Assembly of sandwich-type ruthenium-containing polyoxometalates for efficient construction of C–C bonds

Abstract

A novel inorganic sandwich-type ruthenium-containing polyoxometalate, K₈Na₃H₉[Ru₄O₄{W₉O₃₃}₂]·30H₂O (Ru₄W₁₈), featuring a central parallelogram-shaped tetranuclear ruthenium oxo cluster {Ru₄} that bridges two trivacant [W₉O₃₃]¹²⁻ units, was synthesised in this study. The Ru₄W₁₈ as a heterogeneous catalyst achieved a yield of 95.8% in the Knoevenagel condensation reaction, validating synergistic catalysis by ruthenium species and polyoxometalates.