Dipartimento di Chimica

 

 

Abstract

The most active cobalt-based catalysts for light-driven hydrogen evolution are usually based on hexacoordinate polypyridine complexes with a distorted octahedral structure. (1,2) We have challenged this paradigm by developing cobalt complexes based on a hexadentate polypyridyl ligand, which show an exotic heptacoordinate structure and outstanding performances with respect to their hexacoordinate counterparts. (3,4) In this talk the results of our investigations concerning the optimizations of such a class of catalysts are presented (Figure 1). In particular, the effect of the introduction of electron-donating and electron-withdrawing groups (aimed at haltering the ligand electronic properties) will be discussed and compared with the effect of the presence of groups potentially acting as proton relay units. (5,6) The impact of the variation of the electron transfer kinetic, deriving from the use of milder photochemically-generated reducing agents, will be also discussed. (7) The aim of this talk is to provide an overview of the structureactivity investigation of this class of catalysts, providing new insights for the design of more efficient hydrogen evolution catalysts.

 

References

1. Queyriaux, N.; Jane, R. T.; Massin, J.; Artero, V.; Chavarot-Kerlidou, M., Recent Developments in Hydrogen Evolving Molecular Cobalt(II)-Polypyridyl Catalysts. Coord. Chem. Rev. 2015, 304-305, 3-19.

2. Droghetti, F.; Lucarini, F.; Molinari, A.; Ruggi, A.; Natali, M., Recent findings and future directions in photosynthetic hydrogen evolution using polypyridine cobalt complexes. Dalton Trans. 2022, 51 (28), 10658- 10673.

3. Lucarini, F.; Fize, J.; Morozan, A.; Marazzi, M.; Natali, M.; Pastore, M.; Artero, V.; Ruggi, A., Insights into the mechanism of photosynthetic H2 evolution catalyzed by a heptacoordinate cobalt complex. Sustainable Energy Fuels 2020, 4 (2), 589-599.

4. Lucarini, F.; Pastore, M.; Vasylevskyi, S.; Varisco, M.; Solari, E.; Crochet, A.; Fromm, K. M.; Zobi, F.; Ruggi, A., Heptacoordinate Co-II Complex: A New Architecture for Photochemical Hydrogen Production. Chem. Eur. J. 2017, 23 (28), 6768-6771.

5. Lucarini, F.; Bongni, D.; Schiel, P.; Bevini, G.; Benazzi, E.; Solari, E.; Fadaei-Tirani, F.; Scopelliti, R.; Marazzi, M.; Natali, M.; Pastore, M.; Ruggi, A., Rationalizing Photo-Triggered Hydrogen Evolution Using Polypyridine Cobalt Complexes: Substituent Effects on Hexadentate Chelating Ligands. ChemSusChem 2021, 14 (8), 1874-1885.

6. Lucarini, F.; Fize, J.; Morozan, A.; Droghetti, F.; Solari, E.; Tirani, F. F.; Scopelliti, R.; Marazzi, M.; Natali, M.; Pastore, M.; Artero, V.; Ruggi, A., Electro- and photochemical H2 generation by Co(II) polypyridylbased catalysts bearing ortho-substituted pyridines. Sustainable Energy Fuels 2023, 10.1039/D3SE00295K7.

7. Orlando, A.; Lucarini, F.; Benazzi, E.; Droghetti, F.; Ruggi, A.; Natali, M., Rethinking Electronic Effects in Photochemical Hydrogen Evolution Using CuInS2@ ZnS Quantum Dots Sensitizers. Molecules 2022, 27 (23), 8277.

 

Dr. Albert Ruggi 

Albert Ruggi achieved his M. Sc. in Organic chemistry (cum laude) in 2006 at the University of Rome “La Sapienza”. In 2011 he obtained his Ph.D. in Chemistry at the University of Twente (The Netherlands) where he worked under the supervision of Prof. David N. Reinhoudt and Prof. Aldrik H. Velders on the design of transition metal complexes with tailored optical properties. He then moved to the EPFL (Switzerland) where he worked as Post-doc in the group of Prof. Kay Severin. In 2013 he was appointed as Maître-assistant (Lecturer) at the University of Fribourg (Switzerland) and he started his independent research group. In 2021 he has been promoted Maître d’enseignement et de recherche (Senior Lecturer) in the same University. His research interests are mainly focused on the development of catalysts based on earthabundant transition metal complexes for the photochemical and electrochemical generation of solar fuels such as hydrogen and CO2 reduction products. He is the author of 37 articles (Hindex 19) and of 1 book chapter.