Understanding the reactivity of frustrated Lewis pairs

Laburpena

The primary aim of this doctoral thesis is the rationalization of the reactivity of the so-called Frustrated Lewis Pairs (F LPs) using state-of-the-art quantummechanical calculations. To this end, we have applied a methodology based on the combination of the so-called Activation Strain Model (ASM) of reactivity and the Energy Decomposition Analysis (EDA) methods. This approach is nowadays considered as a powerful tool to not only quantitatively understand those factors controlling the reactivity of different chemical systems but also to design new and more efficient transformations. Specifically, we explored the influence of the nature of the Group 13/Group 15 pairs in geminal F LPs on the dihydrogen activation reaction. Our results identified the geminal N/ Al-based F LP as the most active system for the activation of 1-12. In addition, the influence of the nature of the Group 14 atoms (Si, Ge, Sn) on the reactivity of geminal F LPs has been also considered. Moreover, our calculations suggest that geminal F LPs featuring an antiaromatic borole fragment as the acid partner exhibit a remarkable reactivity enhancement compared to more traditional FLPs. Regarding intermolecular systems, we studied the role of carbones and its heavier analogues (ylidones) as basic functionalities in F LP chemistry and found that these species are comparatively more reactive than more traditional intermolecular F LPs composed of phosphines. Furthermore, the role of F LPs as ambiphilic ligands in gold(l)-catalyzed reactions has been also investigated explored. We found that P/B-based F LP ligands in gold(l)-complexes establish a relatively strong Au-B interaction which significantly enhances the catalytic activity of the corresponding gold(l)-complexes. Finally, we computationally studied the so far poorly understood cooperative action of the F LP antagonists in the activation of a single C¿F bond activation in polyfluoride substrates. Our calculations revealed the occurrence of crucial non-covalent interactions established between the Lewis base and the substrate which leads to the formation of an unusual hypervalent intermediate featuring a pentacoordinate carbon atom. We do believe that the insight derived from the present doctoral thesis has contributed significantly to our current understanding of the reactivity of F LPs. In our opinion, the results presented herein are expected to promote further theoretical and experimental studies in the growing and prosperous chemistry of these fascinating systems.