Synthesis and characterization of monodispersed, oleic acid/oleylamine stabilized silver nanospheres in organic medium.

One-pot synthesis of spherical silver nanoparticles with excellent monodispersity in organic medium is presented in this account. Thermal decomposition of organometallic precursor, (hfac)Ag(PMe3) in the presence of oleic acid and oleylamine in o-xylene provides monodispersed silver nanospheres with the average diameters ranging from 15 to 18 nm and the deviations less than 7%. Characterization of the resulting silver nanoparticles by TEM analyses and UV-visible spectra demonstrated a narrow size distribution of the particles prepared in this study comparable to or better than those made by other synthesis methods.

Size-, and shape-selective synthesis of platinum nanoparticles from Pt(beta-diketonate)2 complexes in organic media.

Preparation of platinum nanoparticles from two beta-diketonate complexes of platinum, Pt(hfac)2 and Pt(acac)2 (hfac: hexafluoroacetylacetonate, acac: acetylacetonate) in organic media will be presented in the contribution. Nearly spherical, well-dispersed platinum nanoparticles were fabricated by thermally-induced reduction of Pt(hfac)2 in the presence of teraalkylammonium salts as the stabilizing agents in several organic solvents. Particle sizes ranging from 9 to 15 nm can be controlled by variation of the surfactant, the concentrations of precursor and surfactant, as well as reaction temperature. Heating the solution of Pt(acac)2 complex in 1-octanol at appropriate temperatures provided the platinum nanocubes and the influence of reaction temperature on the particle shape was investigated.

Solvent-dependent, low-temperature solution phase synthesis of FePt nanowires.

Preparation of FePt nanowires by thermal decomposition of the solution mixture of equimolar Fe(CO)5 and Pt(acac)2 in n-octylamine will be presented in this account. The nanowires with the average diameter about 2 nm and the length of several hundred nanometers were characterized by TEM, EDS, XRD. It is believed that FePt nanowires were generated via the catalytic solution-liquid-solid (S-L-S) synthetic approach. This process is strongly dependent on the solvent and barely on the reaction temperature and the concentrations of precursors.

Paddlewheel SBU based Zn MOFs: Syntheses, Structural Diversity, and CO2 Adsorption Properties.

Four Zn metal⁻organic frameworks (MOFs), {[Zn2(2,6-ndc)2(2-Pn)]·DMF}n (1), {[Zn2(cca)2(2-Pn)]·DMF}n (2), {[Zn2(thdc)2(2-Pn)]·3DMF}n (3), and {[Zn2(1,4-ndc)2(2-Pn)]·1.5DMF}n (4), were synthesized from zinc nitrate and N,N'-bis(pyridin-2-yl)benzene-1,4-diamine (2-Pn) with naphthalene-2,6-dicarboxylic acid (2,6-H2ndc), 4-carboxycinnamic acid (H2cca), 2,5-thiophenedicarboxylic acid (H2thdc), and naphthalene-1,4-dicarboxylic acid (1,4-H2ndc), respectively. MOFs 1⁻4 were all constructed from similar dinuclear paddlewheel {Zn2(COO)4} clusters and resulted in the formation of three kinds of uninodal 6-connected non-interpenetrated frameworks. MOFs 1 and 2 suit a topologic 48·67-net with 17.6% and 16.8% extra-framework voids, respectively, 3 adopts a pillared-layer open framework of 48·66·8-topology with sufficient free voids of 39.9%, and 4 features a pcu-type pillared-layer framework of 412·6³-topology with sufficient free voids of 30.9%. CO2 sorption studies exhibited typical reversible type I isotherms with CO2 uptakes of 55.1, 84.6, and 64.3 cm³ g-1 at 195 K and P/P0 =1 for the activated materials 1', 2', and 4', respectively. The coverage-dependent isosteric heat of CO2 adsorption (Qst) gave commonly decreased Qst traces with increasing CO2 uptake for all the three materials and showed an adsorption enthalpy of 32.5 kJ mol-1 for 1', 38.3 kJ mol-1 for 2', and 23.5 kJ mol-1 for 4' at zero coverage.

Detection of digoxin in urine samples by surface-assisted laser desorption/ionization mass spectrometry with dispersive liquid-liquid microextraction.

A novel method for the detection of digoxin using dispersive liquid-liquid microextraction (DLLME) coupled to the surface-assisted laser desorption/ionization mass spectrometric detection (SALDI/MS) was developed. Acetone and chloroform were used as the disperser solvent and extraction solvents, respectively. After the extraction, digoxin was detected using SALDI/MS with colloidal palladium as the matrix. Under optimal extraction and detection conditions, the calibration curve, which ranged from 0.01 to 0.50 µM, was observed to be linear. The limit of detection (LOD) at a signal-to-noise ratio of 3 was 2 nM for digoxin. With a sample-to-extract volume ratio of 400, the enrichment factor for digoxin was calculated to be 252. This novel method was successfully applied for the determination of digoxin in human urine samples.

Synthesis, structure, and transformation of novel osmium azine and ylide complexes.

Three novel triosmium complexes with unusual coordination characteristics are reported. Treatment of the hydridotriosmium cluster (mu-H)2Os3(CO)10 with CNNPPh3 in CH2Cl2 gave complexes (mu-H)Os3(CO)(10)(mu2-eta2-C(H)NNPPh3) (1) and (mu-H)Os3(CO)10(mu2-eta1-CHPPh3) (2). Complex 1 represents the first example of the existence of a coordinated phosphinazine ligand. An in-situ 1H NMR study showed that the reaction of (mu-H)2Os3(CO)10 with CNNPPh3 produced complex 1 as the initial product in 100% conversion. The latter is not stable in solution and slowly eliminates nitrogen to form an unusual ylide complex 2 in quantitative yield. The thermolysis of 2 in refluxing toluene afforded (mu-H)3Os3(CO)9(mu3-eta1-CCO2CH2Ph) (3) as a colorless compound. Complexes 1-3 were characterized by spectroscopic methods and single-crystal X-ray diffraction analysis. The interesting feature of structure 3 is the presence of a mu3-alkylidyne ligand where the symmetrically triply bridged CCO2CH2Ph fragment lies perpendicular to and above the triosmium triangle.