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An experimental study of the plasma gas phase in low pressure radiofrequency discharges of oxygen is presented. The plasma phase has been studied by means of mass spectroscopy of the neutral and of the charged species, directly sampling the plasma gas phase. We also measured the ion energy distributions. We have studied the influence of the operating conditions on the plasma gas-phase composition. Ion density and energy have been measured as a function of discharge parameters. In particular, we have identified operating conditions in low pressure discharges allowing the extraction of ions from the plasma state with energies exceeding 50 eV. This makes plasma processing with energetic oxygen ions feasible in our device.

This work reports a statistical study on the relationship between the chemical-physical properties of CNTs, which vary by changing the conditions of purification and plasma treatment, and the macroscopic properties of PC-based nanocomposites. CNTs are synthesized and then purified in two different ways and used as fillers for the preparation of PC/CNTs nanocomposites. In some cases, oxygen plasma treatment is carried out to improve their affinity to the matrix. The CNTs are characterized by TGA, ICP/OES and FT-Raman spectroscopy, titration and morphological analysis. Mechanical, dynamic-mechanical, electrical and morphological tests are used for characterizing PC/CNTs nanocomposites.

The anionic cluster [Pt(19)(CO)(22)](4-) (1), of pentagonal symmetry, reacts with CO and AuPPh(3)(+) fragments. Upon increasing the Au:Pt(19) molar ratio, different species are sequentially formed, but only the last two members of the series could be characterized by X-ray diffraction, namely, [Pt(19)(CO)(24)(μ(4)-AuPPh(3))(3)](-) (2) and [Pt(19)(CO)(24){μ(4)-Au(2)(PPh(3))(2)}(2)] (3). The metallic framework of the starting cluster is completely modified after the addition of CO and AuL(+), and both products display the same platinum core of trigonal symmetry, with closely packed metal atoms. The three AuL(+) units cap three different square faces in 2, whereas four AuL(+) fragments are grouped in two independent bimetallic units in the neutral cluster 3. Electrochemical and spectroelectrochemical studies on 2 showed that its redox ability is comparable with that of the homometallic 1.

The dispersibility of unfunctionalized multi-walled carbon nanotubes in a polymer matrix is studied focusing on the role of the morphology and structure of the primary aggregates. The particles, synthesized by fluidized bed catalytic chemical vapor deposition and purified through a scalable one-pot method, are dispersed in polystyrene by melt mixing. The filler percolation threshold, assessed through rheological analyses and dielectric spectroscopy, is one order of magnitude lower than that of commercially available nanotubes with similar features. This is ascribed to the hierarchical structure of the primary aggregates, which facilitates both the infiltration of the polymer in the earlier stages of mixing and the pulling out of the nanotubes required for their individualization. The high dispersibility is not achieved to the detriment of the nanotube integrity, and the nanocomposites exhibit enhanced thermal stability and dynamic mechanical properties at low amounts of filler.

Pt-Sn heterometallic system shows a good catalytic activity in hydrogenation, isomerisation and hydroformylation of olefins, both in homogeneous and heterogeneous phase. Pt-Sn carbonyl clusters could have a similar behaviour. So, we have focused our attention on the reactivity of the dianion [Pt15(CO)30]2- with Sn-based reagents, in order to obtain new Pt-Sn species. The first reported Pt-SnCl2 cluster was [Pt8(SnCl2)4(CO)10]2- [1], while recently we have prepared and characterized the series [Pt5(CO)5{Cl2Sn(μ-OR)SnCl2}3]3− (R = H, Me, Et, iPr; 1−4) [2]. Here we report the preparation and characterization of different heteroleptic Pt-Sn clusters, containing, besides carbon monoxide, SnCl2, SnCl3 or PPh3 as ligands. Generally [Pt15(CO)30]2- and SnCl2 (and eventually PPh3) are the starting materials; by changing the experimental conditions (cluster counter-ion, reaction solvent, Pt:Sn molar ratio) it is possible to selectively obtain different products. The parent [Pt6(SnCl2)2(SnCl3)4(CO)6]4- cluster has been used to prepare a new series of carbonyl clusters as summarized in the following reaction scheme. The new compounds have been structurally characterized by single crystal x-ray diffraction analysis.