Excited‐State Kinetics of an Air‐Stable Cyclometalated Iron(II) Complex. Issue 51 (26th June 2019)

• Record Type: Journal Article
• Authors: Steube, Jakob; Burkhardt, Lukas; Päpcke, Ayla; Moll, Johannes; Zimmer, Peter; Schoch, Roland; Wölper, Christoph; Heinze, Katja; Lochbrunner, Stefan; Bauer, Matthias
• Is Part Of: Chemistry. Volume 25:Issue 51(2019)
• Page Start: 11826
• Page End: 11830
• Publication Date: 2019-06-26
• Subjects: iron -- photochemistry -- excited-state kinetics -- transient absorption spectroscopy -- DFT calculations; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201902488
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: The complex class [Fe(N^N^C)(N^N^N)] + with an Earth‐abundant metal ion has been repeatedly suggested as a chromophore and potential photosensitizer on the basis of quantum chemical calculations. Synthesis and photophysical properties of the parent complex [Fe(pbpy)(tpy)] + (Hpbpy=6‐phenyl‐2, 2′‐bipyridine and tpy=2, 2′:6′, 2′′‐terpyridine) of this new chromophore class are now reported. Ground‐state characterization by X‐ray diffraction, electrochemistry, spectroelectrochemistry, UV/Vis, and X‐ray spectroscopy in combination with DFT calculations proves the high impact of the cyclometalating ligand on the electronic structure. The photophysical properties are significantly improved compared to the prototypical [Fe(tpy)2 ] 2+ complex. In particular, the metal‐to‐ligand absorption extends into the near‐IR and the 3 MLCT lifetime increases by 5.5, whereas the metal‐centered excited triplet state is very short‐lived. Abstract : DFT calculations : Cyclometalated iron complexes have been suggested as potent chromophores based on theoretical investigations. Herein, the impact of cyclometalation on the ground and excited state is experimentally shown for the first time with the complex [Fe(pbpy)(tpy)] + (Hpbpy=6‐phenyl‐2, 2′‐bipyridine and tpy=2, 2′:6′, 2′′‐terpyridine; see figure) of [Fe(C^N^N)(N^N^N)] + in comparison to [Fe(tpy)2 ] 2+ .