Ricerc@Sapienza

The photoionization dynamics of OsO4 and RuO4, chosen as model systems of small-size mononuclear heavy-metal complexes, has been theoretically studied by the time-dependent density functional theory (TDDFT). Accurate experimental measurements of photoionization dynamics as a benchmarking test for the theory are reported for the photoelectron asymmetry parameters of outer valence ionizations of OsO4, measured in the 17-90 eV photon energy range. The theoretical results are in good agreement with the available experimental data.

The results of a potentiometric and calorimetric study on the complexation reactions of neutral N-donor ligands 1,4-diaminobutane (dab) and 1,5-diaminopentane (dap) with silver(I) in dimethylsulfoxide (DMSO) are reported. The investigation is extended for dab ligand to the aprotic solvent acetonitrile (AN), which presents quite different dielectric constant and donor number with respect to DMSO. In both solvents, polynuclear Ag2L 2+2 and Ag2L 2+3 species of high stability are formed, which inhibit the formation of mononuclear ones.

The hyperlithiated species Lik+1Fk (k=1, 2, 3, and 4) have been studied by quantum mechanical (QM) methods. Different structures have been localized for each molecule by the CBS-QB3 composite method: all the isomers show superalkali properties and strong tendency to donate an electron to carbon dioxide forming stable Lik+1Fk … CO2 complexes. With the aim to find molecular systems able to stabilize superalkalis, geometries of complexes between superalkalis and pyridine and superalkalis and graphene surfaces doped with a pyridinic vacancy were calculated.

In this work pharmaceutical application of focused library of six quinoline-based chalcogensemicarbazones (QBCs) was tested through determination of their antimicrobial activity against twenty-eight Gram-negative and Gram-positive strains from different origin. Pharmacokinetic properties have been assessed by the analysis of frequently employed drug likeness parameters. Computational study has been complemented with calculation of their global and local reactive properties, within the framework of density functional theory (DFT).

The reactivity between NO and the oxidized form of a short-distance dinuclear Cu-ZSM-5 catalyst (ZCu2O) was investigated. ZCu2O, which contains the [Cu–O–Cu]2+bridge coordinated at the opposite T11 positions of the M6 ring of ZSM-5, is obtained by the spin-forbidden decomposition of N2O on the reduced form of the catalyst, ZCu2, with an activation energy of about 18 kcal mol−1. The further addition of NO to the [Cu–O–Cu]2+unit of ZCu2O occurs in the doublet state without activation energy and gives NO2.

Riassunto – Il concetto di elettronegatività gioca un ruolo fondamentale in chimica. È di interesse conoscere l’elettronegatività dei gas nobili poiché, a causa della configurazione elettronica degli orbitali di valenza s2 (He) e s2 p6 (Ne, Ar, Kr, Xe, Rn), a prescindere dalla scala di elettronegatività utilizzata, l’intuito chimico suggerisce che essa dovrebbe essere molto inferiore rispetto all’elettronegatività di tutti gli altri atomi nella tavola periodica.

Background: Antioxidant properties have been recently suggested for caffeine that seems showing protective
effects against damages caused by oxidative stress. In particular, a HO% scavenging activity has been ascribed to
caffeine. Even if the oxidation of caffeine has been widely studied, the antioxidant mechanism is still far to be
understood.
Methods: The electrochemical behavior of caffeine, theobromine and theophylline was studied in aprotic
medium by cyclic voltammetry and electrolysis in UV–vis cell; a computational analysis of the molecular

Thin films of an iron(ii) complex with a photochromic diarylethene-based ligand and featuring a spin-crossover behaviour have been grown by sublimation in ultra-high vacuum on highly oriented pyrolytic graphite and spectroscopically characterized through high-resolution X-ray and ultraviolet photoemission, as well as via X-ray absorption. Temperature-dependent studies demonstrated that the thermally induced spin-crossover is preserved at a sub-monolayer (0.7 ML) coverage.