US EPA

1038308 

Journal Article 

Stabilization of high-valence ruthenium with silicotungstate ligands: Preparation, structural characterization, and redox studies of ruthenium(III)-substituted α-keggin-type silicotungstates with pyridine ligands, [SIW(11) o(39) RU(III) (PY)](5-) 

Sadakane, M; Moroi, S; Iimuro, Y; Izarova, N; Kortz, U; Hayakawa, S; Kato, K; Ogo, S; Ide, Y; Ueda, W; Sano, T 

2012 

Yes 

Chemistry - An Asian Journal
ISSN: 1861-4728
EISSN: 1861-471X 

7 

6 

1331-1339 

English 

22311603 

10.1002/asia.201100853 

WOS:000304440600022 

Ruthenium(III)-substituted α-Keggin-type silicotungstates with pyridine-based ligands, [SiW(11) O(39) Ru(III) (Py)](5-) , (Py: pyridine (1), 4-pyridine-carboxylic acid (2), 4,4'-bipyridine (3), 4-pyridine-acetamide (4), and 4-pyridine-methanol (5)) were prepared by reacting [SiW(11) O(39) Ru(III) (H(2) O)](5-) with the pyridine derivatives in water at 80 °C and then isolated as their hydrated cesium salts. These compounds were characterized using cyclic voltammetry (CV), UV/Vis, IR, and (1) H NMR spectroscopy, elemental analysis, titration, and X-ray absorption near-edge structure (XANES) analysis (Ru K-edge and L(3) -edge). Single-crystal X-ray analysis of compounds 2, 3, and 4 revealed that Ru(III) was incorporated in the α-Keggin framework and was coordinated by pyridine derivatives through a RuN bond. In the solid state, compounds 2 and 3 formed a dimer through ππ interaction of the pyridine moieties, whereas they existed as monomers in solution. CV indicated that the incorporated Ru(III) -Py was reversibly oxidized into the Ru(IV) -Py derivative and reduced into the Ru(II) -Py derivative. 

pi interactions; polyanions; redox chemistry; ruthenium; substituent effects