Is Iron the New Ruthenium?

Wenger, Oliver S.. (2019) Is Iron the New Ruthenium? Chemistry - A European Journal, 25 (24). pp. 6043-6052.

PDF - Accepted Version

Official URL: https://edoc.unibas.ch/73098/

Downloads: Statistics Overview


Ruthenium complexes with polypyridine ligands are very popular choices for applications in photophysics and photochemistry, for example, in lighting, sensing, solar cells, and photoredox catalysis. There is a long‐standing interest in replacing ruthenium with iron because ruthenium is rare and expensive, whereas iron is comparatively abundant and cheap. However, it is very difficult to obtain iron complexes with an electronic structure similar to that of ruthenium(II) polypyridines. The latter typically have a long‐lived excited state with pronounced charge‐transfer character between the ruthenium metal and ligands. These metal‐to‐ligand charge‐transfer (MLCT) excited states can be luminescent, with typical lifetimes in the range of 100 to 1000 ns, and the electrochemical properties are drastically altered during this time. These properties make ruthenium(II) polypyridine complexes so well suited for the abovementioned applications. In iron(II) complexes, the MLCT states can be deactivated extremely rapidly (ca. 50 fs) by energetically lower lying metal‐centered excited states. Luminescence is then no longer emitted, and the MLCT lifetimes become much too short for most applications. Recently, there has been substantial progress on extending the lifetimes of MLCT states in iron(II) complexes, and the first examples of luminescent iron complexes have been reported. Interestingly, these are iron(III) complexes with a completely different electronic structure than that of commonly targeted iron(II) compounds, and this could mark the beginning of a paradigm change in research into photoactive earth‐abundant metal complexes. After outlining some of the fundamental challenges, key strategies used so far to enhance the photophysical and photochemical properties of iron complexes are discussed and recent conceptual breakthroughs are highlighted in this invited Concept article.
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Anorganische Chemie (Wenger)
UniBasel Contributors:Wenger, Oliver
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
edoc DOI:
Last Modified:01 Jul 2020 12:49
Deposited On:16 Dec 2019 10:39

Repository Staff Only: item control page