Record High-Nuclearity Polyoxoniobates: Discrete Nanoclusters {Nb114 }, {Nb81 }, and {Nb52 }, and Extended Frameworks Based on {Cu3 Nb78 } and {Cu4 Nb78 }.

A series containing the highest nuclearity polyoxoniobate (PONb) nanoclusters, ranging from dimers to tetramers, has been obtained. They include one 114-nuclear {Li8 ⊂Nb114 O316 }, one 81-nuclear {Li3 K⊂Nb81 O225 }, and one 52-nuclear {H4 Nb52 O150 }. The Nb nuclearity of these PONbs is remarkably larger than those of all known high-nuclearity PONbs (≤32). Furthermore, the introduction of 3d Cu2+ ions can lead to the generation of extended inorganic-organic hybrid frameworks built from novel, high-nuclearity, nanoscale heterometallic PONb building blocks {H3 Cu3 Nb78 O222 } or {H3 Cu4 (en)Nb78 O222 }. These building blocks also contain the largest number of Nb centers of any heterometallic PONbs reported to date. The synthesis of new-type PONbs has long been a challenging subject in PONb chemistry.