Long‐lived Charge‐Transfer State in Spiro Compact Electron Donor‐Acceptor Dyads Based on Pyromellitimide‐Derived Rhodamine: Charge Transfer Dynamics and Electron Spin Polarization

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Chen X., Sukhanov A. A., Yan Y., Bese D., Bese Ç., Zhao J., ...More

Angewandte Chemie-International Edition, vol.61, no.33, 2022 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 61 Issue: 33
  • Publication Date: 2022
  • Doi Number: 10.1002/anie.202203758
  • Journal Name: Angewandte Chemie-International Edition
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, L'Année philologique, Agricultural & Environmental Science Database, Applied Science & Technology Source, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Chimica, Compendex, EMBASE, MEDLINE, Veterinary Science Database
  • Keywords: Charge Transfer, Charge-Separated State, Electron Transfer, Intersystem Crossing, Triplet State, RADICAL-ION PAIRS, MOLECULAR DESIGN, SEPARATED STATE, TRIPLET-STATE, RECOMBINATION, PHOTOSENSITIZERS, FLUORESCENT, LIFETIME, ENERGY, TRIAD
  • Open Archive Collection: AVESIS Open Access Collection
  • Hacettepe University Affiliated: Yes

Abstract

We observed a long-lived charge transfer (CT) state in a novel orthogonal compact electron donor-acceptor dyads, with closed form of rhodamine (Rho) as electron donor and pyromellitimide (PI),or thionated PI, as electron acceptor. The two parts in the dyads are connected via a spiro quaternary carbon atom, thus the torsion between the donor and acceptor is completely inhibited, which is beneficial to reduce the reorganization energy and to exploit the Marcus inverted region effect to prolong the CT state lifetime. Femtosecond transient absorption spectra show that the charge separation is rather fast, while nanosecond transient absorption spectra confirmed the formation of long-lived CT state (2.6 mu s). Time-resolved electron paramagnetic resonance (TREPR) spectra determined the spin multiplicity of the long living state and assigned it to a (CT)-C-3 state. Replacement of an oxygen atom in the PI part with a sulfur atom favoring classical intersystem crossing processes, causes a consistently shortening of the lifetime of the (CT)-C-3 state (0.29 mu s).