Ultrafast spin crossover photochemical mechanism in [Fe(2,2'−bipyridine)3]2+ revealed by quantum dynamics

10 March 2023, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


The role of triplet intermediates in the photoinduced spin crossover reaction of [FeII(2,2'-bipyridine)3]2+ is still under debate. Employing quantum dynamics, we show that the metal-centered (MC) triplets are responsible for the transfer to the quintet high-spin state. This photochemical pathway is made possible thanks to bipyridine stretching vibrations, facilitating the transfer between the initial metal-ligand charge transfer (MLCT) states to the MC triplets. These results show the central role of ligands in modulating the excited state spectrum and the photochemical mechanism, opening the route for increased metal-centered lifetime that increases the effciency of iron-based photocatalysts.


ferrous complexes
quantum dynamics
spin crossover

Supplementary materials

Supporting information
The file contains the computational details, geometries, excited state analysis, model hamiltonian parameters, quantum dynamics, and the fitting procedure for extracting the first-order kinetic models.


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.