An oxalate-assisted lanthanide (Ln) incorporation strategy is first demonstrated for creating rare high-nuclearity Lncontaining polyoxoniobates (PONbs). With the strategy, a series of high-nuclearity Ln-containing PONbs of 50-nuclearity Dy 2 Nb 48 , 103-nuclearity Dy 7 Nb 96 , 200-nuclearity Dy 10 Nb 190 , and 206nuclearity Dy 14 Nb 192 have been made, showing an increasingly large structure evolution from Dy 2 Nb 48 monomer to Dy 7 Nb 96 dimer and to distinct Dy 10 Nb 190 and Dy 14 Nb 192 tetramers. Among them, Dy 14 Nb 192 presents the largest heterometallic PONb and also the PONb with the greatest number of Ln ions reported thus far. Interestingly, both giant Dy 14 Nb 192 and Dy 10 Nb 190 molecules can further undergo single-crystal to single-crystal intermolecular aggregations, forming infinite {Dy 14 Nb 192 } ∞ and {Dy 10 Nb 190 } ∞ chains, respectively. The former structural transformation shows a reversible humidity-dependent aggregation−disaggregation process accompanied by a proton conductivity response, while the latter structural transformation is irreversible. These new species largely enrich the very limited members of Ln-containing PONb family and offer rare examples for studying structural transformations between giant molecular aggregates and infinitely extended structures at the atomic level.

Two new extended polyoxometalate (POM) architectures based on lanthanide-incorporated polyoxoniobate (Ln-incorporated PONb) cages, namely, H4[CuII(en)2]4{K4(H2O)2­[CuII(en)2]5[CuII 5­​(trz)2(en)4(OH)2]­[Dy2CuII 2­(en)2(CO3)3­(H2O)2(OH)3]­[Dy­(H2O)4]­[Dy­Nb23O68­(H2O)4]2}·60H2O (1, en = ethylenediamine) and H20[CuII(en)2]4­{[CuII(en)2]4­[Dy2(C2O4)­(H2O)4]2­[(Nb32(OH)4­(H2O)3­O89]2}·54H2O (2), have been successfully synthesized and structurally characterized, demonstrating a feasible strategy to develop functional POM materials. In addition, the proton conductivity and magnetic behaviors of both 1 and 2 were studied.

A tetratellurium-substituted heteropolyoxoniobate with the formula K2H­[Cu­(phen)­(H2O)]4[Cu­(phen)]2[(LiNb8Te4O40)]·34H2O (1; phen = 1,10-phenanthroline) was hydrothermally prepared and structurally characterized. The compound represents the first hexavalent tellurium-substituted Keggin-type polyoxometalate (POM) so far. What is more, the POM cluster in 1 can elaborately self-assemble into a stable supramolecular framework with an ion conduction property through unique intermolecular π–π stacking.

A rare sandwich-type heteropolyoxoniobate cluster [Eu(H2O)3Te6Nb18O64(OH)4]15- {EuTe6Nb18}, has been isolated by simultaneously incorporating lanthanide cation and tellurite anions into the polyoxoniobate. {EuTe6Nb18} cluster represents the first examples of lanthanide-incorporated telluroniobate...

An oxalate-assisted strategy was first developed for creating new polyoxotantalates (POTas). With the strategy, two brand-new POTa supramolecular frameworks based on uncommon dimeric POTa secondary building units (SBUs) were constructed...