Periodic Reporting for period 2 - CCIMC (Coordination chemistry inspires molecular catalysis)
Reporting period: 2022-03-01 to 2024-02-29
Catalysis is a key technology for Europe. The production of 80% of industrially relevant chemicals involves catalysis, which accounts for about 20-30% of the World Gross Domestic Product. Therefore, catalysis lies at the heart of our chemical industry. Molecular catalysis is more efficient and selective than heterogeneous catalysis, while more robust and simpler to implement than the enzymatic approach used in biotechnologies. Major challenges for the future of mankind, where catalysis plays a determining role, are the development of “greener”, environmentally benign processes, the transition from fossil to renewable feedstocks for both energy and consumer products. Related issues are the mechanistic understanding of the catalytic processes, which is essential for optimization (greater productivity, lower energy consumption, lower waste production), and catalyst recovery (lower product contamination, preservation of low earth-abundant metal resources). Europe is a leading player in both academic catalysis research as well as in its industrial implementation, but this leadership is increasingly challenged by emerging as well as mature but still innovating economies. The aim of this ITN was to palliate research fragmentation by coordinating an innovative research programme at the European scale, on the basis of double doctoral degrees with the direct involvement of industrial partners, to train the next generation of researchers in molecular catalysis. Fifteen Early Stage Researchers (ESRs) have participated in the programme, each one working on a doctoral thesis jointly between two beneficiary research institutions in two different countries and with a secondment research period in one of the non-academic partner institutions. In addition to the project management (WP1), the action comprised four interlinked scientific work packages (WP2-5), a training work package (WP6), an outreach and public engagement work package (WP7) and an ethics work package (WP8).
The main results obtained by each ESR are as follows. ESR1 has synthesized several new NHC ligand precursors and obtained ruthenium olefin metathesis catalysis, aiming at selectivity in favour of the Z isomer. A benzimidazolidene-based Z-selective olefin metathesis catalyst developed by intelligent ligand design has shown higher activity and greater stability. This catalyst was applied to the synthesis of bio-based polymers from technical grade sunflower methyl oleate during the industrial secondment. ESR2 developed efficient catalytic systems for the synthesis of drugs and/or biologically active molecules via the asymmetric Rh-catalysed hydroaminomethylation of various alkenes, focusing on the first direct synthesis of Tolterodine. He also immobilized his catalyst on several solid supports for use in a continuous flow protocol. ESR3 has elucidated the mechanism of the alkali metal-catalysed P-H addition to alkynes (hydrophosphanylation and hydrophosphorylation) through experimental work and DFT calculations, elucidating the influence the alkali metal ions on the activity and revealed an unexpected light-induced dimerization process. ESR4 focused on carbon-based supports for the heterogenization of chiral catalysts. A catalyst grafted on graphene oxide has shown better performance for the Henry reaction. ESR5 tacked the challenging task of catalytically functionalizing fluorinated hydrocarbons. She could elucidate the mechanism of a metal-free hydrodefluorination of fluoropyridines and developed an unprecedented stoichiometry C-C bond formation from a C-F substrate. ESR6 evidenced a C-C coupling of carbon dioxide with an amidinate ligand in an alkaline-earth salt and developed a catalysed reduction by boranes to bis(boryl)acetals. ESR7 synthesized switchable ligands upon irradiation at specific frequencies and applied a Pd complex to a C-C cross-coupling reaction. ESR8 elucidated the effect of the alkali metal in the activating strong base on the activity of an iridium catalyst in asymmetric hydrogenation. ESR9 has developed core-crosslinked micelles as supports for metallic nanoparticles and implemented them under aqueous biphasic conditions. ESR10 developed functionalized Janus dendrimers, decorated with solubilizing groups and Ru-based complexes, with a clearly better performance in allyl alcohol isomerization relative to the model catalyst monomer.ESR11 has synthesised new functionalized ionic liquids and investigated their performance in the hydrogenation of unsaturated substrates by ruthenium, nickel, and core-shell ruthenium-rhenium metallic nanoparticles, obtaining better selectivities and activity under milder reaction conditions relative to the state of the art. ESR 12 has prepared and characterized a number of carboranyl bisphosphine ligands. ESR13 has obtained dendrimers for catalytic application in supercritical carbon dioxide and demonstrated greater activity for a precise asymmetrically disubstituted dendrimer relative to a stochastically substituted analogue. ESR14 has investigated the hydrogermylation and hydrosilylation reactions, unveiling a few unexpected transformations and developed a very efficient catalytic protocol for the hydrosilylation of nitriles. Finally, ESR15 has optimised the one-electron reduction and spin localisation onto the carbon atom of carbon dioxide though the use of a frustrated Lewis acid/base pair systems made of bulky N-heterocyclic carbenes and boranes. The CCIMC results have been disseminated by open access publications (24 at the time of submission of this report) and by presentations by the ESRs at various meetings (30 oral presentations, 58 poster presentations and 21 flash oral presentation + poster). The ITN activities have been regularly communicated to different target groups through the CCIMC website, through periodical Newsletters (ca. 4 per year), and through Twitter, LinkedIn and Instagram accounts.
The activity in WP2 has led to the fabrication of almost 20 new ligands. Work in WP3 has resulted in the development of over 30 new molecular precatalysts and several new supported pre-catalysts. The activity in WP4 has produced five in-depth mechanistic study, has revealed one new transformation involving the formation of a C-C bond by activation of a substrate C-F bond and two new processes involving the activation of carbon dioxide. Finally, numerous catalysed transformations have been investigated with the newly developed ligands and pre-catalysts, including several optimized processes in new confined media. In particular, eleven catalysed transformations were improved with respect to the state-of-the-art, either in terms of higher catalyst stability (turnover number), activity (turnover frequency), selectivity (lower content of undesired by-products) or simpler work-up procedures through confinement. The project also generated 5 new (previously unreported) catalysed transformations and four new photo-switchable catalytic processes. The exploitation of a few of these discoveries is under consideration by the industrial partners of this project, where the ESRs’ secondment took place.