{Nb₂₈₈O₇₆₈(OH)₄₈(CO₃)₁₂}: A Macromolecular Polyoxometalate with Close to 300 Niobium Atoms

Abstract

A protein-sized (ca. 4.2×4.2×3.6 nm ) non-biologically derived molecule {Nb O (OH) (CO ) } (Nb ) containing up to 288 niobium atoms has been obtained, which is by far the largest and the highest nuclearity polyoxoniobate (PONb). Particularly, in terms of metal nuclearity number, Nb is the second largest cluster so far reported in classic polyoxometalate chemistry (V, Mo, W, Nb, and Ta). Nb can be described as a giant windmill-like cluster aggregate of six nanoscale high-nuclearity PONb units {Nb O (OH) (CO ) } (Nb ) joined together by six additional Nb ions. Interestingly, the 47-nuclearity Nb units generated in situ can be isolated and bridged by copper complexes to form an inorganic-organic hybrid three-dimensional PONb framework, which exhibits effective catalytic activity for hydrolyzing nerve agent simulant of dimethyl methylphosphonate. The unique Nb cluster also provides a new type of topology to very limited family of Nb-O clusters.

Polyoxometalates: Tailoring metal oxides in molecular dimension toward energy applications

“…Cobalt‐containing and chromium‐containing polyoxoniobates such as Na 6 K 12 [H 2 Co 8 O 4 (Nb 6 O 19 ) 4 ]·39H 2 O are produced to demonstrate their novel electronic and magnetic properties . Novel polyoxoniobate structures have been constructed; for example, polyoxoniobates with a large number of niobium atoms based on Nb 114 , Nb 81 , Nb 52 , Cu 3 Nb 78 , and Cu 4 Nb 78 have been synthesized, while an even larger‐size polyoxoniobate Nb 288 O 768 (OH) 48 (CO 3 ) 12 has been successfully produced . Their electronic and optical properties deserve more careful scrutiny for energy applications.…”

Strategic Capture of the {Nb7} Polyoxometalate

“…The Lindqvist hexaniobate is the predominant species in aqueous solution above pH 12, and has been used as a precursor for the synthesis of larger compounds by reducing pH, applying hydrothermal conditions, and adding heteroatoms. Several higher nuclearity PONb‐clusters were isolated in the last decade by this approach including {Nb 24 }, {Nb 32 }, {Nb 52 }, {Nb 81 }, {Nb 114 }, and {Nb 288 } . Most of these are built of either Keggin‐derivatives, first isolated in 2002, or from a modified Lindqvist ion; the heptaniobate {Nb 7 } (Figure ).…”

Soluble Hetero‐Polyoxovanadates and Their Solution Chemistry Analyzed by Electrospray Ionization Mass Spectrometry

“…The usage of prebuild synthons in the preparation of polyoxometalates has gained increasing interest because high nuclearity clusters have already demonstrated an immense range of promising properties, as mentioned above. In this regard, the assembly of POM substructures to form larger and highly ordered architectures is especially interesting, but also challenging …”

“…The usage of prebuild synthons in the preparation of polyoxometalates has gained increasing interestbecause high nuclearity clusters have already demonstrated an immenser ange of promising properties, as mentioned above.I nt his regard, the assemblyo fP OM substructures to form larger and highly ordered architectures is especially interesting, but also challenging. [10,41] Luban and co-workersp resented an intriguing example of a well-ordered assembly from at otal of 13 substructures. [42] They combined as upramolecular templating effect and ak inetic competition approacht os electively generate the complex {Mn 40 W 224 }p olyanionic architecture 1,w hich was characterized by single-crystal structure determination (Figure 5a).…”