Xi-Ren Wu

An uncommon (5,5)-connected 3D metal organic material for selective and sensitive sensing of nitroaromatics and ferric ion: experimental studies and theoretical analysis

An unexploited pentacarboxylate ligand, 2,5-bis(3′,5′-dicarboxylphenyl)-benzoic acid (H5L), was designed and used for the preparation of metal organic material using Zn2+ as a node. The new compound, {(Me2NH2)[Zn2(L)(H2O)]·0.5DMF}n (1) (DMF = dimethylformamide), has been synthesized and structurally characterized. The topology of the 5-connected anionic framework may be described as (44)(66) (Schlafli symbol) based on {M2(CO2)5} molecular building blocks (MBBs) and L ligands in 1. It has been demonstrated that 1 can act as a fluorescent sensor for highly sensitive detection of nitroaromatics and Fe3+, with a detection limit of 0.54 ppm for 2,4,6-trinitrophenol (TNP) and 0.81 ppm for Fe3+. The possible emission quenching mechanism in the presence of nitroaromatics has been addressed by theoretical calculations.

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.

A 2D Cd(II)-MOF as a multifunctional luminescencent sensor for nitroaromatics, iron(III) and chromate ions

Abstract A Cd(II)-MOF, {[Cd(L)(4,4′-bipy)]·H2O·DMF}n (1) (L = nicotinic acid (2,4-dihydroxybenzylidene)-hydrazide and 4,4′-bipy = 4,4′-bipyridine), has been synthesized and characterized by microanalyses, FTIR, TGA, and single-crystal X-ray diffraction. Additionally, powder X-ray diffraction was performed to check the phase purity of the synthesized compound. Single-crystal X-ray diffraction reveals that 1 has a 2D grid network. Photoluminescent sensing of nitrobenzene, Fe(III) and CrO42− ions indicates that 1 could be a candidate for developing selective luminescent sensors for these species. Theoretical calculations have been performed to gain insight into the possible mechanism of quenching effect in emission on addition of nitrobenzene in 1 which supports the mechanism operating through ground state charge transfer between 1 and nitrobenzene.

The utilization of a stable 2D bilayer MOF for simultaneous study of luminescent and photocatalytic properties: experimental studies and theoretical analysis

A new Pb(II)-based 2D MOF comprising π-conjugated ligand 4′-(1H-tetrazol-5-yl)-[1,1′-biphenyl]-3,5-dicarboxylic acid (TZBPDC) and having the formula {[PbNa(TZBPDC)](H2O)(DMF)2}n (1) has been synthesized. Structural characterization of 1 indicates that the MOF has a 4-connected (4,4) motif. The photoluminescent investigation indicates that 1 can behave as potential luminescent sensor for the detection of nitroaromatic compounds (NACs), especially 2,4-dinitrophenol (2,4-DNP) and ferric ions, through the decrease in its luminescence intensity. Additionally, 1 also displays excellent capacity for the photodegradation of methylene orange (MO), which is a constituent of wastewater discharge. The most plausible mechanisms for the decrease in the luminescent intensity of 1 in the presence of different NACs have been explored though theoretical calculations, and the photocatalysis of 1 for organic dyes has been addressed using density of states (DOS) and partial DOS calculations.

Syntheses, Hirshfeld surface analyses and magnetism of two complexes with flexible carboxylates

ABSTRACT Two Cu-based complexes with chemical formulae {[Cu2(L)3(2,2′-bipy)2]·NO3·2H2O}(1) and {[Cu2(L)2(H2O)2(phen)2]·2NO3·H2O} (2) (HL˭3-(4-hydroxyphenyl)propanoic acid) have been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compounds 1 and 2 have dinuclear Cu(II) units linking by carboxylate groups. The chelating N-donor ligands with 2,2′-bipy and phen bind to Cu(II) centers and there are weaker Cu-Cu bond interactions as well. The detailed analyses of Hirshfeld surface and fingerprint plots provide insight into the nature of noncovalent interactions in the title compounds. Furthermore, the magnetic properties of compounds 1 and 2 and related atoms-in-molecule calculations were discussed in detail.

A new metal-organic framework constructed from tetracarboxylate: Structure, magnetism and simulation

ABSTRACT A new metal-organic framework of [Cu2(L)(H2O)2]·2DMF (1) (H4L = quaterphenyl-3,3′″,5,5′″-tetracarboxylic acid) has been prepared and characterized. It has the NbO-derived topology that was observed in MOF-505. Magnetic study reveals the overall antiferromagnetic interactions between neighboring Cu(II) ions in compound 1. In addition, we performed an optimization by semiempirical PM5 method simulations to investigate the loading of 5-FU to 1 at the molecular level.

Synthesis and Magnetism of a Dimeric Complex

A new Cu-based complex of {[Cu2(L)2(phen)2(NO3)]·NO3} (1) (HL = p-hydroxy phenylacetic acid, phen = 1,10-phenanthroline) has been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compound 1 has a dinuclear Cu(II) unit linking by two carboxylate groups and one nitrate group. The chelating N-donor ligand with phen binds to Cu(II) centers and there is weaker Cu-Cu bond interaction as well. Furthermore, the magnetic property of compound 1 was discussed in detail.

Synthesis, Hirshfeld surface analyses and magnetism of a 1D Mn(II) complex

A new Mn-based complex of {[Mn(L) 2 (mi)]·H 2 O} n ( 1 ) (HL = p -hydroxy phenylacetic acid; mi = 1,1’-(1,4-butanediyl)bis(imidazole)), has been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compound 1 has a dinuclear Mn(II) unit linking by four carboxylate groups. The bridging N-donor ligand with mi links the Mn(II) centers into a 1D double chain. The detailed analyses of Hirschfeld surface and fingerprint plots provide insight into the nature of non-covalent interactions in the title compound. Furthermore, an attempt was made to explain the magnetic property of compound 1 using atoms in molecule (AIM) theory. KEY WORDS : Supramolecular architecture, Hirschfeld surface analysis, Magnetism Bull. Chem. Soc. Ethiop. 2016 , 30(1), 111-118. DOI: http://dx.doi.org/10.4314/bcse.v30i1.10

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.

A new supramolecular Cd(II) complex with unusual solid-state properties constructed from rigid coligand

A new complex with chemical formulae [Cd2(L)(IP)4(H2O)2 · L · 4H2O] (I) (H2L = terephthalic acid, IP = 1-H-imidazo[4,5-f][1,10]-phenanthroline) has been synthesized and structurally characterized by single-crystal X-ray diffraction analysis (CIF file CCDC no. 1004954). The structural determination revealed that I has a dimeric motif, which can be further linked into 2D network via the three different hydrogen bonding interactions. In addition, the luminescent behavior of compound I was also explored.