A technique has been developed that provides a solution to the very considerable technical problem of preparing gas-phase complexes from transition metals in their higher oxidation states, i.e., Cu(II), Cr(III), Fe(II), etc. Charge transfer prevents complexes, such as [Cu•(H 2 O) n ] 2+ , from being prepared via nucleation about an ion core, and yet these ions are pivotal to an understanding of transition metal chemistry. Discussed here are new results from a technique that appears capable of producing complexes from a wide variety of metals and ligands. Data are presented for copper(II) in association with 20 different ligands, including water, ammonia, pyridine, tetrahydrofuran, and benzene. For each [Cu•L n ] 2+ system, two important quantities are identified: (i) the minimum number of ligands required to form a stable unit and (ii) the value of n for which the intensity distribution reaches a maximum. The data show considerable variation as a function of the composition and size of solvent molecule, with evidence of stable coordination shells containing between 2 and 8 molecules. In most instances, coordination shells containing more than four molecules can be attributed to the formation of an extended network of hydrogen bonds. Collisional activation of size-selected clusters reveals the presence of extensive ligand-to-metal electron transfer in the smaller complexes, and in several cases, charge transfer is also accompanied by chemical reactivity. The extent of charge transfer is frequently observed to be determined by the stability of the singly charged metal-containing product.

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The shock-wave resistance of WS(2) nanotubes has been studied and compared to that of carbon nanotubes. Detailed structural features of post-shock samples were investigated using HRTEM, XRD, and Raman spectroscopy. WS(2) nanotubes are capable of withstanding shear stress caused by shock waves of up to 21 GPa, although some nanotube tips and nanoparticles containing multiple structural defects in the bending regions are destroyed. Small WS(2) species, consisting of only a few layers, are extruded from the nanotubes. Well-crystallized tube bodies were found to exhibit significant stability under shock, indicating high tensile strength. XRD and Raman analyses have confirmed this structural stability. Under similar shock conditions, WS(2) tubes are more stable than carbon nanotubes, the latter being transformed into a diamond phase. WS(2) nanotubes containing small concentrations of defects possess significantly higher mechanical strength, and, as a consequence, hollow WS(2) nanoparticles are expected to act as excellent lubricants under much higher loading than was previously thought.

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Nitrogen-modified TiO 2 thin films are obtained, for the first time, from aerosol-assisted (AA)CVD-prepared samples via a posttreatment method involving immersion in liquid ammonia to achieve nitrogen-modified TiO 2 and visible-light photo-activity. The resulting modified and unmodified TiO 2 films are characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution (HR)TEM, energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SAED), UV-vis spectroscopy, and X-ray photoelectron spectroscopy (XPS). This shows that the films are $200 nm thick and contain anisotropic crystals of anatase TiO 2 . XPS shows that the nitrogen is successfully added to the surface of the film interstitially at 0.7 at.-%, but is only present to a film depth of 50 nm. The nitrogen doping causes a red shift in the absorption band and a band gap narrowing of $0.1 eV. The surface-bound nitrogen results from the post-treatment method of doping where the films are soaked in liquid ammonia before annealing. The photocatalytic efficiencies of the films under visible light (>385 nm) are evaluated by measuring formaldehyde formation from the probe molecule tris(hydroxymethyl)aminomethane (Tris). Hydrogen abstraction from Tris, obtained from, e.g., photocatalytically produced OH radicals, leads to formaldehyde formation which is then detected through a modified version of the Hantzsch reaction. The results show that the N-modified film possess remarkable photocatalytic properties with an apparent photochemical quantum yield of $8%.

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