Assembly of Pure Silver‐Tungsten‐Oxide Frameworks from Nanostructured Solution Processable Clusters and Their Evolution into Materials with a Metallic Component

described as an array of MO x polyhedral units (M = W, Mo, V, Nb or Ta; x = 4–7) linked via edge, corner and occasionally face sharing modes and are assembled from the hydrolytic aggregation of mononuclear oxometalates. [ 2 , 3 ] With an unrivalled range of tuneable properties, POMs exhibit a diverse range of applications in many areas of chemistry including catalysis, [ 4 , 5 ] medicine, [ 6 ] magnetism, [ 7–9 ] materials [ 10 , 11 ] and surface studies. [ 12 ] Despite the vast potential of anionic POM clusters as precursors to form novel materials and their application in materials science, the ability to exploit the molecular structure of the clusters in the assembly of framework materials, and to control their reactivity, has been greatly limited. This is because of the seemingly infi nite numbers of non specifi c ionic assemblies that can be assembled by the combination of the anionic POM clusters with the charge balancing cations. Any new breakthrough in this area requires the ability to exploit the bottom up assembly of nanostructured clusters in solution, with a well defi ned linking strategy that gives rise to the overall material. Taking all of these factors into account, it is clear that the traditional routes to POM formation involved an element of serendipity, due to a poor understanding of reaction mechanisms. Given these issues it is not surprising that solution processable POM precursors, although potentially transformative, have not been routinely used in the assembly of novel ‘pure’ inorganic solid-state frameworks. In an effort to combat these complex issues, we recently developed a synthetic strategy to design novel clusters, by cation exchange reactions, which have the role of preventing the formation of thermodynamically favourable, highly symmetrical species in solution. [ 13 , 14 ]