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Water Oxidation by Ruthenium Complexes Incorporating Multifunctional Bipyridyl Diphosphonate Ligands
Author(s) -
Xie Yan,
Shaffer David W.,
LewandowskaAndralojc Anna,
Szalda David J.,
Concepcion Javier J.
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201601943
Subject(s) - ruthenium , deprotonation , phosphonate , chemistry , catalysis , electrochemistry , redox , yield (engineering) , photochemistry , combinatorial chemistry , inorganic chemistry , materials science , ion , organic chemistry , electrode , metallurgy
We describe herein the synthesis and characterization of ruthenium complexes with multifunctional bipyridyl diphosphonate ligands as well as initial water oxidation studies. In these complexes, the phosphonate groups provide redox‐potential leveling through charge compensation and σ donation to allow facile access to high oxidation states. These complexes display unique pH‐dependent electrochemistry associated with deprotonation of the phosphonic acid groups. The position of these groups allows them to shuttle protons in and out of the catalytic site and reduce activation barriers. A mechanism for water oxidation by these catalysts is proposed on the basis of experimental results and DFT calculations. The unprecedented attack of water at a neutral six‐coordinate [Ru IV ] center to yield an anionic seven‐coordinate [Ru IV −OH] − intermediate is one of the key steps of a single‐site mechanism in which all species are anionic or neutral. These complexes are among the fastest single‐site catalysts reported to date.