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

Abstract

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.

Strategic Capture of the {Nb7} Polyoxometalate

“…The last compound ({Nb 14 } Figure ) crystallizes as colorless square plates (orthorhombic Pccn , see Supporting Information) from the {Nb 10 }–Li–U 1 aqueous mixture following slow evaporation of the solution. The {Nb 14 } structure provides a unique prospective of the {Nb 7 } fragment; this is its first isolation as a species different from {Nb 24 } and without a heterometal . The {Nb 7 } unit (Figure ) is as described above.…”

“…The {Nb 14 }s tructure provides au nique prospective of the {Nb 7 }f ragment;t his is itsf irst isolation as a species different from {Nb 24 }a nd withoutah eterometal. [12,13] The {Nb 7 }u nit (Figure 1) is as described above.O ft he three "terminal"s ites of the appendage-Nb (Nb7 in the cif), two are disordered oxo/peroxide, and the third bridges to the second {Nb 7 }u nit. The Nb = O yl -Nb bond distance is % 2.0 ,a nd the bond angle that bridges the two {Nb 7 }u nits is slightly bent at 1638.P rior,a na nalogueo f{ Nb 14 }i nw hich Pt with terminal cis-OH ligandslocated at the Nb7 site was reported.…”

“…The Lindqvist hexaniobate is the predominant species in aqueous solution above pH 12, and has been used as ap recursor for the synthesis of larger compoundsb yr educing pH, applying hydrothermal conditions, and adding heteroatoms. Severalh ighern uclearity PONb-clusters were isolated in the last decade by this approachi ncluding {Nb 24 }, [12] {Nb 32 }, [12b] {Nb 52 }, [13] {Nb 81 }, [13] {Nb 114 }, [13] and{ Nb 288…”

All‐Inorganic Ionic Porous Material Based on Giant Spherical Polyoxometalates Containing Core‐Shell K6@K36‐Water Cage

“…[10,11] During the past two decades,amethod of using lacunary POM precursors as templates has been developed for the formation of various high-nuclearity metal-oxygen clusters, such as Mn 19 -, [ Despite the significant successes,m ost incoporated high-nuclearity metal clusters are those based on bivalent transition metals or trivalent rare earth metals.V ery few nanoscale high-nuclearity clusters based on monovalent alkali metal (AM) ions have been known in POM chemistry.A ctually,d ue to isotropic Coulombic interactions in al ong range,A Ms favor the formation of infinite extended structures (e.g.,chains and layers), [12] and so thus the nanoscale AM clusters are also rare even in whole cluster chemistry.G enerally,t he construction of high-nuclearity AM clusters formed by ionic bonds is much more difficult than that of metal oxygen clusters formed by coordination or covalent bonds. [10,11] During the past two decades,amethod of using lacunary POM precursors as templates has been developed for the formation of various high-nuclearity metal-oxygen clusters, such as Mn 19 -, [ Despite the significant successes,m ost incoporated high-nuclearity metal clusters are those based on bivalent transition metals or trivalent rare earth metals.V ery few nanoscale high-nuclearity clusters based on monovalent alkali metal (AM) ions have been known in POM chemistry.A ctually,d ue to isotropic Coulombic interactions in al ong range,A Ms favor the formation of infinite extended structures (e.g.,chains and layers), [12] and so thus the nanoscale AM clusters are also rare even in whole cluster chemistry.G enerally,t he construction of high-nuclearity AM clusters formed by ionic bonds is much more difficult than that of metal oxygen clusters formed by coordination or covalent bonds.…”

“…On the other hand, the incorporation of high-nuclearity metal-oxygen clusters into POMs has been attracting great interest in POM chemistry owing to their unique structural features and appealing physicochemical properties. [10,11] During the past two decades,amethod of using lacunary POM precursors as templates has been developed for the formation of various high-nuclearity metal-oxygen clusters, such as Mn 19 -, [10a] Fe 28 -, [10b] Co 16 -, [10c] Ni 25 -, [10d] Cu 20 -, [10e] Zr 24 -, [10f] Ag 18 -, [10g] and Ln 26 -containing POMs. [10h] Despite the significant successes,m ost incoporated high-nuclearity metal clusters are those based on bivalent transition metals or trivalent rare earth metals.V ery few nanoscale high-nuclearity clusters based on monovalent alkali metal (AM) ions have been known in POM chemistry.A ctually,d ue to isotropic Coulombic interactions in al ong range,A Ms favor the formation of infinite extended structures (e.g.,chains and layers), [12] and so thus the nanoscale AM clusters are also rare even in whole cluster chemistry.G enerally,t he construction of high-nuclearity AM clusters formed by ionic bonds is much more difficult than that of metal oxygen clusters formed by coordination or covalent bonds.…”