Xiao-Han Gao

Molar heat capacity and thermodynamic properties of crystalline Eu(C 2 H 5 O 2 N) 2 Cl 3 ·3H 2 O

A complex of europium hydrochloric acid coordinated with 2-aminoacetic acid (C2H5O2N), Eu(C2H5O2N)2Cl3·3H2O was synthesized and characterized by IR and elements analysis. The heat capacities of the complex was measured with an automatic adiabatic calorimeter, and the thermodynamic functions [HTxa0−xa0H298.15] and [STxa0−xa0S298.15] were derived in the temperature range from 80 to 340xa0K with temperature interval of 5xa0K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis and differential scan calorimeter (DSC).

Direct hydroxylation of benzene to phenol with molecular oxygen over vanadium oxide nanospheres and study of its mechanism

Direct hydroxylation of benzene to phenol using molecular oxygen is a green route with high atom economy but still a great challenge when compared with the existing method of production. The activation of oxygen is necessary and reductive agents were used to activate dioxygen in a so-called “reductive activation” process. Here, nano vanadium oxides that consist mainly of low valence vanadium to activate dioxygen were prepared under different conditions via a hydrothermal method. Under the optimized conditions, an excellent phenol selectivity of 96.3% with benzene conversion of 4.2% was achieved over the VOC2O4–N-5 without reductive agents. Characterizations revealed that VOC2O4–N-5 was composed of a mesoporous nanosphere structure with medium strong acid sites and low valence vanadium species. A mechanism was proposed as follows: dioxygen was activated by low valence vanadium in VOC2O4–N-5 to produce the active oxygen species which oxidized acetic acid to peracetic acid. Then the active oxygen species was subsequently transferred from peracetic acid to benzene and inserted into the C–H bond to give phenol.

Molar heat capacity and thermodynamic properties of Lu(C5H9NO4)(C3H4N2)6(ClO4)3·5HClO4·10H2O

A complex of Lutetium perchloric acid coordinated with l-glutaminic acid (C5H9NO4) and imidazole (C3H4N2), Lu(C5H9NO4)(C3H4N2)6(ClO4)3·5HClO4·10H2O was synthesized and characterized. Thermodynamic properties of the complex were studied with an adiabatic calorimeter (AC) from 80 to 390xa0K and differential scanning calorimetry (DSC) from 100 to 300xa0K. Two thermal abnormalities were discovered at 220.34 and 248.47xa0K, which were deduced to be phase transitions. One was interpreted as a freezing-in phenomenon of the reorientational motion of ClO4− ions and the other was attributed to the orientational order/disorder process of ClO4− ions. The low-temperature molar heat capacities were measured by AC and the thermodynamic functions [HTxa0−xa0H298.15] and [STxa0−xa0S298.15] were derived in the temperature range from 80 to 390xa0K with temperature interval of 5xa0K. Thermal decomposition behavior of the complex was studied by thermogravimetric analysis and DSC.

The synthesis, structure, and fluorescence properties of two heptanuclear coordination compounds containing trigonal prismatic [LnCu6(μ-OH)3(Gly)6Im6]6+ cations (Ln: Eu, Sm)

Two heptanuclear trigonal prismatic polyhedra, [EuCu6(μ-OH)3(Gly)6Im6](ClO4)6·3H2O and [SmCu6(μ-OH)3(Gly)6Im6](ClO4)6·3H2O were synthesized through self-assembly of Eu3+(Sm3+), Cu2+, glycine, and imidazole in aqueous solution and characterized by X-ray single crystal diffraction. Both complexes crystallize in the rhombohedral R3 space group (a = b = 15.8673 Å, c = 23.4038 Å, V = 5103.0(6) Å3, Z = 3) and (a = b = 15.8749 Å, c = 23.455 Å, V = 5119.1(8) Å3, Z = 3). In the clusters, Sm3+ and Eu3+ ions are situated in the center of a prism formed by six copper ions and coordinate to nine oxygens with a tricapped trigonal prismatic coordination polyhedron. Six glycinato ligands and six imidazole terminal ligands (each coordinates to one Cu2+) construct the cluster. The fluorescent excitation and emission spectra showed that the complexes have strong ligand-based fluorescence.

Low-temperature molar heat capacities, thermodynamic properties and crystal structure of Cu(C3N2H4)4(ClO4)2

A complex of copper perchlorate coordinated with imidazole Cu(C3N2H4)4(ClO4)2 was synthesized and characterized by X-ray single-crystal diffraction. The complex is centrosymmetric in the monoclinic P2(1)/c space group. The low-temperature molar heat capacities and thermodynamic properties of the complex were studied with adiabatic calorimetry (AC). The thermodynamic functions [HT–H298.15] and [ST–S298.15] were derived in the temperature range from 80 to 370xa0K with temperature interval of 5xa0K. Thermal decomposition behavior of the complex in nitrogen atmosphere was studied by thermogravimetric (TG) analysis and differential scanning calorimetry (DSC). The mechanism of the decomposition was deduced to be the breaking up the two Cl–O bonds of the Cl–O–Cu and the Cu–N bonds of the imidazole rings in succession.

Structures, Magnetic and Thermodynamic Properties of a 3d–4f Mixed Metal Cluster [ErZn6(μ3-O)3(μ3-C2H4NO2)6(H2O)9]6+

A heterometallic 3d–4f complex with hepta-nuclear hexagonal cluster, [ErZn6(μ3-O)3(μ3-C2H4NO2)6(H2O)9]6+ (C2H4NO2u2009=u2009glycine) was synthesized and characterized. The cluster belongs to hexagonal crystal system. It crystallizes in the P-6 space group. In each cluster, Er3+ ion is in the center of a prism, which is composed of six zinc atoms. Er3+ ion coordinates to nine oxygen atoms. Each glycine ligand chelates to two Zn2+ and one Er3+ ions using a μ3-coordination mode. Fluorescent, thermodynamic and magnetic studies of the cluster were performed. The complex does not show single molecule magnet behavior.