Machine Learning Catalysis

Machine learning is becoming a powerful tool in computational chemistry. Its use in catalysis is challenged by several factors including the lack of big experimental data for training predictive models. This problem can be tackled by using computational data for training, following an approach known as quanutm-based machine learning. We started this new research line in 2019 with a collaboration with the Aspuru-Guzik group, focusing on the prediction of oxidative addition barriers in the chemical space surrounding Vaska's complex. Future work in this direction will focus on the development of predictive and generative models. The goal is to maximize the accuracy, transferability, and explainability of these models in the field of transition metal catalysis.

C-H & Water Oxidation with Doped Cubanes 

[email protected] are cobalt-oxide cubanes in which one of the copper atoms is replaced by a dopant metal (e.g. manganese); dangling metals can also be appended. These complexes are experimental molecular models of the photosystem II and the metaloxide-based materials. In this project, we are collaborating with the Tilley group to determine the structure and reactivity of the doped cubanes in the activation of strong C-H bonds and the oxidation of water. The possibility of extending or doping the cubane with different late transition metals allows for fine tuning their chemical properties (redox potentials, activation barriers, etc.). Bastian is working on the exploration of the [email protected] chemical space by combining DFT and DLPNO-CCSD(T) calculations. Other projects include cubane-supported Ru(V)-oxo species and all-cobalt cubanes.

Carbon Dioxide Reduction with Molecular Catalysts and Nanoporous Materials

Our computational work on the catalytic reduction of CO2 is following two different lines: 1) Lluís is performing static-DFT and microkinetic studies on bifunctional catalysts based on iron and molybdenum; 2) Torstein and Robert are performing periodic-DFT studies on nanoporous catalytic materials based on the UiO zirconium MOFs. At the intersection between these two lines, we are exploring the possibility of supporting metal catalysts at the linker and/or SBU of the MOFs. These projects have a strong multidisciplinary character, involving multiple collaborations with the groups of HopmannHazari, BernskoetterOlsbye and Beller. These research lines are strongly supported by the nordCO2 consortium led by Kathrin Hopmann at the UiT (Norway). The postdoctoral position of Torstein is supported by this consortium, with Ainara acting as the PI in Oslo.

CuAAC Reaction

The CuAAC reaction is the copper-catalyzed cycloaddition of an azide to an alkyne. This reaction is catalyzed by simple copper salts and the nature of the active species (nuclearity) in the mechanism has been debated for a long time. In this project, we are collaborating with the Tilley group to determine the mechanism operating with a robust dicopper catalyst supported by a pentadentate P,N4 ligand. The strong chelating effect of this ligand sets and keeps the dinuclear nature of the system, facilitating the isolation and characterization of reaction intermediates. Julie is carrying out DFT calculations and microkinetic modeling to determine the key steps involved in the activation of the catalyst and the catalytic cycle.

Gold(III) Chemistry and Catalysis

Gold(III) species have been postulated as transient intermediates in metal-catalyzed processes. This project is carried out in collaboration with the experimental group of Tilset and has the goal of synthesizing gold(III) complexes that are enough stable as to be isolated and characterized, yet enough reactive as to catalyze the functionalization of double- and triple-CC bonds with nucleophiles. Since the start in 2012 at the CTCC (the precursor of the Hylleraas Center), the project has made several contributions to the field, including the first gold(III)-olefin complex, the mechanism of ethylene insertion into gold(III)-oxygen bonds and the catalytic functionalization of acetylene.

In- and Off-Cycle Chemistry in Metal-Catalyzed Cross-Coupling Reactions 

In this project we focus on the off-cycle chemistry of metal-catalyzed cross-coupling reactions. In collaboration with the Hazari group, we have combined calculations and experiments to understand the off-cycle reactions associated with catalytic systems based on palladium and nickel. In the case of palladium, we explored the formation of dinuclear complexes and how electronic and steric effects can be combined to reduce its detrimental effects on catalysis. In the case of nickel, the mechanistic studies focused on the formation of Ni(I) species by comproportionation between the Ni(II) pre-catalyst and the Ni(0) active species. This work was recently reviewed by Ainara and David in a Perspective for the ACS Catalysis journal.