Ricerc@Sapienza

We study the effects of cation inversion x (Mg ↔ Al, with x representing the fraction of Mg and Al exchanged) and magnetic substitution (Mn → Mg) on the elastic properties of the MgAl2O4 spinel system using density functional theory and Brillouin scattering techniques. Our computations show that cation inversion decreases the molar volume of spinel and produces a stiffening of C11 and a softening of C12. Simulations and experiments agree within 2%. Density functional theory also captures the qualitative effect of Mg ↔ Al on C44, that is, an initial softening for inversion degree at x

The contamination with water of the cathodic ACN-Et4NBF4 solution gave us the opportunity to investigate alkyl isocyanate reactivity toward electrogenerated anions. The cathodic reduction of a ACN-Et4NBF4 solution led to the formation of both hydroxide and cyanomethyl anions. The reaction of the catholyte with cyclohexylisocyanate led to the exclusive formation of acetamidated product, with no traces of cyanomethylated one. On the contrary, when reacting with benzaldehyde only the cyanomethylated was isolated.

All possible monohydroxycoumarin derivatives are modeled using density functional theory computations in order to investigate the role of the hydroxyl group position for the radical-scavenging and antioxidant activity of these compounds. Geometry optimization is performed using the B3LYP functional with the 6-311++G(d,p) basis set. The enthalpy changes are assessed in gas phase and in implicit water using the polarized continuum model. Structure-reactivity patterns are delineated.