TY - JOUR
T1 - Towards an artificial model for Photosystem II
T2 - A manganese(II,II) dimer covalently linked to ruthenium(II) tris-bipyridine via a tyrosine derivative
AU - Sun, Licheng
AU - Raymond, Mary Katherine
AU - Magnuson, Ann
AU - Legourriérec, Denis
AU - Tamm, Markus
AU - Abrahamsson, Malin
AU - Huang Kenéz, Ping
AU - Mårtensson, Jerker
AU - Stenhagen, Gunnar
AU - Hammarström, Leif
AU - Styring, Stenbjörn
AU - Åkermark, Björn
N1 - Funding Information:
This work was supported by grants from the Knut and Alice Wallenberg Foundation, the Swedish Natural Science Research Council, the Swedish Research Council for Engineering Sciences, the European TMR Program (TMR Network CT96-0031), and the Nordic Energy Research Program. We thank Dr Peter Brandt for molecular modeling, and Drs Mark Burkitt and Yves Frapart for valuable discussions.
PY - 2000/1/15
Y1 - 2000/1/15
N2 - In order to model the individual electron transfer steps from the manganese cluster to the photooxidized sensitizer P680+ in Photosystem II (PS II) in green plants, the supramolecular complex 4 has been synthesized. In this complex, a ruthenium(II) tris-bipyridine type photosensitizer has been linked to a manganese(II) dimer via a substituted L-tyrosine, which bridges the manganese ions. The trinuclear complex 4 was characterized by electron paramagnetic resonance (EPR) and electrospray ionization mass spectrometry (ESI-MS). The excited state lifetime of the the ruthenium tris-bipyridine moiety in 4 was found to be about 110 ns in acetonitrile. Using flash photolysis in the presence of an electron acceptor (methylviologen), it was demonstrated that in the supramolecular complex 4 an electron was transferred from the excited state of the ruthenium tris-bipyridine moiety to methylviologen, forming a methylviologen radical and a ruthenium(III) tris-bipyridine moiety. Next, the Ru(III) species retrieved the electron from the manganese(II/II) dimer in an intramolecular electron transfer reaction with a rate constant k(ET)>1.0x107 s-1, generating a manganese(II/III) oxidation state and regenerating the ruthenium(II) photosensitizer. This is the first example of intramolecular electron transfer in a supramolecular complex, in which a manganese dimer is covalently linked to a photosensitizer via a tyrosine unit, in a process which mimics the electron transfer on the donor side of PS II. Copyright (C) 1999 Elsevier Science Inc.
AB - In order to model the individual electron transfer steps from the manganese cluster to the photooxidized sensitizer P680+ in Photosystem II (PS II) in green plants, the supramolecular complex 4 has been synthesized. In this complex, a ruthenium(II) tris-bipyridine type photosensitizer has been linked to a manganese(II) dimer via a substituted L-tyrosine, which bridges the manganese ions. The trinuclear complex 4 was characterized by electron paramagnetic resonance (EPR) and electrospray ionization mass spectrometry (ESI-MS). The excited state lifetime of the the ruthenium tris-bipyridine moiety in 4 was found to be about 110 ns in acetonitrile. Using flash photolysis in the presence of an electron acceptor (methylviologen), it was demonstrated that in the supramolecular complex 4 an electron was transferred from the excited state of the ruthenium tris-bipyridine moiety to methylviologen, forming a methylviologen radical and a ruthenium(III) tris-bipyridine moiety. Next, the Ru(III) species retrieved the electron from the manganese(II/II) dimer in an intramolecular electron transfer reaction with a rate constant k(ET)>1.0x107 s-1, generating a manganese(II/III) oxidation state and regenerating the ruthenium(II) photosensitizer. This is the first example of intramolecular electron transfer in a supramolecular complex, in which a manganese dimer is covalently linked to a photosensitizer via a tyrosine unit, in a process which mimics the electron transfer on the donor side of PS II. Copyright (C) 1999 Elsevier Science Inc.
KW - Artificial photosynthesis
KW - Electron transfer
KW - Manganese dimer complexes
KW - Photosystem II
KW - Ruthenium complexes
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U2 - 10.1016/S0162-0134(99)00200-7
DO - 10.1016/S0162-0134(99)00200-7
M3 - Article
C2 - 10714701
AN - SCOPUS:0034651173
VL - 78
SP - 15
EP - 22
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
SN - 0162-0134
IS - 1
ER -