Luminescent Gold(I)-Thiophenolate Coordination Polymers as Phase Change Materials and Precursors for the Formation of Multifunctional Nanocomposites
Résumé
Hybrid Au(I) compounds exhibit a large domain of applications such as electronic devices, contrast agents,
sensors or photocatalysts. These applications are related to the ability of gold(I) to form aurophilic interactions
implying self-assembly and luminescence.1 Among them, gold(I) thiolates are an important class of materials due to
the high affinity of gold for sulfur atoms that can generate oligomers or polymers. However due to the fast precipitation
and the insolubility of these solids, a little is known about their structure and the origin of the photoluminescence. We
present the syntheses and the first structure resolutions, by powder X-Ray diffraction, of series of gold(I)-
thiophenolate-based compounds. Depending on the substituent different structures are obtained: lamellar, helicoidal
or cyclic (Fig. 1a). The photophysical properties of these hybrid materials are studied in solid-state and coupled with
DFT calculations. These analyses show that the charge transfer from Ligand-to-Metal or Metal-to-Ligand and the
quantum yield from few percentage to 70%, can be tuned with the electrophilicity of the thiolates.2-3 Among those
coordination polymers, two exhibit dynamic OFF/ON emission switching, one associated with a thermally induced
solid-state phase change from amorphous to crystalline2 and the other one from a reversible
esterification/saponification. Finally we synthesized luminescent, crystalline and flexible fibers of [Au(SPh)]n and
generated by calcination composite materials mixing gold nanoparticles (GNP) and fibers (Fig. 1b and c). This study
shows the great potential of gold thiolates as phosphorescent hybrid materials and as precursors for the formation of
multifunctional nanocomposites coupling plasmonic and luminescence in electronic devices or photocatalysis.