Overall, the project has been highly successful. We have been able to demonstrate, for the first time, that it is possible to design a FLP system entirely based on transition metals (which we have coined with the term “TMOFLP”). We achieved this important goal by combination of two sufficiently bulky transition-metal based fragments of acidic and basic Lewis character (Figure 1). The bulkiness of the phosphine ligands quench Lewis adduct formation and confer high potential for small molecule activation. These results were published in JACS as a single-author paper (2017, 139, 2944).
Figure1. Activation of H2 and C2H2 by a TMOFLP based on Au(I) and Pt(0) complexes stabilized by bulky phosphine ligands. ORTEP diagrams for compounds 3a, 4a and 5a are represented.
One of the advantages of incorporating transition metals into FLP designs derives from the easiness of steric and electronic tuning by ligand modification, in stark contrast with the often difficult synthetic protocols to access acidic boranes typically used in traditional FLPs. We have demonstrated that by slight tuning of the steric properties of terphenyl phosphine ligands it is easy to alter the regioselectivity of the aforementioned transformations (Figure 2). In addition, we have elucidated the reaction mechanisms by a joint experimental/computational effort, results that will be shortly published.
Figure 2. Selectivity in the activation of acetylene by our TMOFLP system.
Overview of the dissemination of results
Publications
1. Campos, J.*. Dihydrogen and Acetylene Activation by a Gold(I)/Platinum(0) Transition Metal Only Frustrated Lewis Pair, J. Am. Chem. Soc. 2017 (single-author paper), 139, 2944.
(Repository:
https://idus.us.es/xmlui/handle/11441/55206(öffnet in neuem Fenster))
2. Campos, J.* Pares de Lewis frustrados basados en metales de transición. An. Quím. 2017, 113, 224-230. (Open Access)
3. Hidalgo, N.; Pérez-Jiménez, M.; Moreno, J. J.; López-Serrano, J.; Carmona, E.*; Campos, J.* Tuning the Selectivity of Alkyne Activation by a Transition Metal Only Frustrated Lewis Pair. Manuscript in preparation.
Dr. Campos has submitted two other papers that are now under review and are related to the present project by the central idea of developing novel cooperative catalysts.
4. Moreno, J. J.; Espada, M. F.; Krüger, E.; López-Serrano, J.; Campos, J.*; Carmona, E. Ligand Rearrangement and Hemilability in Rhodium(I) and Iridium(I) Complexes Bearing Terphenyl Phosphines, 2018, submitted to EurJIC.
5. Campos, J.* Dehydrogenation of alcohols and polyols from a hydrogen production perspective. 2018, submitted to Physical Sciences Reviews (Open Access).
Other dissemination activities
Invited seminars: 4 invited seminars at the Universities of Granada and Vigo and by the Royal Academy of Sciences of Sevilla.
Conferences: 2 Plenary talks at the XIV Young Researchers Symposium (Badajoz) and the 1st Conference of PhD students (Sevilla)
Outreach activities: 4 invited talks in different events such as the European Researchers´ Night.
Other relevant achievements
Dr. Campos carried out a secondment period at the University of Oxford within the group of Prof. Simon Aldridge. During that stay Dr. Campos was able to elucidate the nature of a silicon species that was very recently reported to be a cAAC-silicon(I) radical (Angew. Chem. Int. Ed. 2017, 56, 7573). Instead of being a radical the reported purple compound could be a silicon(II) dimer with a Si-H termini that would better fit with all experimental observations. We are currently preparing a manuscript to report these results.
The most important outcome from this Marie Curie project it perhaps the fact that it served as the experimental seed that justify a later ERC Starting Grant proposal prepared by Dr. Campos and recently funded (CoopCat). This proposal focuses on developing innovative cooperative strategies for catalysis. The results derived from this Marie Curie IF, mainly the demonstration that a TMOFLP can be prepared, was certainly very important to get the ERC project funded. This latter achievement is in fact the reason to request an early termination for the Marie Curie proposal, but the science behind it will continuously develop over the following years under the umbrella of Dr. Campos’ ERC StG.
