Easy Access to Phosphido-Selenido Clusters. Reaction of [Ru3(CO)12] with Ph2(pyth)PSe {pyth=5-(2-Pyridyl)-2-Thienyl} and Crystal Structure of [Ru3(μ3-Se)(μ-PPh2)(μ-pyth)(CO)6{P(pyth)Ph2}]

The reaction of [Ru₃(CO)₁₂] with Ph₂(pyth)PSe (pyth=5-(2-pyridyl)-2-thienyl) allows to obtain two novel clusters [Ru₃(₃-Se)₂(CO)₇{P(pyth)Ph₂}₂] 1 and [Ru₃(₃-Se)(-PPh₂)(-pyth)(CO)₆{P(pyth)Ph₂}] 2 in satisfactory yields. The first one exhibits the well-known bicapped, open triangular, 50-electron nido-core, whereas 2, whose crystal structure has been determined, shows the rather rare Ru₃Se tetrahedron with the Ph₂P and pyth fragments as side-bridging ligands. Morever cluster 2 belongs to the exiguous family of selenido-phosphido clusters not easily achievable by other routes.     

Synthesis of octahedral zirconium complex bearing [NHC?O] ligands,and its behavior as catalyst in the polymerization of olefins

The synthesis and characterization of a zirconium complex, having two alkoxide functionalized N‐heterocyclic carbene ligands, and its behavior as catalyst in the polymerization of ethylene and propylene, have been reported. NMR analysis showed that more than one species was obtained during synthesis. These data were confirmed by ethylene polymerization that gave rise to a linear polyethylene having a high Molecular weight and a polydispersity index (MDI) > 2 and often bimodal. The same catalytic system was able to produce highly isotactic polypropylene together with an atactic fraction. DFT studies on the complex stereoisomer stability gave indications on the species possibly involved in the polymerizations. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Quantification methods of amorphous/crystalline fractions in high-energy ball milled pharmaceutical products

In this work, thermoanalytical, diffractometry, and microscopy measurements have been performed in order to characterize the effect of high energy milling on a drug active in the migraine prophylaxis and smoke cessation. We can assert that the mechanical treatment induces only a partial amorphisation of the solid phase, in particular it reduces the crystal order by producing lattice defects which propagate from the surface to the bulk crystal. For this reason, the DSC is able to detect the presence of ordered solid, while the powder X-ray diffractometry, because of its low penetration depth, does not reach the crystalline core of the particles.     

Entanglement as a Semantic Resource

The characteristic holistic features of the quantum theoretic formalism and the intriguing notion of entanglement can be applied to a field that is far from microphysics: logical semantics. Quantum computational logics are new forms of quantum logic that have been suggested by the theory of quantum logical gates in quantum computation. In the standard semantics of these logics, sentences denote quantum information quantities: systems of qubits (quregisters) or, more generally, mixtures of quregisters (qumixes), while logical connectives are interpreted as special quantum logical gates (which have a characteristic reversible and dynamic behavior). In this framework, states of knowledge may be entangled, in such a way that our information about the whole determines our information about the parts; and the procedure cannot be, generally, inverted. In spite of its appealing properties, the standard version of the quantum computational semantics is strongly “Hilbert-space dependent”. This certainly represents a shortcoming for all applications, where real and complex numbers do not generally play any significant role (as happens, for instance, in the case of natural and of artistic languages). We propose an abstract version of quantum computational semantics, where abstract qumixes, quregisters and registers are identified with some special objects (not necessarily living in a Hilbert space), while gates are reversible functions that transform qumixes into qumixes. In this framework, one can give an abstract definition of the notions of superposition and of entangled pieces of information, quite independently of any numerical values. We investigate three different forms of abstract holistic quantum computational logic.     

Anomalies and proximity effect in high-T C tunnel junctions

Summary Some of the main anomalies in conductance characteristics of high-T _C tunnel junctions are considered. Mainly, the extreme, depression of gap structures, the presence of conductance peaks in corrispondence to the counterelectrode gap, and ?zero-bias anomalies? will be examined. The possibility of application of the proximity McMillan model to describe the behaviour in conductance of high-T _C junctions is considered. Discussion and preliminary comparison with experimental data on YBCO junctions are also reported.