TY - JOUR
T1 - The first spectroscopic model for the S1 state multiline signal of the OEC
AU - Hsieh, Wen Yuan
AU - Campbell, Kristy A.
AU - Gregor, Wolfgang
AU - Britt, R. David
AU - Yoder, Derek W.
AU - Penner-Hahn, James E.
AU - Pecoraro, Vincent L.
PY - 2004/4/12
Y1 - 2004/4/12
N2 - The parallel-mode electron paramagnetic resonance (EPR) spectrum of the S1 state of the oxygen-evolving complex (OEC) shows a multiline signal centered around g=12, indicating an integer spin system. The series of [Mn2(2-OHsalpn)2] complexes were structurally characterized in four oxidation levels (MnII2, Mn IIMnIII, MnIII2, and Mn IIIMnIV). By using bulk electrolysis, the [Mn IIIMnIV(2-OHsalpn)2(OH)] is oxidized to a species that contains MnIV oxidation state as detected by X-ray absorption near edge spectroscopy (XANES) and that can be formulated as Mn IV4 tetramer. The parallel-mode EPR spectrum of this multinuclear MnIV4 complex shows 18 well-resolved hyperfine lines center around g=11 with an average hyperfine splitting of 36 G. This EPR spectrum is very similar to that found in the S1 state of the OEC. This is the first synthetic manganese model complex that shows an S1-like multiline spectrum in parallel-mode EPR.
AB - The parallel-mode electron paramagnetic resonance (EPR) spectrum of the S1 state of the oxygen-evolving complex (OEC) shows a multiline signal centered around g=12, indicating an integer spin system. The series of [Mn2(2-OHsalpn)2] complexes were structurally characterized in four oxidation levels (MnII2, Mn IIMnIII, MnIII2, and Mn IIIMnIV). By using bulk electrolysis, the [Mn IIIMnIV(2-OHsalpn)2(OH)] is oxidized to a species that contains MnIV oxidation state as detected by X-ray absorption near edge spectroscopy (XANES) and that can be formulated as Mn IV4 tetramer. The parallel-mode EPR spectrum of this multinuclear MnIV4 complex shows 18 well-resolved hyperfine lines center around g=11 with an average hyperfine splitting of 36 G. This EPR spectrum is very similar to that found in the S1 state of the OEC. This is the first synthetic manganese model complex that shows an S1-like multiline spectrum in parallel-mode EPR.
KW - Electron paramagnetic resonance (EPR)
KW - Manganese complex
KW - S state
KW - X-ray absorption near edge spectroscopy (XANES)
UR - http://www.scopus.com/inward/record.url?scp=1942536561&partnerID=8YFLogxK
U2 - 10.1016/j.bbabio.2003.12.001
DO - 10.1016/j.bbabio.2003.12.001
M3 - Review article
C2 - 15100027
AN - SCOPUS:1942536561
SN - 0005-2728
VL - 1655
SP - 149
EP - 157
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
IS - 1-3
ER -