Hailian Xiao

Polyethylenimine modified magnetic graphene oxide nanocomposites for Cu2+ removal

Fe3O4 nanoparticles were synthesized on graphene oxide (GO), then mixed with polyethylenimine to obtain GO/Fe3O4/PEI nanocomposites. Due to the high surface area of GO, superparamagnetism of Fe3O4, and excellent complex ability of PEI, the nanocomposites showed extremely high Cu2+ removal efficiency. The Cu2+ removal capacity was 157 mg g−1, which is higher than most reported results. The adsorption kinetics could be best described by a pseudo-second-order model. Moreover, GO/Fe3O4/PEI nanocomposites could be easily recycled by magnetic separation. After five cycles, the removal efficiency remained 84%.

Synthesis, characterization and nonlinear optical effects of M4(µ4-O) core complexes with large two-photon absorption cross-section

Four tetranuclear 2-mercaptobenzothiazole cluster compounds [M4O(MBT)6] (M = Fe, Co, Ni, Cu; MBT = 2-mercaptobenzhothiazole) were synthesized and characterized by elemental analyses, IR and UV–vis spectra, and single crystal X-ray crystallography. The crystal structures of [M4O(MBT)6] (M = Fe, Co, Ni) confirm that the four metal(II) atoms locate four capsheaves of a tetrahedral skeletal structure and a tetracoordinate O2− as an interstitial atom occupies the centre position of this tetrahedron. The metal atoms all possess slightly distorted tetrahedral geometry. The thermal gravimetry data indicate that these clusters all have good thermal stability. The nonlinear absorption of four cluster solutions (in DMF) were measured by open-aperture Z-scan technique at a 532 nm wavelength. The results of Z-scan experiments show that these clusters all have remarkable and very strong nonlinear optical absorption effects. The largest two-photon absorption cross-section is 172880 GM for cluster [Fe4O(MBT)6].

Structure of the adduct of bis(O,O′-diisopropyldithiophosphato) metal with pyridine: Ni[(iPrO)2PS2]2(py)2 and Cd[(iPrO)2PS2]2 (py)2(py = pyridine)

The crystal and molecular structures of the complex of [Ni{(iPrO)2dtp}2(py)2] and [Cd{(iPrO)2dtp}2(py)2] (dtp = dithiophosphate, py = pyridine) have been determined by X-ray crystallography. They are isomorphous. The crystal structures are very similar and consist of discrete molecules of [Ni{(iPrO)2dtp}2(py)2] and [Cd{(iPrO)2dtp}2(py)2], respectively. They both crystallize in the monoclinic system, space group P21/c, the former with lattice parameters a = 6.489(1) Å, b = 14.830(3) Å, c = 16.386(3) Å, β = 99.74(3), and Z = 2; the latter with a = 6.461(3) Å, b = 14.583(4) Å, c = 17.433(4) Å, β = 99.55(3)°, and Z = 2. They all display distorted octahedral geometry around the central metal atom. In the complexes, two O,O′-diisopropyl dithiophosphate ions act as bidentate ligands with their S atoms coordinated to metal. Each forms a four-membered chelate ring in the equatorial plane. The N atoms from two pyridine ligands are axially coordinated to the metal atom. The Ni–S bond distances are 2.5137(10) and 2.5386(9) Å, and the Ni–N bond distances are 2.127(3) Å. The Cd–S(1) and Cd–S(2) bond distance are 2.694(1) and 2.704(1) Å, respectively, and the Cd–N bond distances are 2.399(3) Å. The IR spectra data is in agreement with the structural data.

Hydrogenation of o-chloronitrobenzene to o-chloroaniline over a Pt/γ-Fe2O3 catalyst under ambient conditions

Supported Pt nanocatalysts with controlled particle size and size distribution were prepared by immobilizing Pt colloids on different iron oxide supports (γ-Fe2O3, Fe3O4, Fe2O3) via physical adsorption. These catalysts were used to catalyze the liquid phase hydrogenation of o-chloronitrobenzene (o-CNB) to o-chloroaniline (o-CAN) under mild reaction conditions (298 K, 0.1 MPa). The Pt/γ-Fe2O3 exhibited higher catalytic selectivity and activity than other similar works (selectivity = 99.9%, activity = 0.20 molo-CNB/(molPt s)). The stability of the Pt/γ-Fe2O3 was investigated, and the result showed that higher drying temperature could increase the stability of the catalyst.

Crystal Structure and Characterization of the Dinuclear Cd(II) Complex [Cd(H2O)2(ο-HOC6H4COO)2]2

The structure of a new binuclear cadmium (II) complex, [Cd(H2O)2(Sal)2]2 (Sal= salicylate), has been determined by X-ray crystallography. It was also characterized by elemental analysis, its IR spectrum and thermogravimetric-differential scanning calorimetry (TG-DSC). It crystallizes in the monoclinic system, space group P2(1)/c, with lattice parameters a = 15.742(3) A, b = 12.451(3) A, c = 7.7225(15) A, beta = 96.07(3)degrees and Z = 4. Two cadmium (II) ions are bridged by two mu(2)-carboxy oxygen atoms. Each cadmium atom lies in a distorted capped octahedron coordination geometry. The thermal gravimetry (TG) data indicate that there are four discrete decomposition steps with two endothermic peaks and one exothermic peak. The final thermal decomposition product is CdO.

Synthesis, crystal structure and thermal stability of bis(1,10-phenanthroline) cobalt(II) cyanide ethanol solvate dihydrate

The compound [Co(phen)2(CN)2]·EtOH·2H2O was obtained by reaction of Co(CN)2 and 1,10-phenanthroline (phen) in 95% EtOH solution and characterized using IR and UV spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA) and X-ray crystallography. The deep-brown crystal is triclinic, space group P , with lattice parameters a = 10.356(2), b = 10.505(2), c = 12.148(2) Å, α = 79.19(3), β = 79.68(3), γ = 86.71(3)° and Z = 2. The compound contains a six-coordinate cobalt atom chelated by two phen ligands and two cyanide anions in a cis arrangement. One ethanol solvate molecule and two water molecules complete the crystal structure. In the solid state, the title compound forms a network structure through hydrogen bonds. Intermolecular hydrogen bonds connect the [Co(phen)2(CN)2], ethanol and H2O moieties. TG data indicate that thermal decomposition of the compound takes place in four steps, and the final product of thermal decomposition is CoC2. Elemental analysis, IR and UV spectra are in agreement with the structural data.

2-Benzoyl-N-phenyl-2-(1,2,4-triazol-1-yl)­thio­acet­amide and 2-(4-methoxy­benzoyl)-N-phenyl-2-(1,2,4-triazol-1-yl)­thio­acet­amide

In the two title compounds, C17H14N4OS, (I), and C18H16N4O2S, (II), the dihedral angles between the planes of the triazole and N-phenyl rings and the plane of five of the atoms that link these two rings are 63.5 (8) and 73.2 (6) degrees for (I), and 65.1 (1) and 72.1 (3) degrees for (II), respectively. There are some inter- and intramolecular interactions in the crystal structure.

Influence of Metal Ions on the Hydrogenation of Chlorobenzene Over Polymer-Stabilized Platinum Nanoparticles

The effect of metal ions on the hydrogenation of chlorobenzene over poly(vinylpyrrolidone)-stabilized platinum (PVP-Pt) colloidal catalysts was studied in methanol at 298 K and atmospheric pressure. It showed that some metal cations significantly affected the catalytic performances of the colloidal nanocatalysts. Almost all the metal cations studied decreased both the activity and the selectivity to cyclohexane, which might be due to the electron-deficient state of the surface Pt atoms resulting from the adsorbed metal ions. It is therefore essential to remove some metal ions, especially Sn2+, Cu2+, Zn2+, and Mn2+ from wastewaters for efficient catalytic hydrodechlorination.

Synthesis, structures and thermal properties of three crystalline polymorphs of the bis(n-phenylmethylbenzimidazole-n) dichloro cobalt(II) complex CoCl2(C7H5N2CH2Ph)2

Three polymorphic, crystalline specimens of the bis(N-phenylmethylbenzimidazole-N)dichloro cobalt(II) complex CoCl2(C7H5N2CH2Ph)2 have been obtained from different solvents and their structures determined by X-ray diffraction. X-ray analysis revealed that the three compounds have the same composition; however, details of their molecular structure differ significantly. The α-form is triclinic, space group , with lattice parameters a = 10.396(2), b = 10.439(2), c = 13.665(3) Å, α = 90.13(3), β = 110.15(3), γ = 110.46(3)°; both the β- and γ-forms crystallize in the monoclinic space group P21/c, with lattice parameters a = 12.884(3), b = 9.612(2), c = 21.761(7) Å, β = 108.02(3)° for the β-form and a = 7.357(2), b = 18.337(4), c = 19.572(5) Å, β = 107.46(3)° for the γ-form. In all three cases, the asymmetric unit consists of [CoCl2(C7H5N2CH2Ph)2] molecules. The geometry of their CoCl2N2 chromophore is a distorted tetrahedron. Thermogravimetric analysis (TGA) indicates that they have different thermal stabilities and give rise to different resting residues. The electronic and IR spectra were also investigated. Analysis of the extent to which the stereochemistry of the constituent molecules in polymorphs A, B and C differ was examined using the program MATCHIT. There are major differences in the atomic positions of chemically related atoms that are not related to space group differences. The differences are caused by significant torsional motions of the flexible groups that seem to be caused by changes in the solvent media from which the crystals were obtained. Thus, the solvent cage of the parent solutions seems to be, at least partially, responsible for the incidence of crystalline polymorphism.

Structure of tetra(β-propiophenone-1,2,4,triazole-N4) dichloro metal hexahydrate complex: [MCl2(C2H2N3CH2CH2COPh)4]⋅6H2O (M = Ni, Co)

The crystal and molecular structures of the complexes of [NiCl2(N4-trzCH2CH2 COPh)4]⋅6H2O and [CoCl2(N4-trzCH2CH2COPh)4]⋅ 6H2O (trz = 1,2,4-triazole) have been determined by X-ray crystallography. They are isomorphous. The crystal structures are very similar. They both crystallize in the monoclinic system, space group P21/c, Z = 4; the former with lattice parameters a = 8.0391(2), b = 10.8215(2), c = 29.0133(2) Å, β = 94.792(1)°; the latter with a = 8.039(2), b = 10.822(2), c = 29.013(6) Å, β = 94.79(3)°. They all display almost perfect octahedral coordination geometry around the central metal atom. Each metal atom is coordinated by four N atoms of triazole from four β-propiophenone-1,2,4-triazole ligands and two chloride anions in a trans arrangement. In addition to the coordinating metal complex, there are six uncoordinated water molecules, which complete the crystal structure. In the solid state, the title two compounds form three dimensional network structures through hydrogen bonds. The intermolecular hydrogen bonds connect the [MCl2(C2H2N3CH2CH2COPh)4] and H2O moieties.