Chong-Chen Wang

Ultra-high uptake and selective adsorption of organic dyes with a novel polyoxomolybdate-based organic–inorganic hybrid compound

A novel organic–inorganic hybrid compound, (4-Hap)4[Mo8O26] (4-ap = 4-aminopyridine) (1), was synthesized via a hydrothermal method, and utilized to conduct adsorptive uptake of typical organic dyes, in which some key parameters of dye adsorption were investigated. The results revealed that compound 1 demonstrated rapid adsorption of methylene blue (MB) with ultra-high efficiency and capacity, as well as achieving rapid and highly selective adsorption of MB from MB/MO (MO = methyl orange) and MB/RhB (RhB = rhodamine B) mixtures.

Synthesis, characterization, and luminescent properties of a series of silver(I) complexes with organic carboxylic acid and 1,3-bis(4-pyridyl)propane ligands

The reaction of AgNO3 with combinations of 1,3-bis(4-pyridyl)propane (bpp), pyridine-3,5-dicarboxylic acid (H2pdc), oxybis(benzoic acid) (H2oba), and 4,4′-oxidiphthalic acid (H4odpt) in aqueous alcohol/ammonia at room temperature produces crystals of [Ag2(bpp)2](pdc)·8H2O, [Ag2(bpp)2(H2O)](oba)·5H2O, and [Ag2(bpp)2(H2O)2](odpt)·2H2O. All three complexes consist of 1D infinite silver-bpp cationic chains, interspersed with organic carboxylate anions that provide charge compensation in the crystal structures. The lattice water molecules are situated among the framework of the crystal structure and show rich hydrogen-bonding interactions, which serve to orientate the organic carboxylate anions in the crystal packing, while the presence of Ag···N and Ag···Ag contacts strengthens the frameworks. The luminescent properties of the complexes have been investigated.

Influence of organic carboxylic acids on self-assembly of silver(I) complexes containing 1,2-bis(4-pyridyl)ethane ligands

Four silver(I) complexes, namely [Ag2(bpe)2](bdc)·8H2O (1), [Ag2(bpe)2(da)]·4H2O (2), [Ag4(bpe)3(bptc)]·9H2O (3), and Ag(bpe)2(bpdc)2 (4), have been successfully synthesized by the reactions between AgNO3, 1,2-bis(4-pyridyl)ethane (bpe) and different carboxylic acids, including 1,3-benzenedicarboxylic acid (H2bdc), diphenic acid (H2da), 3,3′,4,4′-biphenyltetracarboxylic acid (H4bptc), and 2,2′-bipyridine-3,3′-dicarboxylic acid (H2bpdc). All four compounds were characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction. In (1), the Ag(I) atoms, in linear geometry, are joined into 1-D infinite cationic bpe-silver chains, and discrete bdc2− anions compensate the charge of the crystal structure. In (2), the Ag(I) atoms, adopting tetrahedral and trigonal geometries, are linked by bpe and da2− ligands into neutral double chains. In (3), the Ag(I) atoms, in T-shaped and linear environments, are coordinated by bpe and multidentate bptc4− ligands to construct a 2-D network. And in (4), the Ag(I) atoms, with trigonal and T-shaped coordination geometries, are coordinated by bpe and bpdc2− ligands to build up a 3-D framework. The different anions play different and important roles in directing the final crystal structures.

Synthesis, structure, and luminescent properties of three silver(I) complexes with organic carboxylic acid and 4,4′-bipyridine-like ligands

The reactions of AgNO3 with combinations of 1,2-bis(4-pyridyl)ethane(bpa)/4,4′-bipyridine (bpy), 4,4′-stilbenedicarboxylic acid (H2sda)/2,2′-diphenylaminedicarboxylic acid (H2dpadc)/2,6-naphthalenedicarboxylic acid (H2ndc) in aqueous alcohol/ammonia at room temperature produce block-like crystals of [Ag2(bpa)1.5(sda)0.5](sda)0.5·7H2O, [Ag2(bpa)2(H2O)3](dpadc), [Ag2(bpy)2](ndc)·4H2O. All three complexes consist of 1D infinite silver–ligand cationic chains, interspersed with organic carboxylate anions that provide charge compensation in the crystal structures. The lattice water molecules are situated among the framework of the crystal structure and show rich hydrogen-bonding interactions, which help to orientate the organic carboxylate anions in the crystal packing, and the presence of Ag···N and Ag···Ag contacts contributes to strengthen the frameworks. The luminescent properties and thermogravimetric analyses of the three complexes are also presented.

Adsorption of methylene blue and methyl violet by camellia seed powder: kinetic and thermodynamic studies

AbstractAdsorption of methylene blue (MB) and methyl violet (MV) onto camellia seed powder (CSP) was conducted, and the equilibrium data were fitted with Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models to describe the equilibrium isotherms. The kinetics rates were modeled using pseudo-first-order, pseudo-second-order kinetic equations, and intra-particle diffusion model. The results revealed that adsorption of MB and MV onto CSP was affected slightly by the pH value, and the maximum adsorption amount was achieved at the pH of 5.5, the unadjusted value. For MB, the adsorption process could be depicted primly by Langmuir function, while for MV, the equilibrium data agree well with all of the Langmuir, Freundlich, and D–R models. The Gibbs free energy (ΔG0), enthalpy change (ΔH0), and entropy change (ΔS0) for MB were all below zero, which indicated the adsorption was spontaneous and exothermic process; while for MV, the negative ΔG0 value and positive ΔH0 value imply that its adsorption process is...

3D sandwich-like frameworks constructed from silver chains: synthesis and crystal structures of six silver(I) coordination complexes

The reaction of AgNO3 with combinations of 4,4′-bipyridine (bpy), 1,2-di(4-pyridyl)ethane (dpe), 1,3-bis(4-pyridyl)propane (bpp), succinic acid (H2su), terephthalic acid (H2tp), 2,2′-diphenylaminedicarboxylic acid (H2dpadc), and naphthaleneacetic acid (Hnaa) in aqueous alcohol at room temperature produces block-like crystals of [Ag3(bpy)3](su)·10H2O, [Ag2(bpy)2](tp)·6H2O, [Ag2(dpe)2(H2O)2](dpadc)·H2O, [Ag6(dpe)6(H2O)4](tp)3·12H2O, [Ag(bpp)](naa), and [Ag2(bpp)2](dpadc)·6H2O. All six compounds consist of 1D infinite silver-bpy/dpe/bpp cationic chains, interspersed with organic carboxylate anions that provide charge compensation in the crystal structures. The lattice water molecules are situated among the framework of the crystal structure and show rich hydrogen-bonding interactions {except for [Ag(bpp)](naa)}, which help to orientate of the organic carboxylate anions in the crystal packing.

Dissolved organic matter in urban stormwater runoff at three typical regions in Beijing: chemical composition, structural characterization and source identification

In this work, DOM was extracted from urban stormwater runoff samples collected at three typical regions (business, residential and campus regions) in Beijing, China. A comparison between the chemical characteristics of DOM extracted from these three regions was performed using UV-visible spectrometry (UV-vis), excitation–emission matrix (EEM) fluorescence, proton nuclear magnetic resonance spectroscopy (1H NMR) and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS). The UV-vis and EEM spectra revealed that the DOM in stormwater runoff samples mainly contained UV humic-like (peak A) compositions with higher molecular weights. 1H NMR analysis indicated that the DOM of the three regions contained a similar distribution of functional groups, which mainly consisted of aliphatic chains and aromatic components with carbonyl, hydroxyl or alkyl terminal groups. And the UHPLC-Q-TOF-MS demonstrated the identification and characterization of possible compounds existing in the DOM. Further studies should focus on the interactive relationship between DOM and the co-existing contaminants (heavy metals and some typical organic pollutants) in stormwater runoff.

Three silver complexes constructed from organic carboxylic acid and 1,2-bis(4-pyridyl)ethane ligands: syntheses, crystal structures, and luminescent properties

Three silver-based complexes, namely [Ag2(bpa)2](Brtp)·6H2O (1), [Ag3(bpa)3](Hdcdcpb)·9H2O (2), and [Ag2(bpa)2(oa)]·2H2O (3), were synthesized via the reactions of AgNO3, 1,2-bis(4-pyridyl)ethane (bpa), and 2-bromoterephthalic acid (H2Brtp), 2,3-dicarboxyl-(2′,3′-dicarboxylazophenyl)benzene (H4dcdcpb) or 4,4′-oxybisbenzoic acid (H2oa) in aqueous alcohol/ammonia solution at room temperature. Complexes 1 and 2 consist of 1D infinite cationic [Ag(bpa)]nn+ chains, interspersed with non-coordinated and completely deprotonated Brtp2− or partly deprotonated Hdcdcpb3− anions acting as discrete counter-ions to balance the charge. The lattice water molecules are situated among the framework of the crystal structure and show rich hydrogen-bonding interactions, while the presence of Ag…N and Ag…Ag contacts strengthens the frameworks. Complex 3 consists of 2D neutral [Ag2(bpa)2(oa)] in which the completely deprotonated oa2− units both act as bidentate ligands and as counter-ions. All three complexes exhibit luminescent properties, which can be assigned to ligand-to-metal charge transfer and Ag…Ag interactions.

Three coordination compounds of cobalt with organic carboxylic acids and 1,10-phenanthroline as ligands: syntheses, structures and photocatalytic properties

AbstractnThree cobalt-based coordination compounds, [Co2(phen)4(H2qptb)](H3qptb)2 (1), [Co2(phen)4(H2dczpb)2]·5H2O (2) and [Co2(phen)4(H2odpa)2(H2O)2]·2H2O (3), were obtained from mixtures of quaterphenyl-4,2″,5″,4′-tetracarboxylic acid (H4qptb), 3,4-dicarboxyl-(3′,4′-dicarboxylazophenyl) benzene (H2dczpb), 4,4′-oxydiphthalic acid (H2odpa), along with 1,10-phenanthroline (phen) and cobalt salts by hydrothermal synthesis. Single-crystal X-ray diffraction reveals that complexes 1–3 contain [Co2(phen)4(L)] units, further joined into 3D frameworks via hydrogen-bonding interactions. All three complexes display considerable thermal stability and exhibit selective absorption in the ultraviolet region, as shown by thermogravimetric analysis and UV–Vis diffuse reflectance spectroscopy, respectively. Complex 1 mediates efficient photocatalytic degradation of methylene blue under UV irradiation.

Interactions between copper(II) and DOM in the urban stormwater runoff: modeling and characterizations

ABSTRACT Dissolved organic matter (DOM) can strongly interact with both organic and inorganic contaminants to influence their transportation, transformation, bioavailability, toxicity and even their ultimate fate. Within this work, DOM was extracted from urban stormwater runoff samples collected from a regular sampling site of a typical residential area in Beijing, China. Copper(II) ions were selected as model to investigate the interactions between DOM and typical heavy metals. Both ultraviolet (UV) absorbance and fluorescence titration methods were introduced to determine the complex capacities (CL) and conditional stability constants (log KM) of bonding between DOM and copper (II) ions, which revealed that the values of CL were 85.62 and 87.23u2005μmolu2005mg−1 and the log KM values were 5.37 and 5.48, respectively. The results suggested the successful complexation between DOM and copper(II) ions. Furthermore, morphology of the DOM binding to copper(II) ions was confirmed by both energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS), which can facilitate to clarify the corresponding mechanism. The Cu 2p3/2 peak at 933.7u2005eV and the characteristic shake-up peaks of Cu–O were found in the XPS spectra, implying that copper(II) ions might coordinate with hydroxyl (aliphatic or phenolic) or carboxyl groups. With these profitable results, it can be concluded that DOM in urban stormwater runoff has a strong binding affinity with copper(II) ions, which may further lead to potentially significant influence on their migration and transformation.