Electro- and Photocatalytic CO2 to CO Reduction Mechanism with Cobalt Complexes

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The burning of fossil fuels is causing a global climatic emergency. In order to solve this crisis, is very important to improve the efficiency of the production of renewable energies by transforming CO2 into carbon-based fuels. In this report, the member of the DIMOCAT Josep M. Luis in collaboration with the Julio Lloret group, determined the mechanism and bottlenecks of the CO2 reduction reaction with a model cobalt catalyst. The theoretical calculations, in combination with in situ measurements, pinpointed an elusive cobalt(I) carbonyl intermediate, which is formed very early in the reaction and is responsible for one of the most problematic bottlenecks in the CO2 reduction process. The mechanistic studies allowed the identification the bottlenecks of the reaction and the design of a photocatalytic strategy to break the carbonylic compounds  and then strongly improve the efficient of the catalytic reduction of the CO2.

Sergio Fernández, Federico Franco, Carla Casadevall, Vlad Martin-Diaconescu, Josep M. Luis, Julio Lloret-Fillol.

“A Unified Electro- and Photocatalytic CO2 to CO Reduction Mechanism with Aminopyridine Cobalt Complexes”

J. Am. Chem. Soc. 2019, ASAP

https://pubs.acs.org/doi/10.1021/jacs.9b06633

JACS

 

Visit of Kamila Pruszkowska

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Kamila Pruszkowska is a PhD student supervised by Prof. Michal Cyranski in the University of Warsaw . She has been working in our group for the last six weeks working in the study of the 1,2-bis(4-methylbenzoylvinylamino)ethane and Ni (II) 1,3-bis(4-methylbenzoylvinylamino)propane Ni(II) complexes coordinated to pyridine, 4-dimethylaminopyridine, 4-metoxypyridine, N-methyloimidazole, and thiazole ligands. She has been financed by an HPC-Europa3 fellowship and during her stay in our group she has been supervised by Dr. Olga A. Stasyuk and Dr. Miquel Solà. We are very happy to have had her in our group! We hope she has enjoyed her stay!

Kamila in the center with Olga and Miquel

Dandan Chen will be working in the DiMoCat group for the next 18 months

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Starting 4th September, we have a new visitor to our research group. Her name is Dandan Chen and she is a PhD student working in the group of Prof. Jun Zhu in the University of Xiamen (China). She will work with Dr. Miquel Solà on inorganic and organometallic species having aromaticity in their triplet states as a part of her PhD thesis. She will stay in Girona for about one year and a half. Welcome Dandan! Have a nice stay with us!

Dr. Anna Pla Quintana visiting researcher at UCDavis(California)

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Dr. Anna Pla Quintana is visiting Prof. Jared T. Shaw laboratories at UCDavis (California) (https://shaw.faculty.ucdavis.edu/) during a sabbatical term (September-December 2019) funded by a “Estancias de profesores e investigadores sénior en centros extranjeros” grant from the Ministerio de Ciencia, Innovación y Universidades. She will be involved in a project aimed to the synthesis of anticancer drugs using Rh-catalyzed carbene C-H insertion reactions. The mechanism of the transformation developed will also be studied theoretically in collaboration with Prof. Dean Tantillo (UCDavis) (http://blueline.ucdavis.edu/). We wish Anna a great time in UCDavis!

Anna in her office in UCDavis.

Two new fellowships to Alex Díaz and Cristina Castanyer, PhD researchers in training

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This week we have known that Alex Díaz has got the prestigious FPU fellowship of the Spanish Ministerio de Educación and Cristina Castanyer has got the FPI fellowship that the Spanish Ministerio de Ciencia awarded to the project CTQ2017-85341-P lead by Anna Pla and Miquel Solà. Alex Díaz is already a research in training supervised by Anna Pla and Anna Roglans and he is working on cyclization reactions catalized by Rh carbenes. Cristina Castanyer will start her PhD supervised by Anna Pla and Miquel Solà and she will work on [2+2+2] cycloadditions to fullerenes.

Congratulations to Àlex and Cristina!

Angew. Chem. Int. Ed. Inside Cover describing the first All-fullerene Electron Donor-Acceptor Conjugates

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Photoinduced electron transfer (PET) is a general nature occurring process which is related with the photosynthetic process. Scientists have always been interested in mimicking this process from artificial molecules in the search for controlling and tuning this process for practical purposes. The appropriate molecules and materials have been an important task in science. The aforementioned mimicking of the photosynthetic process requires the presence of appropriate electron donor molecules interacting (covalently or supramolecularly) with electron acceptor molecules. Light irradiation promotes the electron transfer from the donor to the acceptor units. Fullerenes are amazing ball-shape molecules formed exclusively by carbon atoms which are known to exhibit interesting electron accepting properties. Therefore, they have been extensively used in Donor-Acceptor systems.

A group of chemists from the Universidad Complutense de Madrid lead by Prof. Nazario Martín together with a group of researchers from the Friederich-Alexander Univesität Erlangen-Nürnberg lead by Dirk M. Guldi, and the DiMoCat members Antony J. Stasyuk, Olga A. Stasyuk, Alexander A. Voityuk, and Miquel Solà have shown the first example in which fullerenes, depending on their features, are able to act as acceptor but also as donor components in artificial photosynthetic systems. Furthermore, they have described the first example in which light irradiation promotes de electron transfer from the donor Lu3N@C80 to the acceptor C60 giving rise to a charge separated state involving two fullerene cages!

The paper has been published in Angew. Chem. Int. Ed. And can be found in the following link Angew. Chem. Int. Ed., 58 (2019) 6932-6937. The inside cover of the issue has been dedicated to this work:

Generation of H2 by an Environmental Friendly Mn-Catalyzed Reaction

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A pure computational paper by the DIMOCAT team of IQCC has been undertaken to favour the generation of H2  , once known experimentally by Milstein and coworkers that Mn-pincer could catalyze the acceptorless dehydrogenative coupling of nitriles and alcohols to yield acrylonitriles. The reaction mechanism proposed in that work contained some intermediates that, in most of the cases, were not characterized. Moreover, one of the intermediates involved a charged separation, which is unlikely in apolar solvents. To clarify the reaction mechanism of this critical reaction, a DFT study was performed. Results prove the existence of a cooperative effect of the metal and the ligand in several steps of the catalytic cycle. It is unveiled the presence of several equilibria between isomeric intermediates where water, or the same alcohol reagent, takes part in assisting the proton transfer. Furthermore, the charge-separated structure proposed experimentally turned out to be a nearly pure covalent bond between the two expected charged moieties. More importantly catalytically speaking, the Knoevenagel condensation step that generates the acrylonitrile is found to be the rate-determining step.

J. A. Luque-Urrutia, M. Solà, D. Milstein, and A. Poater

“Mechanism of the Manganese-Pincer Catalyzed Acceptorless Dehydrogenative Coupling of Nitriles and Alcohols”

J. Am. Chem. Soc. 2019, ASAP, accepted

DOI: 10.1021/jacs.8b11308