Efficient catalysis of Knoevenagel condensation by 1D copper-containing heteropolyoxoniobate at room temperature

Abstract

A 1D copper-containing organic–inorganic hybrid heteropolyoxoniobate, H₃[K(H₂O)₆][K₂(H₂O)₁₀]₂[Cu(en)₂(H₂O)₂][Cu(en)₂(Nb₆O₁₉Cu(en))₂]·24H₂O (HPONb 1), has been synthesized to heterogeneously catalyze Knoevenagel condensation at room temperature with high yields and cycling stability. The catalyst presents the best catalytic activity for Knoevenagel condensation among the polyoxometalates (POMs) reported to date.