Aggregation-induced emission enhancement (AIEE)-active Pt(II) metallomesogens as dyes sensitive to Hg²⁺ and dopant agents to develop stimuli-responsive luminescent polymer materials

The luminescence properties of Pt(II) compounds can be modulated by controlling the assembly of their molecules both in the solution and in the solid state. This fact constitutes a powerful tool for developing materials with stimuli-responsive luminescence properties. Herein, we describe the self-assembly behaviour of several series of Pt(II) metallomesogens in two different media upon controlled conditions. On the one hand, we explore the ability of several metal cations to induce the formation of Pt⋯Pt aggregates in solution, with the main goal of enhancing the phosphorescent emission of these compounds. On the other hand, since these compounds exhibit liquid crystalline mesophases and the temperature can control the aggregation, we have fabricated Pt(II) compound-doped polymer films and silicone membranes that show stimuli-responsive luminescent properties. In both cases, the interactions between the Pt(II) compounds and the metal cations, or the polymer matrices, play a key role in the aggregation-induced emission enhancement (AIEE) behaviour of the dyes. The effects of the alkyl chain length, the molecular asymmetry, and the nature of the ligands in the establishment of these interactions are also evaluated.