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Updated: Jun 23, 2026
10:51
The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Photochromic ruthenium sulfoxide complexes: evidence for isomerization through a conical intersection
Beth Anne McClure1, Nicholas V Mockus, Dennis P Butcher
1Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, USA.
Inorganic Chemistry
|May 14, 2009
Summary
Ruthenium complexes with 2-methylthiobenzoate and 2-methylsulfinylbenzoate ligands undergo light- or electrochemically induced S-to-O isomerization. This reversible process, observed in [Ru(bpy)2(OSO)]+, shows a large photoisomerization quantum yield and rapid excited state isomerization.
Area of Science:
- Organometallic Chemistry
- Photochemistry
- Coordination Chemistry
Background:
- Ruthenium polypyridyl complexes are vital in photochemistry and catalysis.
- Sulfoxide ligands offer unique coordination modes (S- vs. O-bonding).
- Understanding ligand isomerization is key to controlling complex reactivity.
Purpose of the Study:
- To investigate the electrochemical and photochemical behavior of [Ru(bpy)2(OS)]+ and [Ru(bpy)2(OSO)]+ complexes.
- To elucidate the mechanism of S- to O-bonded sulfoxide isomerization in ruthenium complexes.
- To determine the kinetics and thermodynamics of this isomerization process.
Main Methods:
- Synthesis and characterization of ruthenium-sulfoxide complexes.
- Electrochemical studies using cyclic voltammetry.
- Photochemical investigations including UV-Vis spectroscopy and quantum yield measurements.
- Kinetic analysis of isomerization using time-resolved spectroscopy.
- Density Functional Theory (DFT) calculations.
Main Results:
- Photo- and electrochemical oxidation trigger S- to O-isomerization in [Ru(bpy)2(OSO)]+.
- Isomerization leads to changes in metal-to-ligand charge transfer (MLCT) bands.
- The isomerization is reversible in solution at room temperature.
- Kinetic analysis reveals biexponential decay, indicating distinct isomerization pathways.
- Photoisomerization quantum yield is high (0.45 in methanol).
- DFT calculations support the observed spectroscopy and bonding.
Conclusions:
- The study demonstrates a facile and reversible S- to O-sulfoxide isomerization in ruthenium complexes.
- Isomerization occurs nonadiabatically from an excited state.
- Electron-transfer-triggered isomerization is a viable pathway.
- Ruthenium polypyridyl sulfoxide complexes offer tunable photochemical properties.
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