Abstract
In this thesis, molecular dynamics simulations and quantum chemical calculations are employed to investigate guest-encapsulations and rate-enhancements in a K12[Ga4L6] supramolecular metallocage developed by the Raymond group. Encapsulation of cationic guest molecules has been investigated to establish a protocol validated against numerical experimental data. Their binding Gibbs energies were computed with MD simulations using the attach-pull-release (APR) approach. Based on the excellent agreement between calculations and experiments (the absolute deviation of up to ca. 2.0 kcal/mol), a parametrization procedure is proposed to better quantify the non-standard parameters of the system. The Gibbs energy barrier for encapsulation is also determined by the potential of mean force constructed from the umbrella sampling (US) simulations with the weighted histogram analysis method (WHAM). A description at a molecular level of the encapsulation is obtained. The origin of enzymelike rate enhancements in C-C bond formations from Au(III) and Pt(IV) complexes and in the Nazarov reaction have been investigated by QM calculations guided by MD simulations. For the former, the analysis of the rate acceleration performed in terms of microsolvation and encapsulation shows that microsolvation term is different for these two metal complexes (much larger for Au(III) complex than for Pt(IV) complex) and the interaction between the metal complex and metallocage is the main contribution to the catalysis upon the encapsulation. For the Nazarov reaction, the pre-organization of the substrate and the stabilization of the protonated substrate are fundamental to this rate enhancement. The encapsulation of the substrate by the metallocage induces the substrate pre-organization. The protonation of the substrate is substantially stabilized by the metallocage, indicating a shift of the basicity of the alcohol substrate in the metallocage which is the main factor in this catalysis. Overall, the results presented in this thesis show the usefulness of computational methods to deepen understanding encapsulation and catalytic processes in supramolecular metallocagesPalabras clave
| Date of Award | 1 Dec 2021 |
|---|---|
| Original language | English |
| Supervisor | Jeandi Marechal (Director) & Gregori Ujaque Perez (Director) |