Femtosecond extreme ultraviolet spectroscopy of an iridium photocatalyst reveals oxidation state and ligand field specific dynamics

02 November 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


Femtosecond X-ray absorption spectroscopy at the Ir O3-edge and N6,7-edges is performed on the photocatalyst iridium(III) tris(2-phenylpyridine), Ir(III)(ppy)3 using a tabletop high-harmonic source. Extreme ultraviolet (XUV) absorption between 44 eV and 72 eV measures transitions from the Ir 5p3/2 and 4f5/2,7/2 core to 5d valence orbitals, and the position of these spectral features is shown to be sensitive to the oxidation state and ligand field of the metal center. Upon excitation of the singlet metal-to-ligand charge transfer (1MLCT) band at 400 nm, a shift in the spectra due to the formation of the Ir(IV) center is observed, as is the creation of a new spectral feature corresponding to transitions into the t2g hole. Vibrational cooling of the MLCT state on the 3 ps and 16 ps timescales is measured as changes in the intensity of the transient features. This work establishes XUV spectroscopy as a useful tool for measuring the electronic structure of 3rd row transition metal photosensitizers and catalysts at ultrafast timescales.


extreme ultraviolet
high-harmonic generation


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.