Computational Mechanistic Studies on the Transition Metal Catalyzed Activation of Carbon Dioxide

Identificador:  TDX:2714

Handle: https://hdl.handle.net/20.500.11797/TDX2714

Autors:  Kuniyil, Rositha

Resum:
The mechanism of representative examples of reactions involving carbon dioxide and transition metal complexes is characterized with the help of a variety of computational methods: DFT (Density Functional Theory), DFT/MM (DFT/molecular mechanics) and microkinetic models. Three different processes are analyzed. The palladium-catalyzed and aluminium-assisted carboxylation of allene species is found to take place through a complex mechanism that can explain all experimental data provided by stoichiometric reactions on specific steps by Hazari and co-workers. The tri(ethyl)aluminum additive is found to play a key role both in carbon dioxide and allene activation. The fluoride-assisted reaction of carbon dioxide with siloxy silanes is found to be significantly affected by the nature of the counterion accompanying the fluoride anion, which participates in the two silyl abstraction steps of the reaction. The mechanism of the palladium-catalyzed conversion of cyclic carbonates into allylic amines and allylic aldehides was examined in collaboration with the experimental group of Kleij, in our same Institute. We found out a mechanism with a key cyclometallated intermediate that explains the high selectivity of the process. We expect that these computational studies will contribute to the understanding of important details of the addressed reactions, and also to the design of more efficient strategies for attaining a more sustainable chemistry based on the activation of carbon dioxide.