No abstract

While the activity of the SMAD powders is lower than that of pure silver nitrate, it has the ability to kill bacteria very effectively and over long periods of time.

A new tiara Pd(II) thiolate complex, [Pd(SC12H25)2]6, has been synthesized and fully characterized by X-ray single crystal analysis, elemental analysis, MALDI, 1H NMR, powder XRD, IR, Raman, and UV/vis. It was found that, in each complex cluster, the six palladium atoms form a nearly planar hexagonal ring and the adjacent palladium atoms are bridged by sulfur atoms from both sides. Then the complex was further used as a single-source precursor to prepare nearly monodisperse palladium sulfide (PdS) nanoparticles through the high-temperature-induced decomposition in diphenyl ether. The obtained nanoparticles are 2.87 +/- 0.51 nm in diameter and protected by a layer of thiolate species on the surface.

We describe a remarkable and simple alloying procedure in which noble metal intermetallic nanoparticles are produced in gram quantities via digestive ripening. This process involves mixing of separately prepared colloids of pure Au and pure Ag or Cu particles and then heating in the presence of an alkanethiol under reflux. The result after 1 h is alloy nanoparticles. Particles synthesized according to this procedure were characterized by UV-vis spectroscopy, EDX analysis, and high-resolution electron microscopy, the results of which confirm the formation of alloy particles. The particles of 5.6+/-0.5 nm diameter for Au/Ag and 4.8+/-1.0 nm diameter for Cu/Au undergo facile self-assembly to form 3-D superlattice ordering. It appears that during this digestive ripening process, the organic ligands display an extraordinary chemistry in which atom transfer between atomically pure copper, silver, and gold metal nanoparticles yields monodisperse alloy nanoparticles.

Gold and platinum nanoparticles were prepared using a reverse micelle technique, creating products with several particle sizes. The stabilized metal nanoparticles can be deposited over long-range distances forming ordered arrays using supercritical carbon dioxide to remove the colloid solvent. The use of supercritical carbon dioxide creates uniformly deposited particle layers and can be removed without disturbing the precipitated particles. We also show that these nanoparticles can be deposited efficiently in nanometer trenches, which is not possible using conventional particle deposition by liquid evaporation.