction and the ferromagnetic phase transition below 2 K. Furthermore, the photocatalytic properties of I for degradation of the methyl violet and Rhodamine B have been explored.

Two Chemically Stable Cd(II) Polymers as Fluorescent Sensor and Photocatalyst for Aromatic Dyes

Two new 2D Cd(II)-based coordination polymers (CPs), viz. [Cd2(H2L)2(2,2’-bipy)2] (1) and [Cd(L)0.5(phen)·0.5H2O] (2), have been constructed using ethylene glycol ether bridging tetracarboxylate ligand 5,5′(4,4′-phenylenebis(methyleneoxy)) diisophthalic acid (H4L). Both CPs behaved as profound fluorescent sensor for Fe3+ ion and nitro-aromatics (NACs), specifically 2,4,6-trinitrophenol (TNP). The stability at elevated temperature and photocatalytic behaviors of both 1 and 2 for photo-decomposition of aromatic dyes have also been explored. An attempt has been made to explore the plausible mechanism related with the decrease in fluorescence intensity of 1 and 2 in presence of NACs using theoretical calculations. Additionally, the probable mechanism of photo catalysis by 1 and 2 to photo-degrade aromatic dyes has been explained using density of states (DOS) calculations.

Hydrogen-Bonded Organic–Inorganic Hybrid Based on Hexachloroplatinate and Nitrogen Heterocyclic Cations: Their Synthesis, Characterization, Crystal Structures, and Antitumor Activities In Vitro

Three new crystal structures containing [PtCl6]2−, pyridinium and benzimidazole groups have been prepared: [PtCl6]·(H-bzm)2·2(H2O) (1), [PtCl6]·(H-bipy)2·2(H2O) (2), [PtCl6]·(H-dimethyl-bipy)2·2(H2O) (3) [H-bzm: benzimidazole cation, H-bipy: 2,2′-bipyridine cation, H-dimethyl-bipy: 4,4′-bimethyl-2,2′-bipyridine cation]. All compounds have been fully characterized by elemental analyses, single-crystal X-ray analyses, IR spectra, TG analyses, and fluorescence studies. Single-crystal X-ray diffraction analysis suggests that the primary synthon contains +N–H···Cl−, including ionic bonding and hydrogen bonding interactions. The dimensions are enhanced further by secondary O–H ∙∙Cl and N–H ∙∙O hydrogen bonding interactions between donor and acceptor atoms located at the periphery of these synthons. Moreover, coulombic attractions between the ions play an important role in reinforcing the structures of these complexes. In addition, antitumor activity against human lung adenocarcinoma cell line (A549) and human nasopharyngeal carcinoma cell line (CNE-2) was performed. These complexes all showed inhibition to the two cell lines, while complex 3 exhibited higher efficiency than complexes 1–2.

Insights into the crystal structure of a polyoxomolybdate(VI) anion stabilized by ammonium cation: Inputs from X-ray diffraction and Hirshfeld surface analysis

A new polyoxomolybdate complex with chemical formula [NH2(CH3)2]4[Mo8O26] (I) has been synthesized and structurally characterized. Single-crystal X-ray analysis of compound I reveals that the ammonium cation generates an intricate 2D supramolecular architecture (CIF file CCDC no. 1026577). The detail analyses of Hirschfeld surface and fingerprint plots gave a mode of non-covalent interactions in the title compound.