A Caltech Library Service

Tracking excited-state charge and spin dynamics in iron coordination complexes

Zhang, Wenkai and Alonso-Mori, Roberto and Bergmann, Uwe and Bressler, Christian and Chollet, Matthieu and Galler, Andreas and Gawelda, Wojciech and Hadt, Ryan G. and Hartsock, Robert W. and Kroll, Thomas and Kjær, Kasper S. and Kubiček, Katharina and Lemke, Henrik T. and Liang, Huiyang W. and Meyer, Drew A. and Nielsen, Martin M. and Purser, Carola and Robinson, Joseph S. and Solomon, Edward I. and Sun, Zheng and Sokaras, Dimosthenis and van Driel, Tim B. and Vankó, György and Weng, Tsu-Chien and Zhu, Diling and Gaffney, Kelly J. (2014) Tracking excited-state charge and spin dynamics in iron coordination complexes. Nature, 509 (7500). pp. 345-348. ISSN 0028-0836. PMCID PMC5668134. doi:10.1038/nature13252.

[img] PDF - Accepted Version
See Usage Policy.

[img] Image (JPEG) (Extended Data Figure 1 : Experimental and calculated Kβ fluorescence spectra for triplet spin states) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Figure 2 : Time-dependent Kβ fluorescence spectra and fit using the sequential kinetic model with a triplet transient) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Figure 3 : Time-dependent Kβ fluorescence spectra and fit using the direct kinetic model without a triplet transient.) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Figure 4 : The 50 fs time delay normalized Kβ fluorescent amplitude difference spectrum (ΔI) and kinetic model fit plotted as a function of X-ray emission energy) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Figure 5 : Absorption spectrum and pump power dependence measurements) - Supplemental Material
See Usage Policy.

[img] Image (JPEG) (Extended Data Table 1: Fitted model parameters) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Crucial to many light-driven processes in transition metal complexes is the absorption and dissipation of energy by 3d electrons. But a detailed understanding of such non-equilibrium excited-state dynamics and their interplay with structural changes is challenging: a multitude of excited states and possible transitions result in phenomena too complex to unravel when faced with the indirect sensitivity of optical spectroscopy to spin dynamics and the flux limitations of ultrafast X-ray sources. Such a situation exists for archetypal polypyridyl iron complexes, such as [Fe(2,2'-bipyridine)_3]^(2+), where the excited-state charge and spin dynamics involved in the transition from a low- to a high-spin state (spin crossover) have long been a source of interest and controversy. Here we demonstrate that femtosecond resolution X-ray fluorescence spectroscopy, with its sensitivity to spin state, can elucidate the spin crossover dynamics of [Fe(2,2'-bipyridine)_3]^(2+) on photoinduced metal-to-ligand charge transfer excitation. We are able to track the charge and spin dynamics, and establish the critical role of intermediate spin states in the crossover mechanism. We anticipate that these capabilities will make our method a valuable tool for mapping in unprecedented detail the fundamental electronic excited-state dynamics that underpin many useful light-triggered molecular phenomena involving 3d transition metal complexes.

Item Type:Article
Related URLs:
URLURL TypeDescription ReadCube access CentralArticle
Bergmann, Uwe0000-0001-5639-166X
Hadt, Ryan G.0000-0001-6026-1358
Solomon, Edward I.0000-0003-0291-3199
Additional Information:© 2014 Macmillan Publishers Limited. Received 7 May 2013; accepted 6 March 2014. Published online 7 May 2014. We thank P. Frank, B. Lin and S. DeBeer for discussion, S. DeBeer for some model iron complex X-ray fluorescence spectra, and D. Stanbury for providing some iron complexes. Experiments were carried out at LCLS and SSRL, which are National User Facilities operated for DOE and OBES respectively by Stanford University. W.Z., R.W.H., H.W.L., D.A.M., Z.S. and K.J.G. acknowledge support from the AMOS programme within the Chemical Sciences, Geosciences and Biosciences Division of the Office of Basic Energy Sciences, Office of Science, US Department of Energy. E.I.S. acknowledges support from the NSF (CHE-0948211). R.G.H. acknowledges a Gerhard Casper Stanford Graduate Fellowship and the Achievements Rewards for College Scientists (ARCS) Foundation. T.K. acknowledges the German Research Foundation (DFG), grant KR3611/2-1. K.S.K., M.M.N. and T.B.v.D. acknowledge support from the Danish National Research Foundation and from DANSCATT. K.K. thanks the Volkswagen Foundation for support under the Peter Paul Ewald fellowship program (I/85832). G.V. acknowledges support from the European Research Council (ERC-StG-259709) and the Lendület Programme of the Hungarian Academy of Sciences. C.B., W.G. and A.G. thank the DFG (SFB925), as well as the European XFEL, for financial support. Author Contributions: W.Z., R.A.-M., U.B., R.W.H., D.A.M., T.-C.W. and K.J.G. designed the experiment. W.Z., R.A.-M., U.B., M.C., R.W.H., K.S.K., K.K., H.T.L., H.W.L., C.P., J.S.R., Z.S., D.S., T.B.v.D., T.-C.W., D.Z. and K.J.G. did the experiment. W.Z., T.K., K.S.K., T.B.v.D., G.V. and T.-C.W. analysed the data. W.Z., R.A.-M., U.B., C.B., W.G., A.G., R.G.H., R.W.H., T.K., K.S.K., K.K., D.A.M., M.M.N., E.I.S., D.S. and K.J.G. wrote the manuscript. The authors declare no competing financial interests.
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Stanford UniversityUNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)KR3611/2-1
Danish National Research FoundationUNSPECIFIED
Volkswagen StiftungI/85832
European Research Council (ERC)259709
Hungarian Academy of SciencesLendület Programme
Deutsche Forschungsgemeinschaft (DFG)SFB 925
Issue or Number:7500
PubMed Central ID:PMC5668134
Record Number:CaltechAUTHORS:20180612-112437637
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87006
Deposited By: George Porter
Deposited On:12 Jun 2018 18:45
Last Modified:15 Nov 2021 20:44

Repository Staff Only: item control page