Excited-State Switching in Rhenium(I) Bipyridyl Complexes with Donor-Donor and Donor-Acceptor Substituents

Joshua J. Sutton, Dan Preston, Philipp Traber, Johannes Steinmetzer, Xue Wu, Surajit Kayal, Xue Z. Sun, James D. Crowley, Michael W. George, Stephan Kupfer, Keith C. Gordon

Research output: Journal PublicationArticlepeer-review

5 Citations (Scopus)

Abstract

The optical properties of two Re(CO)3(bpy)Cl complexes in which the bpy is substituted with two donor (triphenylamine, TPA, ReTPA2) as well as both donor (TPA) and acceptor (benzothiadiazole, BTD, ReTPA-BTD) groups are presented. For ReTPA2 the absorption spectra show intense intraligand charge-transfer (ILCT) bands at 460 nm with small solvatochromic behavior; for ReTPA-BTD the ILCT transitions are weaker. These transitions are assigned as TPA → bpy transitions as supported by resonance Raman data and TDDFT calculations. The excited-state spectroscopy shows the presence of two emissive states for both complexes. The intensity of these emission signals is modulated by solvent. Time-resolved infrared spectroscopy definitively assigns the excited states present in CH2Cl2 to be MLCT in nature, and in MeCN the excited states are ILCT in nature. DFT calculations indicated this switching with solvent is governed by access to states controlled by spin-orbit coupling, which is sufficiently different in the two solvents, allowing to select out each of the charge-transfer states.

Original languageEnglish
Pages (from-to)9082-9093
Number of pages12
JournalJournal of the American Chemical Society
Volume143
Issue number24
DOIs
Publication statusPublished - 23 Jun 2021

ASJC Scopus subject areas

  • Catalysis
  • Chemistry (all)
  • Biochemistry
  • Colloid and Surface Chemistry

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