An {As₄Cu₄[Cu(H₂O)]₁₂} Cluster Incorporated within Four [Nb₇O₂₂]⁹⁻ Units

Abstract

A gigantic 16-copper-containing 28-niobate cluster, Na K H {As Cu [Cu(H O)] Nb O }⋅37.5 H O (1), has been prepared by a one-pot reaction, which is the first example of arsenic copper clusters containing polyoxoniobate, and the first tetrahedral arrangement of both the Cu cluster and the [Nb O ] subunits.

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

“…A very recent example for an impressive supramolecular architecture containing several POMs was presented by Wang and co‐workers in 2017. They demonstrated the formation of the host‐guest complex {As 4 Cu 4 [Cu(H 2 O)] 12 }@{Nb 7 O 22 } 4 4 (Figure a) . A one‐pot reaction starting from the Lindqvist‐type {Nb 6 O 19 } cluster, as well as homonuclear copper and arsenic precursors in basic aqueous medium led to the stepwise self‐assembly of the complex as evidenced by single‐crystal X‐ray structure analysis.…”

“…Reprinted and adapted with permission from ref. (Copyright 2017 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim).…”

“…The synthesis of new POMs often occurs by template‐induced post‐functionalization or rearrangement processes of a substrate cluster into another one. To rationalize and explore these processes, ESI‐MS is commonly applied …”

Capturing the Heptaniobate {Nb7O22}9– Anion by Covalent Bond Formation: Synthesis, Crystal Structure, and Selected Properties of {[Fe(cyclam)]3Nb7O22}· ≈ 19 H2O

“…(a) The dimeric {Nb 14 O 40 } cluster; (b) the trimeric {Nb 24 O 72 } cluster with a K + cation in the middle of the ring . (c) the {Nb 32 O 96 } cluster with an empty ring; (d) the {Nb 28 O 109 } unit with a network of copper, arsenic and oxygen ions joining four heptaniobate units; (e) the dimer of the {Nb 24 O 72 } cluster connected by europium ions leading to a {Nb 48 O 138 } cluster; (f) eight {Nb 7 O 22 } moieties linked by Cu 2+ ions forming K 12 Na[H 23 NbO 8 Cu 24 (Nb 7 O 22 ) 8 ] · 81 H 2 O . Color code: Niob centered polyhedra in lime and the additional [NbO 6 ] octahedron of the {Nb 7 O 22 } cluster highlighted in orange, O in red, Cu in blue, Eu in pink, K in dark green and As in violet.…”

“…A different structural motif containing the {Nb 7 O 22 } cluster is found in the compounds Na 14 K 7 H 5 {As 4 Cu 4 [Cu(H 2 O)] 12 Nb 28 O 109 } · 37.5H 2 O or Li 14 [(Nb 7 O 22 H 2 ) 4 (UO 2 ) 7 (H 2 O) 6 ] · 65 H 2 O, where four {Nb 7 O 22 } units are linked in a tetrahedral‐like manner by Cu, As and O atoms or U and O atoms (Figure d). Dimerization of two {Nb 24 O 72 } moieties leads to formation of the {Nb 48 O 138 } cluster, which was observed in (CN 3 H 6 ) 7 K 3 H 17 {Eu 3 (H 2 O) 9 Nb 48 O 138 (H 2 O) 6 } · 40 H 2 O (Figure e) and Li 15 (TMA) 2 [(UO 2 )(H 2 O)] 3 [Nb 46 (UO 2 ) 2 O 136 H 8 (H 2 O) 4 ] · 41 H 2 O .…”