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Title: Ligand manipulation of charge transfer excited state relaxation and spin crossover in [Fe(2,2'-bipyridine) 2(CN) 2]

Here, we have used femtosecond resolution UV-visible and Kβ x-ray emission spectroscopy to characterize the electronic excited state dynamics of [Fe(bpy) 2(CN) 2], where bpy=2,2'-bipyridine, initiated by metal-to-ligand charge transfer (MLCT) excitation. The excited-state absorption in the transient UV-visible spectra, associated with the 2,2'-bipyridine radical anion, provides a robust marker for the MLCT excited state, while the transient Kβ x-ray emission spectra provide a clear measure of intermediate and high spin metal-centered excited states. From these measurements, we conclude that the MLCT state of [Fe(bpy) 2(CN) 2] undergoes ultrafast spin crossover to a metal-centered quintet excited state through a short lived metal-centered triplet transient species. These measurements of [Fe(bpy) 2(CN) 2] complement prior measurement performed on [Fe(bpy) 3] 2+ and [Fe(bpy)(CN) 4] 2– in dimethylsulfoxide solution and help complete the chemical series [Fe(bpy) N(CN) 6–2N] 2N-4, where N = 1–3. The measurements confirm that simple ligand modifications can significantly change the relaxation pathways and excited state lifetimes and support the further investigation of light harvesting and photocatalytic applications of 3 d transition metal complexes.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [5] ;  [6] ;  [7] ;  [3] ;  [8] ;  [3] ;  [6] ;  [9] ;  [10] ;  [3] ;  [11] ;  [3] ;  [12] ;  [13] ;  [3] more »;  [9] ;  [9] ;  [9] ;  [14] « less
  1. Stanford Univ., Menlo Park, CA (United States); Technical Univ. of Denmark, Lyngby (Denmark); Lund Univ., Lund (Sweden)
  2. Stanford Univ., Menlo Park, CA (United States); Beijing Normal Univ., Beijing (China)
  3. SLAC National Accelerator Lab., Menlo Park, CA (United States)
  4. Stanford Univ., Menlo Park, CA (United States)
  5. Stanford Univ., Stanford, CA (United States)
  6. Stanford Univ., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  7. Technical Univ. of Denmark, Lyngby (Denmark); Lund Univ., Lund (Sweden)
  8. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Max Planck Institute for Biophysical Chemistry, Gottingen (Germany)
  9. Lund Univ., Lund (Sweden)
  10. Technical Univ. of Denmark, Lyngby (Denmark)
  11. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  12. Technical Univ. of Denmark, Lyngby (Denmark); SLAC National Accelerator Lab., Menlo Park, CA (United States)
  13. HPSTAR, Shanghai (China)
  14. Stanford Univ., Menlo Park, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-76SF00515; AMOS program within the Chemical Sciences, Geosciences, and Biosciences Division of the Office of Ba
Type:
Accepted Manuscript
Journal Name:
Structural Dynamics
Additional Journal Information:
Journal Volume: 4; Journal Issue: 4; Journal ID: ISSN 2329-7778
Publisher:
American Crystallographic Association/AIP
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1362282
Alternate Identifier(s):
OSTI ID: 1366564