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

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

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.

Citation

Sutton, J. J., Preston, D., Traber, P., Steinmetzer, J., Wu, X., Kayal, S., …Gordon, K. C. (2021). Excited-State Switching in Rhenium(I) Bipyridyl Complexes with Donor-Donor and Donor-Acceptor Substituents. Journal of the American Chemical Society, 143(24), 9082-9093. https://doi.org/10.1021/jacs.1c02755

• Journal Article Type: Article
• Acceptance Date: Mar 13, 2021
• Online Publication Date: Jun 11, 2021
• Publication Date: Jun 23, 2021
• Deposit Date: Sep 13, 2021
• Publicly Available Date: Jun 12, 2022
• Journal: Journal of the American Chemical Society
• Print ISSN: 0002-7863
• Electronic ISSN: 1520-5126
• Publisher: American Chemical Society (ACS)
• Peer Reviewed: Peer Reviewed
• Volume: 143
• Issue: 24
• Pages: 9082-9093
• DOI: https://doi.org/10.1021/jacs.1c02755
• Keywords: Colloid and Surface Chemistry; Biochemistry; General Chemistry; Catalysis
• Public URL: https://nottingham-repository.worktribe.com/output/5670444
• Publisher URL: https://pubs.acs.org/doi/10.1021/jacs.1c02755
• Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society copyright© American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/jacs.1c02755