Revisiting the photochemical synthesis of [FeFe]-hydrogenase mimics: reaction optimization, mechanistic study and electrochemical behaviour

Sergio Aguado; Luis Casarrubios; Carmen Ramírez de Arellano; Miguel A Sierra

doi:10.1039/d0ra06002j

Revisiting the photochemical synthesis of [FeFe]-hydrogenase mimics: reaction optimization, mechanistic study and electrochemical behaviour

RSC Adv. 2020 Aug 12;10(50):29855-29867. doi: 10.1039/d0ra06002j. eCollection 2020 Aug 10.

Authors

Sergio Aguado¹, Luis Casarrubios¹, Carmen Ramírez de Arellano², Miguel A Sierra¹

Affiliations

¹ Departamento de Química Orgánica, Facultad de Ciencias Químicas, Center for Innovation in Advanced Chemistry (ORFEO-CINQA), Universidad Complutense 28040-Madrid Spain sierraor@ucm.es lcasarru@ucm.es.
² Departamento de Química Orgánica, Center for Innovation in Advanced Chemistry (ORFEO-CINQA), Universidad de Valencia 46100-Valencia Spain.

Abstract

The photoreaction of [(μ-S)₂Fe₂(CO)₆] and alkenes or alkynes has been optimized to readily obtain functionalized [FeFe]-hydrogenase mimics. Irradiation under low CO pressure in THF produces the corresponding photo-adducts in good/acceptable (alkenes/alkynes) yields, with retention of the starting olefin stereochemistry. DFT-calculations provide plausible reaction pathways in both, singlet and triplet states. The DFT-calculation based in the singlet state is energetically more favorable. The electrochemical behavior of the synthesized compounds is also presented, including studies in acidic media. The electrochemical properties of the products vary in the presence of a double bond (cycloaddition of [(μ-S)₂Fe₂(CO)₆] to alkynes), respect to a single bond (cycloaddition to alkenes).