Research in the field of supramolecular chemistry has rapidly grown in recent years due to the generation of fascinating structural topologies and their associated physical properties. In order to rationally synthesize such high-dimensionality systems, several different classes of non-covalent intermolecular interactions in the crystal engineering toolbox can be utilized. Among these, attractive metallophilic interactions, such as those observed for d¹⁰gold(I), have been increasingly harnessed as a design element to synthesize functional high-dimensional systems. This tutorial review will explore the methods by which gold(I) and other d¹⁰ and d⁸ metal centres have been employed to increase structural dimensionality via the formation of metal–metal interactions. Physical and optical properties associated with metallophilicity-based supramolecular structures will also be highlighted.

A coordination polymer with the [Au(CN)₂]⁻ building block has been prepared and it exhibits weak Au(I)-mediated ferromagnetic interactions; the structure illustrates that aurophilicity is a powerful tool to increase dimensionality, generating a three-dimensional system from a 1-D polymer.

This report illustrates the concept that aurophilic interactions of gold-containing building blocks, particularly cyanoaurates, could be used as a tool to increase structural dimensionality in systems containingother metals in addition to gold(I). Such high-dimensionality systems may have useful optical, magnetic, conducting or porous materials properties. Recent successes from our group and others in using the neglected, luminescent [Au(CN)₂]⁻ building block to synthesize supramolecular coordination polymers with interesting and potentially commercially applicable physical properties will be surveyed. In most heterometallic [Au(CN)₂]-based polymers, aurophilic interactions increase the structural dimensionality of the system and can impart increased thermal stability. The gold(I) ion can mediate significant magnetic interactions between transition-metal centres or influence iron(II) spin-transition behaviour in the polymers. The Cu[Au(CN)₂]₂(solvent)_x polymer system is dynamically vapochromic, i.e., it shows large, reversible colour changes upon exposure to solvent vapours, thereby illustrating a sensor-type application. The related d⁸, square-planer [Au(CN)₄]⁻ building block, which has only recently been incorporated into coordination polymers, does not form any aurophilic interactions; weak Au-N(cyano) interactions control the intermolecular packing. Several structural examples of cyanoaurate-based coordination polymers are presented, including 2-D and 3-D arrays. The incorporation of cyanoaurates as components of advanced materials would provide a new utility and market for these key compounds of the gold mining and refining industry.