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The substitution reactions of M(CH 3CH 2CO 2) 2and Htza afford the crystalline precipitates of [Cd(tza) 2] ( 1), [Mn(tza) 2] ( 2), [Co(tza) 2] ( 3), and β-[Zn(tza) 2] ( 5). The recrystallization of 5leads to the formation of α-[Zn(tza) 2] ( 4). X-ray powder diffraction of 1− 5reveal that 1, 2, 3, and 5are allomers, but 4and 5are isomers, revealing the unprecedented structural transformation during the process of recrystallization. Compounds 1− 4have been characterized by X-ray single-crystal crystallography, IR, and magnetism analysis. Structural analyses and comparison of 1− 4detail the structural evolution of from β-[Zn(tza) 2] ( 5) to α-[Zn(tza) 2] ( 4) and possible driving force has been proposed. The interactions between the Mn IIions of 2have been observed as weakly antiferromagnetic. [ABSTRACT FROM AUTHOR]

Because porous metal oxides with controllable morphologies have been attracting much attention for their potential applications in the fields of adsorption/separation, sensing, energy storage, and conversion, it is highly desirable to prepare new morphology of metal oxides and investigate their performance. In this work, CuO particles with different shapes such as octahedron, sponge-like octahedron, and sphere have been synthesized through thermal decomposition of crystalline Cu(II)-organic frameworks (HKUST-1). The structure and morphology of as-prepared CuO particles have been fully characterized by the usage of XRD, XPS, SEM, and TEM. The gas-sensing behaviors of these CuO samples have been investigated and our results show that CuO-400 with spherical shape displays unprecedented high response (maximum value, 102) for triethylamine (TEA) at 100 ppm with a low detection limit of 5 ppm, a lower working temperature (230 °C), excellent reproducibility, and long-term stability. The highly sensing behavior of CuO-400 sphere might be due to its special structural factor with many open active sites for oxygen adsorption, which could react with TEA molecules more efficiently. Our results clearly suggest that porous CuO particles should be promising candidates for future practical application to detect TEA vapor at relatively low temperature. [ABSTRACT FROM AUTHOR]

Two new three-dimensional (3D) multinodal Cd(II)-organic frameworks, [Cd3(dccpa)(bipy)0.5(H2O)4]·5H2O (1) and [(CH3)2NH2]2[Cd11(dccpa)4(DMF)4(H2O)8]·4H2O (2) (H6dccpa = 3,4-di(3,5-dicarboxyl phenyl) phthalic acid, bipy = 4,4′-bipyridine), have been prepared and fully characterized. Compound 1 possesses a 3D neutral framework with a new (6,6,7)-connected topology based on a single trinuclear cluster, while 2 features a 3D anionic framework with a new (5,6,6,10)-connected topology containing mixed trinuclear and pentanuclear clusters. Remarkably, 1 and 2 show promising photocatalytic activities toward the degradation of rhodamine B and methyl blue, which suggests that different kinds of cluster units may exert different impacts on the decomposition of organic dyes. [ABSTRACT FROM AUTHOR]

Amorphous calcium phosphate oftenforms as a precursor phase ina solution at sufficiently high supersaturation and pH, and then transformsto the thermodynamically stable hydroxyapatite. The chemical composition,structure, and property of the amorphous phase are dependent on thestructure of its composing clusters. Based on the results from themeasurements of in situ Ca K-edge X-ray near-edge structure and exsitu X-ray diffraction, as well as the concomitant pH change in thereaction process, here we propose an improved model for the structureof “Posner’s cluster” and identify the threetypes of reactions that lead to the formation of amorphous calciumphosphate and its subsequent transition to crystalline hydroxyapatite. [ABSTRACT FROM AUTHOR]

In this contribution, we devote our effort to explore the effect of stoichiometry of the 4,4′-dipyridylsulfide (dps) ligand on the final structures in the ZnII-hfipbb binary system (H2hfipbb = 4,4′-(hexafluoroisopropylidene)bis(benzoic acid)). The solvothermal reaction of zinc acetate and H2hfipbb with the different stoichiometries of dps from 0.1 to 0.4 mmol has resulted in three new coordination polymers, [Zn(hfipbb)(H2hfipbb)0.5]n(1) and [Zn2(hfipbb)2(dps)(H2O)]n(2aand 2b). The structure determination reveals that complex 1displays a three-dimensional (3D) 2-fold parallel interpenetrating pillared-layer network with one-dimensional double left- and right-handed helical tubes. Complexes 2aand 2bare framework-isomeric as two unusual (3,4)-connected 3D coordination networks, i.e., a 4-nodal (7·82)(4·7·9)(72·84)(4·72·8·92) net and 2-fold interpenetrating (83)2(85·10) net. In addition, the properties of thermogravimetric analysis, X-ray powder diffraction, and photoluminescent behaviors of the complexes have been also discussed. [ABSTRACT FROM AUTHOR]