Sulphur-containing nonaromatic polymers: clustering-triggered emission and luminescence regulation by oxidation

Abstract

Nonconventional luminophores, despite the absence of remarkable conjugations, are attracting increasing attention for their unique intrinsic emission and promising applications. The emission mechanism, nonetheless, remains elusive, which makes rational molecular design difficult. Recently, we proposed the clustering-triggered emission (CTE) mechanism to illustrate the emission. The clustering of nonconventional chromophores with π and n electrons and consequent electron cloud overlap are crucial to the luminescence. Herein, to verify it and to develop new nonconventional luminogens, a sulphur-containing polythioether (P1) was designed and synthesized through the Michael polyaddition. P1 demonstrates bright emission in the aggregates, owing to the clustering of ester groups and sulphur atoms. Furthermore, more efficient emissions are achieved through the oxidation of P1 to polysulfoxide (P2) and polysulfone (P3). Notably, different extents of oxidation also impact on the optimal emission maximum. These results indicate the possibility of fabrication and modulation of the emission of nonconventional luminophores bearing sulphur units.