Gold Nanowired: A Linear (Au25)n Polymer from Au25 Molecular Clusters

Au-25(SR)(18) has provided fundamental insights into the properties of clusters protected by monolayers of thiolated ligands (SR). Because of its ultrasmall core, 1 nm, Au-25(SR)(18) displays molecular behavior. We prepared a Au-25 cluster capped by n-butanethiolates (SBu), obtained its structure by single-crystal X-ray crystallography, and studied its properties both experimentally and theoretically. Whereas in solution Au-25(SBu)(18)(0) is a paramagnetic molecule, in the crystal it becomes a linear polymer of Au-25 clusters connected via single Au-Au bonds and stabilized by proper orientation of clusters and interdigitation of ligands. At low temperature, (Au-25(SBu)(18)(0)](n) has a nonmagnetic ground state and can be described, as a one-dimensional antiferromagnetic system. These findings provide a breakthrough into the properties and possible solid-state applications of molecular gold nanowires.