Binding of Scandium Ions to Metalloporphyrin?Flavin Complexes for Long-Lived Charge Separation

• KOJIMA, Takahiko

• Kobayashi, Ryosuke

• ISHIZUKA, Tomoya

• Yamakawa, Shinya

• KOTANI, Hiroaki

• Nakanishi, Tatsuaki

• Ohkubo, Kei

• Shiota, Yoshihito

• Yoshizawa, Kazunari

• Fukuzumi, Shunichi

Bibliographic Information

Other Title

• Binding of Scandium Ions to Metalloporphyrin–Flavin Complexes for Long‐Lived Charge Separation

Abstract

A porphyrin–flavin‐linked dyad and its zinc and palladium complexes (MPorFl: 2 M, M=2 H, Zn, and Pd) were newly synthesized and the X‐ray crystal structure of 2 Pd was determined. The photodynamics of 2 M were examined by femto‐ and nanosecond laser flash photolysis measurements. Photoinduced electron transfer (ET) in 2 H 2 occurred from the singlet excited state of the porphyrin moiety (H 2 Por) to the flavin (Fl) moiety to produce the singlet charge‐separated (CS) state 1 (H 2 Por .+ Fl .− ), which decayed through back ET (BET) to form 3 [H 2 Por]*Fl with rate constants of 1.2×10 10 and 1.2×10 9  s −1 , respectively. Similarly, photoinduced ET in 2 Pd afforded the singlet CS state, which decayed through BET to form 3 [PdPor]*Fl with rate constants of 2.1×10 11 and 6.0×10 10  s −1 , respectively. The rate constant of photoinduced ET and BET of 2 M were related to the ET and BET driving forces by using the Marcus theory of ET. One and two Sc 3+ ions bind to the flavin moiety to form the FlSc 3+ and Fl(Sc 3+ ) 2 complexes with binding constants of K 1 =2.2×10 5   M −1 and K 2 =1.8×10 3   M −1 , respectively. Other metal ions, such as Y 3+ , Zn 2+ , and Mg 2+ , form only 1:1 complexes with flavin. In contrast to 2 M and the 1:1 complexes with metal ions, which afforded the short‐lived singlet CS state, photoinduced ET in 2 Pd⋅⋅⋅Sc 3+ complexes afforded the triplet CS state ( 3 [PdPor .+ Fl .− (Sc 3+ ) 2 ]), which exhibited a remarkably long lifetime of τ =110 ms ( k BET =9.1 s −1 ).

Journal

• Chemistry : a European journal

  Chemistry : a European journal 20 (47), 15518-15532, 2014-11

  Wiley

Keywords

• General Chemistry
• Catalysis
• Organic Chemistry

Details

• CRID: 1050001202625273472
• NII Article ID: 120007136507
• NII Book ID: AA11076269
• DOI: 10.1002/chem.201403960
• ISSN: 15213765
• ISSN: 09476539
• HANDLE: 2241/00123022
• Web Site: https://tsukuba.repo.nii.ac.jp/records/32149
• Web Site: https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchem.201403960
• Web Site: http://onlinelibrary.wiley.com/wol1/doi/10.1002/chem.201403960/fullpdf
• Text Lang: en
• Article Type: journal article
• Data Source:
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  • Crossref
  • CiNii Articles
  • KAKEN