Photo-induced oxidation of a dinuclear Mn2 II,II complex to the Mn2 III,IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine

P. Huang, A. Magnuson, R. Lomoth, M. Abrahamsson, M. Tamm, L. Sun, B. Van Rotterdam, J. Park, Leif Hammarström, B. Åkermark, S. Styring

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

To model the structural and functional parts of the water oxidizing complex in Photosystem II, a dimeric manganese(II,II) complex (1) was linked to a ruthenium(II)tris-bipyridine (RuII(bpy)3) complex via a substituted L-tyrosine, to form the trinuclear complex 2 [J. Inorg. Biochem. 78 (2000) 15]. Flash photolysis of 1 and RuII(bpy)3 in aqueous solution, in the presence of an electron acceptor, resulted in the stepwise extraction of three electrons by RuIII(bpy)3 from the Mn2 II,II dimer, which then attained the Mn2 III,IV oxidation state. In a similar experiment with compound 2, the dinuclear Mn complex reduced the photo-oxidized Ru moiety via intramolecular electron transfer on each photochemical event. From EPR it was seen that 2 also reached the Mn2 III,IV state. Our data indicate that oxidation from the Mn2 II,II state proceeds stepwise via intermediate formation of Mn2 II,III and Mn2 III,III. In the presence of water, cyclic voltammetry showed an additional anodic peak beyond Mn2 II,III/III,III oxidation which was significantly lower than in neat acetonitrile. Assuming that this peak is due to oxidation to Mn2 III,IV, this suggests that water is essential for the formation of the Mn2 III,IV oxidation state. Compound 2 is a structural mimic of the water oxidizing complex, in that it links a Mn complex via a tyrosine to a highly oxidizing photosensitizer. Complex 2 also mimics mechanistic aspects of Photosystem II, in that the electron transfer to the photosensitizer is fast and results in several electron extractions from the Mn moiety.

Original languageEnglish
Pages (from-to)159-172
Number of pages14
JournalJournal of Inorganic Biochemistry
Volume91
Issue number1
DOIs
Publication statusPublished - Jul 25 2002

Fingerprint

Electrons
Oxidation
Photosensitizing Agents
Photosystem II Protein Complex
Water
Tyrosine
Ruthenium
Photolysis
Structural Models
Manganese
Dimers
Cyclic voltammetry
Paramagnetic resonance
Experiments

Keywords

  • Artificial photosynthesis
  • Bioinorganic chemistry
  • Electrochemistry
  • EPR spectroscopy
  • Manganese

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry

Cite this

Photo-induced oxidation of a dinuclear Mn2 II,II complex to the Mn2 III,IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine. / Huang, P.; Magnuson, A.; Lomoth, R.; Abrahamsson, M.; Tamm, M.; Sun, L.; Van Rotterdam, B.; Park, J.; Hammarström, Leif; Åkermark, B.; Styring, S.

In: Journal of Inorganic Biochemistry, Vol. 91, No. 1, 25.07.2002, p. 159-172.

Research output: Contribution to journalArticle

Huang, P. ; Magnuson, A. ; Lomoth, R. ; Abrahamsson, M. ; Tamm, M. ; Sun, L. ; Van Rotterdam, B. ; Park, J. ; Hammarström, Leif ; Åkermark, B. ; Styring, S. / Photo-induced oxidation of a dinuclear Mn2 II,II complex to the Mn2 III,IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine. In: Journal of Inorganic Biochemistry. 2002 ; Vol. 91, No. 1. pp. 159-172.
@article{662d6753c19741bb88b566bf1fbab79b,
title = "Photo-induced oxidation of a dinuclear Mn2 II,II complex to the Mn2 III,IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine",
abstract = "To model the structural and functional parts of the water oxidizing complex in Photosystem II, a dimeric manganese(II,II) complex (1) was linked to a ruthenium(II)tris-bipyridine (RuII(bpy)3) complex via a substituted L-tyrosine, to form the trinuclear complex 2 [J. Inorg. Biochem. 78 (2000) 15]. Flash photolysis of 1 and RuII(bpy)3 in aqueous solution, in the presence of an electron acceptor, resulted in the stepwise extraction of three electrons by RuIII(bpy)3 from the Mn2 II,II dimer, which then attained the Mn2 III,IV oxidation state. In a similar experiment with compound 2, the dinuclear Mn complex reduced the photo-oxidized Ru moiety via intramolecular electron transfer on each photochemical event. From EPR it was seen that 2 also reached the Mn2 III,IV state. Our data indicate that oxidation from the Mn2 II,II state proceeds stepwise via intermediate formation of Mn2 II,III and Mn2 III,III. In the presence of water, cyclic voltammetry showed an additional anodic peak beyond Mn2 II,III/III,III oxidation which was significantly lower than in neat acetonitrile. Assuming that this peak is due to oxidation to Mn2 III,IV, this suggests that water is essential for the formation of the Mn2 III,IV oxidation state. Compound 2 is a structural mimic of the water oxidizing complex, in that it links a Mn complex via a tyrosine to a highly oxidizing photosensitizer. Complex 2 also mimics mechanistic aspects of Photosystem II, in that the electron transfer to the photosensitizer is fast and results in several electron extractions from the Mn moiety.",
keywords = "Artificial photosynthesis, Bioinorganic chemistry, Electrochemistry, EPR spectroscopy, Manganese",
author = "P. Huang and A. Magnuson and R. Lomoth and M. Abrahamsson and M. Tamm and L. Sun and {Van Rotterdam}, B. and J. Park and Leif Hammarstr{\"o}m and B. {\AA}kermark and S. Styring",
year = "2002",
month = "7",
day = "25",
doi = "10.1016/S0162-0134(02)00394-X",
language = "English",
volume = "91",
pages = "159--172",
journal = "Journal of Inorganic Biochemistry",
issn = "0162-0134",
publisher = "Elsevier Inc.",
number = "1",

}

TY - JOUR

T1 - Photo-induced oxidation of a dinuclear Mn2 II,II complex to the Mn2 III,IV state by inter- and intramolecular electron transfer to RuIIItris-bipyridine

AU - Huang, P.

AU - Magnuson, A.

AU - Lomoth, R.

AU - Abrahamsson, M.

AU - Tamm, M.

AU - Sun, L.

AU - Van Rotterdam, B.

AU - Park, J.

AU - Hammarström, Leif

AU - Åkermark, B.

AU - Styring, S.

PY - 2002/7/25

Y1 - 2002/7/25

N2 - To model the structural and functional parts of the water oxidizing complex in Photosystem II, a dimeric manganese(II,II) complex (1) was linked to a ruthenium(II)tris-bipyridine (RuII(bpy)3) complex via a substituted L-tyrosine, to form the trinuclear complex 2 [J. Inorg. Biochem. 78 (2000) 15]. Flash photolysis of 1 and RuII(bpy)3 in aqueous solution, in the presence of an electron acceptor, resulted in the stepwise extraction of three electrons by RuIII(bpy)3 from the Mn2 II,II dimer, which then attained the Mn2 III,IV oxidation state. In a similar experiment with compound 2, the dinuclear Mn complex reduced the photo-oxidized Ru moiety via intramolecular electron transfer on each photochemical event. From EPR it was seen that 2 also reached the Mn2 III,IV state. Our data indicate that oxidation from the Mn2 II,II state proceeds stepwise via intermediate formation of Mn2 II,III and Mn2 III,III. In the presence of water, cyclic voltammetry showed an additional anodic peak beyond Mn2 II,III/III,III oxidation which was significantly lower than in neat acetonitrile. Assuming that this peak is due to oxidation to Mn2 III,IV, this suggests that water is essential for the formation of the Mn2 III,IV oxidation state. Compound 2 is a structural mimic of the water oxidizing complex, in that it links a Mn complex via a tyrosine to a highly oxidizing photosensitizer. Complex 2 also mimics mechanistic aspects of Photosystem II, in that the electron transfer to the photosensitizer is fast and results in several electron extractions from the Mn moiety.

AB - To model the structural and functional parts of the water oxidizing complex in Photosystem II, a dimeric manganese(II,II) complex (1) was linked to a ruthenium(II)tris-bipyridine (RuII(bpy)3) complex via a substituted L-tyrosine, to form the trinuclear complex 2 [J. Inorg. Biochem. 78 (2000) 15]. Flash photolysis of 1 and RuII(bpy)3 in aqueous solution, in the presence of an electron acceptor, resulted in the stepwise extraction of three electrons by RuIII(bpy)3 from the Mn2 II,II dimer, which then attained the Mn2 III,IV oxidation state. In a similar experiment with compound 2, the dinuclear Mn complex reduced the photo-oxidized Ru moiety via intramolecular electron transfer on each photochemical event. From EPR it was seen that 2 also reached the Mn2 III,IV state. Our data indicate that oxidation from the Mn2 II,II state proceeds stepwise via intermediate formation of Mn2 II,III and Mn2 III,III. In the presence of water, cyclic voltammetry showed an additional anodic peak beyond Mn2 II,III/III,III oxidation which was significantly lower than in neat acetonitrile. Assuming that this peak is due to oxidation to Mn2 III,IV, this suggests that water is essential for the formation of the Mn2 III,IV oxidation state. Compound 2 is a structural mimic of the water oxidizing complex, in that it links a Mn complex via a tyrosine to a highly oxidizing photosensitizer. Complex 2 also mimics mechanistic aspects of Photosystem II, in that the electron transfer to the photosensitizer is fast and results in several electron extractions from the Mn moiety.

KW - Artificial photosynthesis

KW - Bioinorganic chemistry

KW - Electrochemistry

KW - EPR spectroscopy

KW - Manganese

UR - http://www.scopus.com/inward/record.url?scp=0011145488&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0011145488&partnerID=8YFLogxK

U2 - 10.1016/S0162-0134(02)00394-X

DO - 10.1016/S0162-0134(02)00394-X

M3 - Article

C2 - 12121773

AN - SCOPUS:0011145488

VL - 91

SP - 159

EP - 172

JO - Journal of Inorganic Biochemistry

JF - Journal of Inorganic Biochemistry

SN - 0162-0134

IS - 1

ER -