Highly luminescent Au(I)-Thiolate coordination polymers
Résumé
Polynuclear hybrid Au(I) compounds exhibit a very large domain of applications such as electronic devices, contrast agents, sensors or photocatalysts. All these applications are related to the ability of gold(I) to form aurophilic interactions which gives luminescent materials [1]. Among gold species, thiolate gold(I) compounds are an important class of materials due to the high affinity of gold for sulfur that can generate molecular complexes, extended polymers, stabilized gold nanoparticles or SAM. Thus in nanoscience, thiolate gold(I) polymers are a key step in the Brust synthesis of functionalized gold nanoparticles. However relatively little is known about the relationship between the structure of the Au(I)-SR intermediate and the formation of the nanoparticles. Thus the luminescence of thiolate gold nanoclusters, with gold core diameter less than 2 nm, are highly dependent of the structure and the arrangement of Au(I)-thiolate motifs at the surface [2]. So to understand the luminescence and the formation of gold clusters, we will present the synthesis and the first structure resolutions by powder X-Ray diffraction of series of [Au(I)-SR]n coordination polymers. We will demonstrate that depending on the substituent (R = Ph, PhCOOH, PhNH2, PhtBu, naphthalene, C11H23, C2H4Ph
) different structures are obtained (lamellar, helicoidal or cyclic) with luminescent properties governed by Au-Au distances [3]. Reduction of these crystalline coordination polymers to form functionalized gold nanoparticles will also be reported and will contribute to a better control of gold nanoparticles preparation.