From Layered Double Hydroxide to Spinel Nanostructures: Facile Synthesis and Characterization of Nanoplatelets and Nanorods

Mg−Al spinel (MgAl2O4) nanorods and nanoplatelets transformed from Mg−Al layered double hydroxide (Mg−Al-LDHs) were synthesized via a combined hydrothermal method and calcination route using Al(NO3)·9H2O and Mg(NO3)2·6H2O as raw materials. The nanorods and nanoplatelets were characterized by means of physical techniques, including powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microcopy (HRTEM), selected-area electron diffraction (SAED), Fourier transform infrared spectra (FT-IR), thermogravimetric (TG), and nitrogen adsorption−desorption isotherms. XRD patterns reveal that the Mg−Al-LDHs nanostructures were obtained under a hydrothermal reaction temperature of 200 °C and Mg−Al spinel nanostructures were fabricated via calcination of the Mg−Al-LDHs nanostructures at 750 °C. It can be seen from TEM that the sizes of the Mg−Al-LDHs nanoplatelets were about 20−40 nm and the diameters of the MgAl2O4 nanorods were ca. 6 nm. The HRTEM images indicate that the crystal lattice spaces of the MgAl2O4 nanorods and nanoplatelets are 0.282 and 0.287 nm, respectively

Self-Assembly of a CsCl-like 3D Supramolecular Network from [Zn₆(HL)₆(H₂L)₆]⁶⁺ Metallamacrocycles and (H₂O)₂₀ Clusters (H₂L = 4-(2-Pyridyl)-6-(4-pyridyl)-2-aminopyrimidine)

The reaction of Zn(NO3)2·6H2O with multifunctional ligand 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (H2L) leads to a circular hexanuclear zinc complex [Zn6(HL)6(H2L)6](NO3)6·26H2O (1), confirmed by single-crystal X-ray diffraction. In the [Zn6(HL)6(H2L)6]6+ cation, six zinc centers are arranged in a chairlike conformation and 12 ligands fulfill bridging and terminal functions, respectively. The particular interest of complex 1 is the formation of a unique water cluster (H2O)26 composed of a clathrate (H2O)20 core and six dangling water molecules, and the clathrate (H2O)20 core is structurally similar to the famous “Bucky water” (H2O)20. Furthermore, the water molecules and the nitrate ions are assembled into an interesting negative three-dimensional (3D) framework through hydrogen bonds, and the [Zn6(HL)6(H2L)6]6+ cations just locate in the cavities of the anionic 3D network. To gain insight into the stability of (H2O)20 observed in complex 1, we isolate the water cluster from its environments and compare its stability with “Bucky water” (H2O)20 by a theoretical calculation method. Complex 1 displays room temperature photoluminescence

Self-Assembly of a CsCl-like 3D Supramolecular Network from [Zn₆(HL)₆(H₂L)₆]⁶⁺ Metallamacrocycles and (H₂O)₂₀ Clusters (H₂L = 4-(2-Pyridyl)-6-(4-pyridyl)-2-aminopyrimidine)

The reaction of Zn(NO3)2·6H2O with multifunctional ligand 4-(2-pyridyl)-6-(4-pyridyl)-2-aminopyrimidine (H2L) leads to a circular hexanuclear zinc complex [Zn6(HL)6(H2L)6](NO3)6·26H2O (1), confirmed by single-crystal X-ray diffraction. In the [Zn6(HL)6(H2L)6]6+ cation, six zinc centers are arranged in a chairlike conformation and 12 ligands fulfill bridging and terminal functions, respectively. The particular interest of complex 1 is the formation of a unique water cluster (H2O)26 composed of a clathrate (H2O)20 core and six dangling water molecules, and the clathrate (H2O)20 core is structurally similar to the famous “Bucky water” (H2O)20. Furthermore, the water molecules and the nitrate ions are assembled into an interesting negative three-dimensional (3D) framework through hydrogen bonds, and the [Zn6(HL)6(H2L)6]6+ cations just locate in the cavities of the anionic 3D network. To gain insight into the stability of (H2O)20 observed in complex 1, we isolate the water cluster from its environments and compare its stability with “Bucky water” (H2O)20 by a theoretical calculation method. Complex 1 displays room temperature photoluminescence

Synthesis and Photoluminescent Properties of Strontium Tungstate Nanostructures

Strontium tungstate nanoparticles with diameters of 40−50 nm, nanopeanuts with diameters of 100−150 nm, and nanorods with a rough surface were controllably synthesized by a solvothermal-mediated microemulsion method. Various comparison experiments showed that several experimental parameters, such as the molar ratio (w) between water and CTAB and the concentration of reactants, played important roles for the morphological control of Sr(NO3)2 nanostructures. When the concentration of the Sr(NO3)2 aqueous solution was kept at 0.3 M, the morphology of the as-synthesized products elongated from nanospheres, to nanopeanuts, and to nanorods with the increase of the w value. A possible mechanism is proposed for the selective formation of the different morphologies. The SrWO4 samples with different morphologies exhibited different photoluminescent properties. X-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, and field-emission scanning electron microscopey were used to characterize these products