A luminescent double helical gold(i)–thiophenolate coordination polymer obtained by hydrothermal synthesis or by thermal solid-state amorphous-to-crystalline isomerization

Abstract

A gold(I)–thiophenolate coordination polymer, [Au(SPh)]_n, has been synthesized by employing hydrothermal conditions at 120 °C. This new synthesis led to isolate highly crystalline compound and to solve its structure from powder X-ray diffraction patterns. The compound forms double interpenetrated helical chains stabilized through C–H⋯π and aurophilic bonds. The solid is phosphorescent at room temperature and in the solid-state with a quantum yield of around 5%. Thanks to DFT calculations, the emission is attributed to a Ligand-to-Metal–Metal Charge Transfer (LMMCT) transition with a small contribution from a Metal Centered (MC) transition. In addition to this hydrothermal reaction, it is possible to obtain this [Au(SPh)]_n coordination polymer by a two-step synthesis which is a thermally-induced solid-state amorphous-to crystalline isomerization. This transition has been followed by powder X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and also from the appearance of phosphorescence upon heating.