Jiang-Feng Song

A novel 3D Cu(I) coordination polymer based on Cu6Br2 and Cu2(CN)2 SBUs: in situ ligand formation and use as a naked-eye colorimetric sensor for NB and 2-NT.

A novel coordination polymer with the chemical formula [Cu4Br(CN)(mtz)2]n (mtz = 5-methyl tetrazole) (), has been synthesized under solvothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. Interestingly, the Cu(i), CN(-) and mtz(-) in compound are all generated from an in situ translation of the original precursors: Cu(2+), acetonitrile and 1-methyl-5-mercapto-1,2,3,4-tetrazole (Hmnt). The in situ ring-to-ring conversion of Hmnt into mtz(-) was found for the first time. Structural analysis reveals that compound is a novel 3D tetrazole-based Cu(i) coordination polymer, containing both metal halide cluster Cu6Br2 and metal pseudohalide cluster Cu2(CN)2 secondary building units (SBUs), which shows an unprecedented (3,6,10)-connected topology. Notably, a pseudo-porphyrin structure with 16-membered rings constructed by four mtz(-) anions and four copper(i) ions was observed in compound . The fluorescence properties of compound were investigated in the solid state and in various solvent emulsions, the results show that compound is a highly sensitive naked-eye colorimetric sensor for NB and 2-NT (NB = nitrobenzene and 2-NT = 2-nitrotoluene).

Homochiral imidazole-based dicarboxylate metal complexes with SrSi2 topology: synthesis, crystal structures, and properties

Two new complexes with homochiral frameworks, {Co3(EIDC)2(H2O)5}n (1) and {Zn3(EIDC)2(H2O)4}n (2) (H3EIDC = 2-ethyl-1H-imidazole-4,5-dicarboxylic acid), have been synthesized from achiral starting precursors via spontaneous resolution and fully characterized by elemental analyses, IR, circular dichroism, photoluminescence (PL) spectroscopy, single-crystal X-ray diffraction, and thermogravimetric analysis. X-ray diffraction data revealed that 1 and 2 have SrSi2 topologies and that both are homochiral metal–organic frameworks. Compound 1 is constructed by left-handed chiral chains; however, right-handed chains constitute the homochiral framework of 2. Variable temperature magnetic susceptibility measurements of 1 indicate strong antiferromagnetic interactions between the magnetic Co centers. Compound 2 exhibited weak blue PL in the solid state at room temperature. Graphical Abstract Two novel homochiral frameworks with SrSi2 topology, {Co3(EIDC)2(H2O)5}n (1) and {Zn3(EIDC)2(H2O)4}n (2) (H3EIDC = 2-ethyl-1H-imidazole-4,5-dicarboxylic acid), have been synthesized from totally achiral starting precursors via spontaneous resolution. The homochiral natures of 1 and 2 were further confirmed by circular dichroism spectra.

Solvent-induced construction of two zinc supramolecular isomers: synthesis, framework flexibility, sensing properties, and adsorption of dye molecules

Two zinc supramolecular isomers, formulated as α-[Zn(cis-cppca)(H2O)]n (1) and β-[Zn(trans-cppca)(H2O)]n (2), have been synthesized under solvothermal conditions and fully characterized (H2cppca = 5-(3-carboxy-phenyl)-pyridine-2-carboxylic acid). Solvent-induced conformational isomerism of cppca2− ligand and framework isomerism of 1 and 2 are both observed. Each distorted [Zn(cis-cppca)]2 unit joined four equivalent ones in an abnormal 2D puckered layer in compound 1; however, compound 2 displays a 3-D open framework with larger bi-edge channels constructed by 1D Zn–O–Zn chains and trans-cppca bridges, in which the internal edge is a nearly hexagonal channel with an approximate dimension of 14.51 A and the external edge is a circular channel with an approximate dimension of 19.26 A. Fluorescent properties indicated that compound 1 displays an apparent fluorescence emission in acetone solvent; however, compound 2 was very sensitive to acetone molecules which results in nearly 100% fluorescence quenching. Moreover, compounds 1 and 2 might be promising luminescent probes for the detection of Fe3+. The dye adsorption experiments demonstrated that compound 2 showed good adsorption properties for MB and RhB molecules.

Six new coordination compounds based on rigid 5-(3-carboxy-phenyl)-pyridine-2-carboxylic acid: synthesis, structural variations and properties

Six new coordination compounds Ni(cppca)(H2O)4·2H2O (1), Co(cppca)(H2O)4·2H2O (2), {Cd2(cppca)2(H2O)5}n (3), {[Cd3(cppca)2(H2P2O7)(H2O)6]·2H2O}n (4), {Cu(Hcppca)2}n (5) and {[Mn7(cppca)6(Hcppca)2(H2O)10]·2H2O}n (6) have been obtained by reactions of the corresponding metal salts and the rigid ligand 5-(3-carboxy-phenyl)-pyridine-2-carboxylic acid (H2cppca) under solvothermal conditions. All the compounds were fully characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, thermal analysis and powder X-ray diffraction. The single-crystal X-ray analyses showed that compounds 1–6 have rich structural chemistry ranging from mononuclear (1 and 2), one-dimensional (3 and 4), two-dimensional (5) to three-dimensional (6) structures. Moreover, the framework of compound 6 may be simplified into a 3-nodal net with Schlafli symbol {42·6}{42·82·102}{43·62·8·104}2, which shows an unprecedented (3,4,5)-connected topology net. The fluorescent properties of compounds 3 and 4 were investigated in the solid state and in various solvent emulsions, which indicated that compounds 3 and 4 are both highly sensitive fluorescent probes for the acetone molecules. Variable-temperature magnetic susceptibility measurements indicate weak antiferromagnetic interactions between metal centers in compounds 1, 2, 5 and 6.

A new inorganic 2D framework based on Bi-bismuth-capping Keggin polyoxometalate with photodegradation and selective absorption of organic dyes

A new purely inorganic 2D framework, {PMo12O40Bi2(H2O)2}·4H2O(1), was synthesized under solvothermal condition and characterized by infrared(IR) spectroscopy, thermal gravimetric analysis, UV-Vis spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. Structural analysis reveals that compound 1 consists of Keggin unit {PMo12O40} with two bismuth atoms capping two opposite pits, leading to the bi-bismuth-capping Keggin polyoxometalate. Compound 1 not only displays excellent photodegradation activity for methyl orange(MO), but also has a high absorption capacity for rhodamine B(RhB) and methylene blue(MB). Moreover, compound 1 is extremely stable and easily separated from the reaction system for reuse.

Three new complexes based on methyl-pyrimidine-2-thione: in situ transformation, crystal structures and properties

Abstract Three complexes based on methyl-pyrimidine-2-thione, 5-methyl-5,8,9,10-tetrahydro-5,9methanopyrimido[5,4-e][1, 3]diazocine-2,7-dithiol (mtmdd) (1), and Ni(mpymt)2(N2H4)·H2O (2) and [Cd(mpymt)2]∞ (3) have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared (IR) spectroscopy, thermal gravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analysis reveals that 1 is generated from an in situ translation of mpymt. In 2, two Ni(mpymt)2 fragments were joined into a dinuclear complex by two NH2–NH2 molecules. Compound 3 is a two-dimensional Cd coordination polymer constructed by Cd2(mpymt)2 SBUs and mpymt anions. Variable-temperature magnetic susceptibility measurement of 2 revealed strong antiferromagnetic interactions between nickel magnetic centers. The fluorescent properties of 1 and 3 were investigated in the solid state.

Five metal imidazole dicarboxylate-based compounds comprising M3(MIDC)2 entities (M = Zn2+, Co2+, Mn2+): syntheses, structures and properties

Five metal imidazole dicarboxylate-based compounds, {[Zn3(MIDC)2(4,4′-bipy)3](4,4′-bipy)·8H2O}n (1), {[Co3(MIDC)2(4,4′-bipy)3](4,4′-bipy)·6H2O}n (2), {[Co3(MIDC)2(py)2(H2O)2]}n (3), {[Mn6(MIDC)4(py)5(H2O)4]}n (4), and {[Mn3(MIDC)2(Phen)3(H2O)2]}n (5) (H3MIDC = 2-methyl-1H-imidazole-4,5-dicarboxylic acid; 4,4′-bipy = 4,4′-bipyridine; py = pyridine; Phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectroscopy, thermogravimetric analysis, and single-crystal X-ray diffraction. We control the coordination modes of H3MIDC via hydrazine and obtained a series of coordination compounds containing honeycomb-like [M3(MIDC)2]n layers. We also investigated the effects of different neutral terminal or bridging ligands on [M3(MIDC)2]n layers. Coplanar [M3(MIDC)2]n layers and 4,4-bipy were used to construct 3-D frameworks of 1 and 2. Puckered [M3(MIDC)2]n layers were found in 3–5; 4 is the first [M3(L)2]n layer structure with two crests and troughs during each period (L = imidazole-4,5-dicarboxylic acid or its analog). Compound 5 is the first puckered [M3(L)2]n layer structure decorated by chelating neutral ligands. Compound 1 exhibits weak blue photoluminescence in the solid state at room temperature. Variable-temperature magnetic susceptibility measurements of 2–5 indicate strong antiferromagnetic interactions. Graphical abstract Using a method, which can effectively control the coordination mode of H3MIDC, we constructed a series of new coordination compounds containing honeycomb-like [M3(MIDC)2]n layers.

Syntheses and crystal structures of four new fpa-metal complexes through in situ ligand reaction

Four new fpa-metal complexes, [Co(fpa)2(H2O)2] (1), [Cu(fpa)2(H2O)] (2), [Zn2(fpa)4(bpp)2] n (3), and {[Zn(bpy)(H2O)4] · 2(fpa)} n (4), have been synthesized and fully characterized by elemental analyses, IR spectroscopy, single-crystal X-ray diffraction, and thermogravimetric analysis (TGA), (Hfpa = 2,2-difluoro-2-(pyridine-2-yl)acetate, bpp = 1,3-bis(4-pyridyl)propane, bpy = 4,4′-bipyridine). X-ray diffraction analyses reveal that 1 and 2 with 0-D structures are both extended into 3-D supramolecular networks through hydrogen bonds and π···π interactions. Complex 3 with chiral centers possesses a 1-D structure constructed by two kinds of bpp molecules and four kinds of fpa− molecules with different conformations, with bbp and fpa− bridging and capped ligands, respectively. In 4, bpy links [Zn(H2O)4]2+ into a 1-D polymeric cationic chain and uncoordinated fpa− compensates the framework charge. The results of TGA reveal that fpa− decomposes through two processes. Both 3 and 4 show strong fluorescence in the solid state at room temperature.

Pressurized carbonization of mixed plastics into porous carbon sheets on magnesium oxide

Conversion of waste thermoplastics into porous carbons has attracted wide attention due to the requirement of recycling of large quantities of municipal solid waste. This work reports the preparation of porous carbon sheets on magnesium oxide from mixed thermoplastics including polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyethylene terephthalate in a closed autoclave at 500 °C. The influence of the weight ratio of magnesium oxide to mixed plastics on the yield and textural properties of the carbon was examined. The morphology and structure of the porous carbon were also characterized. The maximum BET surface area was 713 m2 g−1 at a weight ratio of MgO/polymer of 4 and the maximum pore volume was 5.27 cm3 g−1 at a weight ratio of MgO/polymer of 6. The reaction mechanism was explored by analyzing the product distribution and composition of gas and liquid at different reaction times. Aromatics were the main source for the growth of carbon. Model experiments of carbonization of different aromatics were conducted to evaluate the carbonization reactivity of aromatics. Polycyclic aromatic hydrocarbons, especially acenes, produced more carbon.

Naked eye colorimetric multifunctional sensing of nitrobenzene, Cr(VI) and Fe(III) with a new green emission Ag6S6 multi-metal-cluster

AbstractWith the increasing need of detecting chemical pollutants, modern analytical instruments show many advantages but also have some common drawbacks such as high operational cost and tedious pretreatment procedures. Thus, developing a fast, simple, and convenient colorimetric sensing system is a challenge. Here, a new Ag6S6 cluster-based coordination compound formulated as Ag6(dmpymt)6 (1) (Hdmpymt = 4,6-dimethylpyrimidine-2-thione) was synthesized under solvothermal condition and displayed apparently green luminescence emission and good stabilities in water and some organic solvents. Fluorescence experiments illustrated that 1 displayed efficiently naked eye colorimetric sensing for nitrobenzene (NB), Cr(VI), and Fe(III) ions by fluorescence quenching in the emulsions. The possible sensing mechanisms are attributed to the competitive absorption of excitation wavelength energy between the analytes and the compound 1. Furthermore, the fluorescent test papers of 1 were prepared as well and showed efficient, convenient, and easily recycled characteristics, presenting a potential sensing application for the environmental concerns. Graphical abstractA new Ag6S6 multi-metal-cluster-based luminescent test papers display efficiently naked eye colorimetric sensing of nitrobenzene, Cr(VI) and Fe(III).