Ultrafast high spin→low spin photo-switching of an isolated [FeL2][BF4]2 spin-crossover complex at room temperature

Beşe D., Gürpınar K., Uzay Karakaya E., Akca F. G., NAZIR H., EMRE Ş. B., ...Daha Fazla

Optical Materials, cilt.159, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 159
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.optmat.2024.116588
  • Dergi Adı: Optical Materials
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Applied Science & Technology Source, Chimica, Communication Abstracts, Compendex, Computer & Applied Sciences, INSPEC
  • Anahtar Kelimeler: Ligand field states, Photo switching, Reverse LIESST, spin crossover, Ultrafast spectroscopy
  • Ankara Üniversitesi Adresli: Evet

Özet

The role of ligand field (LF) states in photo-physics of reverse light-induced excited spin state trapping (reverse-LIESST) effect of an Iron (II) spin-crossover (SCO) complex was demonstrated experimentally in solution, at room temperature by using ultrafast transient absorption spectroscopy technique. We showed that selective photo switching between high spin (HS) and low-spin (LS) states, i.e. HS→HS or HS→LS transitions, is possible by photo excitation from HS ground state to the HS∗ metal–ligand charge transfer (MLCT) states (at 400 nm pumping) or to ligand-field (LF) state (at 435 nm pumping), respectively. This is an effective direct observation of reverse-LIESST effect through LF state pumping in solution at room temperature. We have proposed different relaxation pathways along with the ultrafast relaxation time components that account for HS→HS and HS→LS transitions.