Network assembly of gold nanoparticles linked through fluorenyl dithiol bridges

Gold nanoparticles stabilized by two novel bifunctional fluorenyl thiols, generated in situ from 9,9-didodecyl-2,7-bis(acetylthio)fluorene (1) and 9,9-didodecyl-2,7-bis(acetylthiophenylethynyl)fluorene (2), exhibit bridged structures which self-assemble in parallel lines. The size, shape and structure of the AuNPs have been determined by means of dynamic light scattering (DLS), scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). AuNPs modified with fluorenyl thiol derivatives show diameters in the range of 3–7 nm. The linkage between the nanoparticles can be envisaged with the formation of dyads supported by TEM analysis and XPS measurements. Remarkably, investigation by scanning electron microscopy of the AuNP films revealed an ordered distribution of well-separated individual nanoparticles to form a 2D network. The formation of interconnected networks between AuNPs with different distances, depending on the nature of the thiol linkers (1) or (2), and the photoluminescence properties open perspectives for applications in optical devices and electronics.