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Zhou Y.,Guangxi University | Zhou Y.,Guangxi University for Nationalities | Zhao W.-H.,Guangxi Research Institute of Chemical Industry | Wang J.,Guangxi University | And 5 more authors.
Bulletin of the Korean Chemical Society | Year: 2015

Four metal-organic coordination polymers, {[Cd2(BIBP)2(H2DTDA)2]n · 2(H2O)} (1), [Zn (BIBP) (H2TDA)2]n (2), [Cd2(BIBP)(H2TDA)2]n (3), and [Ni2(BIBP)2(H2DTDA)2(μ-O)]n, (4) [where BIBP = 4,4'-bis(1-imidazoly)biphenyl, H2TDA = [1,1':401"-terphen-yl]-3,3"-dicarboxylic acid, and H2DTDA = 2',5'-dimethyl-[1,1':4',1"-terphenyl]-3,3"-dicarboxylic acid] were hydrothermally synthesized and characterized by elemental analyses, IR, TG, luminescence, and single crystal X-ray diffraction. X-Ray diffraction analysis reveals that the four complexes exhibit new frameworks due to diverse coordination conformations. The different coordination modes of the ligands BIBP and two aromatic carboxylate acids play important roles in the construction of the final structure for the complexes. X-ray structure analysis reveals that 1, 2, and 4 are 3D coordination polymers, while complex 3 is a 2D network polymer. © 2015 Korean Chemical Society, Seoul & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang K.,Guangxi University | Wu X.,Guangxi University | Wu W.,Guangxi University | Wu W.,Universities Key Laboratory of Applied Chemistry Technology and Resource Development | And 3 more authors.
Journal of Thermal Analysis and Calorimetry | Year: 2015

A hierarchical rambutan-like MnCo2O4 precursor is synthesized by a co-precipitation method in water–ethanol at room temperature. After being calcined at 400 °C in air for 10 min with a heating rate of 1 °C min−1, the precursor MnCo2(C2O4)3·5.54H2O is transformed into the rambutan-like MnCo2O4 microspheres composed of end-connected nanorods, which has a large specific surface area (155 m2 g−1). When evaluated as adsorbent for methyl orange (MO), the rambutan-like MnCo2O4 microspheres show excellent adsorption ability for methyl orange. The adsorption capacity of methyl orange on rambutan-like MnCo2O4 is 185.14 mg g−1 under the conditions of initial MO concentration 12 mg L−1 and pH 2.09. Adsorption kinetics of methyl orange on rambutan-like MnCo2O4 follows the pseudo-second-order kinetic model. The values of adsorption activation energy Ea and enthalpy ΔH# are 5.71 ± 0.056 and 9.30 kJ mol−1, respectively. Methyl orange adsorption on rambutan-like MnCo2O4 is an endothermic and physical adsorption process. © 2015 Akadémiai Kiadó, Budapest, Hungary


Huang X.,Guangxi University | Wang M.,Guangxi University | Wang L.,Guangxi University | Wang J.,Guangxi University | Wang J.,Universities Key Laboratory of Applied Chemistry Technology and Resource Development
Journal of Organometallic Chemistry | Year: 2015

DFT studies on rhodium(III)-catalyzed alkenylation of 8-methyquinolines show that the activation of C(sp3)-H bond of 8-methylquinoline prefers to undergo four-membered ring process with free energy barrier of 29.8 kcal/mol, rather than six-membered ring process because of the electron-delocalized effect of oxygen atom to Rh center. The diphenylacetylene coordinates into the Rh center of the catalyst, in which Rh center tends to maintain 16e structure rather than 18e structure, and then inserts into the activated Rh-C bond with a free energy barrier of 21.2 kcal/mol. The binding of HOAc process is a premise for the catalyst regeneration, in which the Rh center directly accommodate HOAc instead of experiencing seven-membered rhodacycle proposed by the experiment. The catalyst was eliminated via a direct hydrogen transfer with an energy barrier of 12.8 kcal/mol, rather than Rh-mediated hydrogen transfer, which is attributed to the formation of unstable 20e species in the Rh-mediated process. The substituted effect follows the H < F < NMe2 trends, being consistent with its experimental results. © 2015 Elsevier B.V. All rights reserved.


Chen W.,Guangxi University | Zhou Y.,Guangxi University | Lu J.,Guangxi University | Huang X.,Guangxi Zhuang Autonomous Region Metallurgical Products Quality Supervision and Test Station | And 5 more authors.
Ceramics International | Year: 2016

Co-Mn ferrites with a nominal composition LixCo0.5Mn0.5-xFe2O4 (0.0≤x≤0.3) are prepared by calcining precursor oxalates in air. The effects of composition and calcination temperatures on their structure, morphology, and magnetic properties are studied. A high-crystallized LixCo0.5Mn0.5-xFe2O4 with a cubic structure is obtained when the precursor is calcined at 950 °C in air for 3 h. All the Li+ substituted Co-Mn ferrites exhibit typical spinel structure. Moreover, lattice parameters of LixCo0.5Mn0.5-xFe2O4 decrease and crystallite size increases with increasing Li+ content, leading to an increase of the specific saturation magnetization and a decrease of the coercive field and the magnetic anisotropy constant. © 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

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