Assembly of Tungsten‐Oxide‐Based Pentagonal Motifs in Solution Leads to Nanoscale {W 48 }, {W 56 }, and {W 92 } Polyoxometalate Clusters

We report an approach to synthesize molecular tungsten‐oxide‐based pentagonal building blocks, in a new {W 21 O 72 } unit, and show how this leads to a family of gigantic molecular architectures including [H 12 W 48 O 164 ] 28− {W 48 }, [H 20 W 56 O 190 ] 24− {W 56 }, and [H 12 W 92 O 311 ] 58− {W 92 }. The {W 48 } and {W 56 } clusters are both dimeric species incorporating two {W 21 } units and the {W 56 } species is the first example of a molecular metal oxide cluster containing a chiral “double‐stranded” motif which is stable in solution as confirmed by mass spectrometry. The {W 92 } anion having four {W 21 } units is one of the largest transition metal substituted isopolyoxotungstates known.