A Functional Model for O-O Bond Formation by the O2-Evolving Complex in Photosystem II
Julian Limburg,
1
John S. Vrettos,
1
Louise
M. Liable-Sands,
2
Arnold L. Rheingold,
2
Robert H. Crabtree,
1*
Gary W. Brudvig
1*
The formation of molecular oxygen from water in photosynthesis is
catalyzed by photosystem II at an active site containing four manganese
ions that are arranged in di-µ-oxo dimanganese units (where µ is a
bridging mode). The complex
[H2O(terpy)Mn(O)2Mn(terpy)OH2](NO3)3 (terpy is 2,2':6',2"-terpyridine), which was synthesized and
structurally characterized, contains a di-µ-oxo manganese dimer and
catalyzes the conversion of sodium hypochlorite to molecular oxygen.
Oxygen-18 isotope labeling showed that water is the source of the
oxygen atoms in the molecular oxygen evolved, and so this system is a functional model for photosynthetic water oxidation.
1 Department of Chemistry, Yale University,
Post Office Box 208107, New Haven, CT 06520-8107, USA.
2 Crystallography Laboratory, Department of
Chemistry, University of Delaware, Newark, DE 19716, USA.
*
To whom correspondence should be addressed. E-mail:
robert.crabtree{at}yale.edu; gary.brudvig{at}yale.edu
