Ji-Xiao Wang

Triazine–polycarboxylic acid complexes: synthesis, structure and photocatalytic activity

Four novel transition metal complexes, [Zn2(Bpz*eaT)2(HBTC)2]·(CH3OH)3 (1), [Co(Bpz*eaT)(HBTC)]·(CH3CH2OH)0.5·(H2O)0.5 (2), [Zn(Bpz*eaT)(H2BTA)(pz*H)] (3) and [Cu4(Mpz*T-O2)4(BTA)(H2O)8]·4H2O (4) (Bpz*eaT, 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-diethylamino-1,3,5-triazine; Mpz*T-O2, 6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4(1H,3H)-dione; pz*H, 3,5-dimethyl-1H-pyrazole; H3BTC, benzene-1,3,5-tricarboxylic acid; and H4BTA, 1,2,4,5-benzenetetracarboxylic acid), were synthesized by the reaction of metal salts (ZnSO4·7H2O, CoCl2·6H2O or CuCl2·2H2O), pincer N-heterocyclic triazine derivatives and aromatic polycarboxylate ligands. All the complexes were characterized by elemental analysis, IR spectroscopy, UV-vis spectroscopy, thermal gravimetric analysis and single-crystal X-ray diffraction. Structural analysis reveals that complexes 1 and 2 are 2-D layers and complex 4 is a 3-D network structure with hydrogen bonding. In addition, the photocatalytic performances of complexes 1–4 were studied under UV irradiation at room temperature and their photocatalytic activity was also discussed. The result showed that complex 1 possessed higher photocatalytic activity.

Experimental and theoretical investigations of copper (I/II) complexes with triazine-pyrazole derivatives as ligands and their in situ C-N bond cleavage.

Two copper complexes, Cu(SCN)(Mpz(∗)T-(EtO)2) (1) (Mpz(∗)T-(EtO)2=L3) and CuCl(H2O)(Mpz(∗)T-O2) (2) (Mpz(∗)T-O2=L4) were synthesized by the reaction of 2,4,6-tri(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine (L1) or 2,4,6-tri(1H-pyrazol-1-yl)-1,3,5-triazine (L2) with CuCl2·2H2O in anhydrous ethanol and methanol, respectively. The complexes were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single crystal X-ray diffraction and X-ray powder diffraction. The structural characterizations and quantum mechanical calculations of the two complexes were analyzed in detail. It was found that an in site reaction occurred during the synthesis process of complexes 1 and 2, likely due to catalytic property of copper ions which leads to the C-N bond cleavage to generate new organic species, namely, Mpz(∗)T-(EtO)2 (L3) and Mpz(∗)T-O2 (L4).

Design, synthesis and structure of uranyl coordination polymers from 2-D layer to 3-D network structure

Solvothermal reaction of uranyl acetate and succinic acid in DMF resulted in formation of three uranyl coordination polymers, [(UO2)4(μ2-OH)7(OH)6]·2(H2O)·(H3O)·4NH2(CH3)2 (1), [(UO2)(μ2-OH)(OH)3]·2NH2(CH3)2] (2), and [(DMF)2(UO2)(μ2-OH)4(UO2))] (3). The products were characterized by elemental analysis, IR spectroscopy, X-ray single crystal, and powder diffraction. Structural analysis shows that 1 is a layer, 2 and 3 are 3-D network structures.

Structure, Characterization and Photocatalytic Activity of a Series of Well-Established Covalent Heterojunction Coordination Polymers

Six novel coordination polymers {Co(HCOO)2(4,4′-bipy)}n (1), {[Ni(4,4′-bipy)(OH)2(H2O)2]·suc·2H2O}n (2), {Ni(HCOO)2(4,4′-bipy)}n (3), {Zn(HCOO)2(4,4′-bipy)}n (4), {Cu(HCOO)2(4,4′-bipy)}n (5) and {[Cu(ox)(2,2′-bipy)]·2H2O}n (6) (suc succinic acid, ox oxalic cid) based on pyridine derivatives and carboxylates as ligands were designed and synthesized. The coordination polymers were characterized by elemental analysis, IR and UV–Vis spectra, powder X-ray diffraction, the thermo gravimetric analyses and single-crystal diffraction analysis. The structure analysis showed that the central metal atoms in coordination polymers 1, 2, 3, 4 and 6 all were six-coordination modes, forming distorted octahedron geometries. Cu atom in the coordination polymer 5 was four-coordination mode, forming square planar coordination geometry. While in the coordination polymers 1, 3 and 4, two metal centers were connected by bridging coordination fashions of formic acid ligand, forming a three-dimensional network structure, and in the coordination polymer 6, the two metal centers were connected by bridging coordination fashions of oxalic acid ligand, forming one-dimensional chain. In addition, the photocatalytic activity of a series of covalent heterojunction coordination polymers was studied.

Synthesis, structures, and catalytic studies of new copper(II) complexes with arene-linked pyrazolyl methane ligands

Two new copper complexes, [Cu2(L1)(dipic)2(H2O)2]⋅2H2O (1) and [Cu2(L2)(dipic)2(H2O)2]⋅3H2O (2) (L1 = 1,4-bis((1H-pyrazol-1-yl)methyl)benzene; L2 = 1,4-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzene; and H2dipic = 2,6-pyridinedicarboxylic acid), were synthesized by the reaction of copper salt, arene-linked pyrazolyl methane ligands, and 2,6-pyridinedicarboxylic acid in 95% C2H5OH. They were characterized by elemental analysis, IR, UV–vis, single-crystal X-ray diffraction analysis, X-ray powder diffraction, and thermogravimetric analysis. We explored the application of the copper complexes in bromination reactions; the complexes exhibited bromination catalytic activity in single-pot reaction for the conversion of phenol red into bromophenol blue. A feasible bromination reaction mechanism of copper complexes was proposed. Graphical abstract Two new copper complexes, [Cu2(L1)(dipic)2(H2O)2]⋅2H2O (1) and [Cu2(L2)(dipic)2(H2O)2]·3H2O (2) (L1 = 1,4-bis((1H-pyrazol-1-yl)methyl)benzene; L2 = 1,4-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzene; and H2dipic = 2,6-pyridinedicarboxylic acid), have been synthesized. The application of the copper complexes in bromination reaction was explored, and a mechanism was proposed.

A new metallate phase of V2O5 crystalline microstructure achieved in a facile route: synthesis, characterization, and measurement in catalytic reactions.

Experiencing a series of complicated changes, abundant orange crystals of novel metallic phase of vanadium pentoxide were obtained by a mild chemical method, the formula of which is defined as [V3(μ3-O)2⋅(μ1-OH)⋅O5]⋅H2O. Differ from the synthesis methods of vanadium oxide published, we have adopted a simple solution method that mixed starting materials are refluxing in the system of ethanol-water under a relatively lower temperature. Symmetry of the crystals is Monoclinic, with cell unit dimensions: a=4.9978(10)Å, b=8.4273(17)Å, c=7.8669(16)Å, β=96.44(3)° and space group of P2₁/m. The structure of the complex was characterized by elemental analysis, IR, UV-vis spectroscopy and single-crystal diffraction analysis. Powder X-ray diffraction (PXRD) was used to detect the purity of the crystals, and crystal morphology was detected by the scanning electron microscope (SEM). In addition, in order to extend application of oxidovanadium complexes, bromination catalytic activity about the complex in a single-pot reaction of the conversion of phenol red to bromophenol blue in a mixed solution of H2O-DMF at a constant temperature of 30±0.5 °C with a buffer solution of NaH2PO4Na2HPO4 (pH=5.8) was evaluated firstly, indicating that the complex can be considered as a potential functional model of bromoperoxidase, in the meantime, we have conducted the bromination catalytic reaction to simulate and measure the changes in reaction process indirectly. Besides, catalytic oxidation activity of the complex is also evaluated in the oxidation of cyclohexane (Cy) and cyclopentane with hydrogen peroxide promoted under mild conditions, showing potential catalytic activity of the complex by comparing TON (total turnover number) ratios of CyO/CyOH (CyO is the abbreviation of cyclohexanone and CyOH represents cyclohexanol) in the oxidation results.