Dottorato di Ricerca in Metodologie Chimiche Inorganiche,XXIII Ciclo,a.a. 2009-2010Density functional theory calculations were performed to study the ability of
thorium (Th+, Th2+) and uranium (U+, U2+
The potential energy surfaces were explored taking into consideration different
spin states. A close description of the reaction pathways leading to different reaction
products is presented, and the obtained results are compared with experimental data.
) cations to activate the C-H and C-C bonds
of methane, ethane and propane in the gas-phase.
Th+ activates the C-H bonds of methane and ethane, in contrast, U+ is inert in both
reactions. Th2+ reacts with all three alkanes, whereas U2+ reacts with C2H6 and C3H8,
with product distributions different than those of Th2+
The computed potential energy profiles, which all proceed by insertion, were used
to evaluate the relationship between the energetics of the bare Th
.
+ (2+) and U+ (2+) ions
and the energies for C-H and C-C bond activation. It was found that the computed
energetics for insertion are entirely consistent with the empirical model which relates
insertion efficiency to the energy needed to promote the An+ (2+) ion from its ground
state to a prepared divalent state with two non 5f valence electrons suitable for bond
formation in {C-An+ (2+)-H} and {C-An+ (2+)-C} activated intermediates.Università della Calabri