A tetrameric polyoxometalate with two orderly and dense double-layered {Ni12W8/3} cluster centers

Abstract

A germanotungstate aggregate, [H₂N(CH₃)₂]₈Na₂H₁₈[{Ni₁₂W_8/3O₁₄–(OH)₃(H₂O)₃}{BO(OH)₂}{B₂O₃(OH)₂}(B-α-GeW₉O₃₄)₂]₂·14H₂O (1), with the highest nuclearity Ni cluster core among known poly(polyoxometalate) tetramers has been developed, which contains two unprecedented orderly and dense double-layered central Ni–W–O cluster cores that are further decorated by different oxo-B groups. Moreover, 1 is an efficient heterogeneous catalyst for accelerating the Knoevenagel reactions of various aldehydes with malononitrile.