Reactions of Super Reductants and Oxidants Explored by Ultrafast Spectroscopy

2022 Fiscal Year Annual Research Report

• Project/Area Number: 19K21127
• Research Institution: Osaka University
• Principal Investigator: LU CHAO 大阪大学, 産業科学研究所, 助教 (90828112)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: Excited Ions / Electron Transfer / Laser Flash Photolysis / Physical Chemistry / Photochemistry

Outline of Annual Research Achievements

In the current research, the unprecedented properties and various electron transfer processes caused by excited ion species as the super redox initiators were investigated. The purposes of this research are the clarification of excited-state/reaction dynamics of novel excited ions and the exploration of their application for various molecular systems to establish a new science field of photochemistry.
Hoop-shaped macrocycles such as cycloparaphenylenes (CPPs) have attracted considerable attention because of their unique properties. In this study, the excited states of CPP2+ were investigated by transient absorption measurements.
Aromatic diimides, especially naphthalenediimide (NDI) is among the most widely explored components for n-type semiconductor materials. In this study, xanthene holds NDI and electron acceptors at van der Waals distances to realize strong π-π interaction between them. By applying femtosecond laser flash photolysis, an investigation was conducted to exhibit the electron transfer from excited NDI radical anion in intensely interacting systems.
Fullerene anions have attracted wide interest due to their connection with relevant performances such as the conductivity of the doped molecular devices. Thus, in the current study, C60, C60 derivative as pyrrolidino[60]fullerene (C60H), and the dyads as C60-NDI and C60-pyromellitimide (PI) were prepared as the targets. For the first time, the femtosecond transient absorption spectroscopy was employed to directly describe the excited states and photo-induced electron transfer of fullerene dianions.