Modulations of a Metal-Ligand Interaction and Photophysical Behaviors by Hückel-Möbius Aromatic Switching

Jinseok Kim, Juwon Oh, Seongchul Park, Tomoki Yoneda, Atsuhiro Osuka, Manho Lim, Dongho Kim

Research output: Contribution to journalArticlepeer-review

Abstract

In organometallic complexes containing π-conjugated macrocyclic chelate ligands, conformational change significantly affects metal-ligand electronic interactions, hence tuning properties of the complexes. In this regard, we investigated the metal-ligand interactions in hexaphyrin mono-Pd(II) complexes Pd[28]M and Pd[26]H, which exhibit a redox-induced switching of Hückel-Möbius aromaticity and subsequent molecular conformation, and their effect on the electronic structure and photophysical behaviors. In Möbius aromatic Pd[28]M, the weak metal-ligand interaction leads to the πelectronic structure of the hexaphyrin ligand remaining almost intact, which undergoes efficient intersystem crossing (ISC) assisted by the heavy-atom effect of the Pd metal. In Hückel aromatic Pd[26]H, the significant metal-ligand interaction results in ligand-to-metal charge-transfer (LMCT) in the excited-state dynamics. These contrasting metal-ligand electronic interactions have been revealed by time-resolved electronic and vibrational spectroscopies and time-dependent DFT calculations. This work indicates that the conspicuous modulation of metal-ligand interaction by Hückel-Möbius aromaticity switching is an appealing approach to manipulate molecular properties of metal complexes, further enabling the fine-tuning of metal-ligand interactions and the novel design of functional organometallic materials.

Original languageEnglish
Pages (from-to)582-589
Number of pages8
JournalJournal of the American Chemical Society
Volume144
Issue number1
DOIs
Publication statusPublished - 2022 Jan 12

Bibliographical note

Funding Information:
The work at Yonsei University was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIT) (Grant 2021R1A2C300630811). The quantum calculations were performed with the supercomputing resources of the Korea Institute of Science and Technology Information. The work at Pusan National University was supported by an NRF grant funded by the Korea Government (MEST) (Grant NRF-2020R1A2B5B01001934). The work at Kyoto was supported by JSPS KAKENHI Grant JP18H03910. The work at Soonchunhyang University was supported by the Soonchunhyang University Research Fund and National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIT) (Grants 2021R1C1C1013828 and 2021R1A6A1A03039503).

Publisher Copyright:
© 2021 American Chemical Society.

All Science Journal Classification (ASJC) codes

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

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