Record High‐Nuclearity Polyoxoniobates: Discrete Nanoclusters {Nb114}, {Nb81}, and {Nb52}, and Extended Frameworks Based on {Cu3Nb78} and {Cu4Nb78}

A series containing the highest nuclearity polyoxoniobate (PONb) nanoclusters, ranging from dimers to tetramers, has been obtained. They include one 114‐nuclear {Li8⊂Nb114O316}, one 81‐nuclear {Li3K⊂Nb81O225}, and one 52‐nuclear {H4Nb52O150}. 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 {H3Cu3Nb78O222} or {H3Cu4(en)Nb78O222}. 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. Sehr große PONbs, von einer {Nb52}‐ über eine {Nb81}‐ zu einer {Nb114}‐Spezies, wurden hergestellt. Durch Einführung von 3d‐Ionen (Cu2+) werden ausgedehnte organisch‐anorganische PONb‐Hybridgerüste aufgebaut, die riesige {Cu3Nb78}‐ und {Cu4Nb78}‐Heterometallnanocluster enthalten.