Record High-Nuclearity Polyoxoniobates: Discrete Nanoclusters {Nb }, {Nb }, and {Nb }, and Extended Frameworks Based on {Cu Nb } and {Cu Nb }.

A series containing the highest nuclearity polyoxoniobate (PONb) nanoclusters, ranging from dimers to tetramers, has been obtained. They include one 114-nuclear {Li ⊂Nb O }, one 81-nuclear {Li K⊂Nb O }, and one 52-nuclear {H Nb O }. The Nb nuclearity of these PONbs is remarkably larger than those of all known high-nuclearity PONbs (≤32). Furthermore, the introduction of 3d Cu ions can lead to the generation of extended inorganic-organic hybrid frameworks built from novel, high-nuclearity, nanoscale heterometallic PONb building blocks {H Cu Nb O } or {H Cu (en)Nb O }. 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.