Colloidal indium oxide (In2O3) nanoparticles 4 nm in diameter have been prepared by thermal decomposition of In(acac)3 (acac = acetylacetonate)/oleylamine (1:48 molar ratio) at 250 ℃. Nanoparticles 6 nm in diameter were obtained, when a 1:12 molar ratio of In(acac)3 and oleylamine was used for the nanoparticle preparation. Bigger nanoparticles 8 nm in diameter were obtained by using 6 nm nanoparticles as seeds (multiple additions of In(acac)3 into a reaction mixture containing 6 nm sized In2O3 nanoparticles). Nanoparticles are spherical and moderately monodispersed (\sigma \approx 10%) without any further size selection processes. The cubic crystalline nature of the In2O3 nanoparticles is indicated by electron diffraction, X-ray diffraction, and high-resolution transmission electron microscopic images of the nanoparticles. Photoluminescence spectroscopy of In2O3 nanoparticles shows strong emission maxima at 3.81 eV (325 nm) for 4 nm In2O3, 3.76 eV (330 nm) for 6 nm In2O3, and 3.73 eV (332 nm) for 8 nm In2O3, and thus are slightly blue-shifted (60 \sim 140 meV) as compared to 3.67 eV (338 nm) of the bulk In2O3, indicating that the prepared nanoparticles are in the quantum confinement regime. Colloidal, highly crystalline, monodisperse, and size-controlled Mn3O4 and MnO nanoparticles have been prepared by thermal decomposition of a single precursor Mn(acac)2 in oleylamine under an inert atmosphere in the presence and absence of small amount of water, respectively. Mn3O4 nanoparticles 10 nm in diameter have been prepared by thermal decomposition of Mn(acac)2/oleylamine (1:24 molar ratio) at 180 ℃. The particle size can be varied easily by a simple change in the reaction temperatures; smaller nanoparticles 6 nm in diameter were obtained at 150 ℃ and larger nanoparticles 15 nm in diameter were prepared at 250℃. MnO nanoparticles without contamination by Mn3O4 were prepared when 10 equiv of water was introduced to the reaction slurry of Mn(acac)2 in oleylamine (1:24 molar ratio). Again a simple change in the reaction temperatures resulted in variation of the MnO nanoparticle size: 11 nm particles (220℃, 9h), 17 nm particles (220℃, 3h and then 250℃, 6h), and 22 nm particles (250℃, 9h). Nanoparticles are moderately monodispersed (\sigma \approx 10%) without any further size selection processes. The tetragonal and cubic crystalline nature of the Mn3O4 and MnO nanoparticles, respectively, are indicated by electron diffraction, X-ray diffraction, and high-resolution transmission electron microscopic images of the nanoparticles. The three Mn3O4 nanoparticle samples showed ferromagnetic behaviors at low temperatures while they were paramagnetic at room temperature. Under zero-field cooling (ZFC) measurements at 100 Oe, the observed blocking temperatures TB were 36 K, 40 K, and 41 K for 6 nm, 10 nm, and 15 nm Mn3O4 nanoparticles, respectively. The three MnO nanoparticle samples showed ferromagnetic behaviors at low temperatures due to the noncompensated magnetic moment, but unusual size-dependency of magnetic properties was observed for MnO nanoparticles. Under ZFC measurements at 100 Oe, the observed blocking temperatures TB were 25 K, 18 K, and 10 K for 11 nm, 17 nm, and 22 nm MnO nanoparticles, respectively. A three-dimensional networked osmium nano-material (N-Os) was prepared by a thermal decomposition of Os3(CO)12 within mesopores of MCM-48. The highly crystalline nature and long-range ordered structure of N-Os are indicated by X-ray diffraction and high-resolution transmission electron microscopic images of the nano-material. A very high BET surface area of 126 \frac{m^2}{g} has been obtained for the N-Os from N2 adsorption isotherms. The novel N-Os species shows high catalytic activity and excellent reusability in the oxidation reactions of unsaturated organic compounds under mild conditions.
