Controlling the Molecular Assembly of Polyoxometalates from the Nano to the Micron Scale: Molecules to Materials

Abstract

AbstractPolyoxometalates (POMs) represent a class of metal‐oxide units based upon oxides of Mo, W, V, and Nb. Such cluster building blocks can also be subsequently self‐organized in complex 1D, 2D, and 3D frameworks leading to functional materials with diverse properties that span size ranges from 1 to 7 nm in terms of the size of the largest molecular units/clusters. However, since the cluster building blocks have great structural flexibility, the design of architectures is non‐trivial due to the sensitive dependence on reaction parameters such as pH, cation type, temperature, templating and linking units, ionic strength, redox agents. Therefore, the ability to control the aggregation or linking of the building blocks to give pre‐defined structure‐types as well as engineering the physical properties — for example, optical, electronic, catalytic activity/reactivity — is a tremendous challenge. In this review we survey our work from the control/design point of view and show how it is becoming possible to control the assembly of POM‐based architectures. We also describe the polyoxometalate‐based molecules‐to‐material transformations that can be seen as an osmotically driven crystal morphogenesis producing tubular architectures. This can be described as a new type of emergent phenomenon.