Reaction of Bare VO+ and FeO+ with Ammonia: A Theoretical Point of View

Infrared photodissociation spectroscopic investigation on VO+ and NbO+ hydrolysis catalyzed by water molecules

We investigate the hydrolysis of vanadium/niobium monoxide cation (VO⁺/NbO⁺) with water molecules in the gas phase.

Curly arrows, electron flow, and reaction mechanisms from the perspective of the bonding evolution theory

Despite the usefulness of curly arrows in chemistry, their relationship with real electron density flows is still imprecise, and even their direct connection to quantum chemistry is still controversial. The paradigmatic description - from first principles - of the mechanistic aspects of a given chemical process is based mainly on the relative energies and geometrical changes at the stationary points of the potential energy surface along the reaction pathway; however, it is not sufficient to describe chemical systems in terms of bonding aspects. Probing the electron density distribution during a chemical reaction can provide important insights, enabling us to understand and control chemical reactions. This aim has required an extension of the relationships between the concepts of traditional chemistry and those of quantum mechanics. Bonding evolution theory (BET), which combines the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT), provides a powerful method that offers insight into the molecular mechanism of chemical rearrangements. In agreement with the laws of physical and aspects of quantum theory, BET can be considered an appropriate tool to tackle chemical reactivity with a wide range of possible applications. In this work, BET is applied to address a long-standing problem: the ability to monitor the flow of electron density. BET analysis shows a connection between quantum mechanics and bond making/forming processes. Likewise, the present approach retrieves the classical curly arrows used to describe the rearrangements of chemical bonds and provides detailed physical grounds for this type of representation. We demonstrate this procedure using the test set of prototypical examples of thermal ring apertures, and the degenerated Cope rearrangement of semibullvalene.

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation

The displacement of the nuclei along the reaction path provides an explanatory interpretation of the electron density transfers making possible to understand chemical reactions.

Topological analysis of the reaction of uranium ions (U+, U2+) with N2O in the gas phase

Density functional theory calculations were performed to study the ability of uranium cations, U(+) and U(2+), to activate the N-N and N-O bonds of N(2)O. A close description of the reaction pathways leading to different reaction products is presented. The obtained results are compared with previous experimental works. The nature of the bonding of all the involved species and the bonding evolution along the reaction pathways was studied by means of the topological analysis of the ELF function.

On the Origin of the Different Performance of Iron and Manganese Monocations in Catalyzing the Nitrous Oxide Reduction by Carbon Oxide

The potential energy profiles for the Fe+- and Mn+-assisted reduction of N2O by CO were studied at the B3LYP density functional level in order to get the differences in the reaction mechanisms determining the efficiency of iron and the inactivity of manganese as ionic catalysts. Both ground and excited states of cations were taken into account in view of a possible participation of the highest multiplicities to the reduction process. Results indicated that a spin inversion occurs in the rate-determining step of iron ion-catalyzed reaction that improves the performance of the cation. However, also in the absence of the two-state reactivity phenomenon, contrary to manganese ion, iron is active in catalyzing the reaction.

Density Functional Study of Ammonia Activation by Late First-Row Transition Metal Cations

Density functional theory (DFT) in its B3LYP implementation is used to investigate the reaction of ammonia with the late (Co(+), Ni(+), and Cu(+)) first-row transition metal cations in both high- and low-spin states. The potential energy surfaces (PES's) leading to three different exit channels are closely examined. The binding energies for the reaction products are calculated and compared with the corresponding experimental values. A comparison with our earlier works covering the reactivity of the Sc-Fe series of cations is made in order to underline similarities and differences of the reaction mechanisms as well as to establish trends along the row.