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, [SiW11O39RuIII(Py)]5−

Abstract 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.