Anion-Dependent Assembly of Heterometallic 3d-4f Clusters Based on a Lacunary Polyoxometalate

A series of heterometallic 3d-4f clusters, formulated as Na-17[Ln(3)(H2O)(5)Ni-II(H2O)(3)(Sb4O4)(SbW9O33)(3)((NiW6O24)-W-II)(WO2)(3)(CH3COO)]center dot (H2O)(65) [abbreviated as Ln(3)Ni(2), where Ln = La3+ (1), Pr3+ (2), and Nd3+ (3)], K5Na11[Ln(3)(H2O)(3)Ni-3(II)(H2O)(6)(SbW9O33)(3)(WO4)(CO3)]center dot(H2O)(40) [abbreviated as Ln(3)Ni(3), where Ln = La3+ (4), Pr3+ (5), and Nd3+ (6)], and K3Na27[Ln(3)Ni(9)(II)(mu(3)-OH)(9)(SbW9O33)(2)(PW9O34)(3)(CH3COO)]center dot(H2O)(80) [abbreviated as Ln(3)Ni(9), where Ln = Dy3+ (7) and Er3+ (8)], were obtained through the reaction of the lacunary {SbW9O33} precursor with Ln(NO3)(3)center dot 6H(2)O and NiCl2 center dot 6H(2)O in a NaAc/HAc buffer in the presence of different anions. Single-crystal X-ray structure analysis revealed that compounds 1-3 possessed tetrameric architectures featuring three Keggin-type {SbW9O33} and one Anderson-type {(NiW6O24)-W-II} building blocks encapsulating one {Sb4O4} cluster, three WO2 units, three Ln(3+) metal ions, and two Ni2+ metal ions. Compounds 4-6 displayed cyclic trimeric aggregates of three {SbW9O33} units enveloping one CO32--tertiplated trinuclear [Ln(3)(CO3)](7+) and one WO42--templated [Ni-3(II)(WO4)](+). unit. Compounds 7 and 8 exhibited unique pentameric architectures that featured three 3d-4f cubane clusters of {LnNi(3)(mu(3)-OH)(3)} capped by two {SbW9O33} and three {PW9O34} building blocks. Interestingly, the structural regulation of the heterometallic 3d-4f clusters in the polyoxometalate systems with trimers, tetramers, and pentamers was realized by introducing different anions.