Disulfide-Containing Polysiloxane with Multicolor Fluorescence and Visible-Light Excitation: Design, Synthesis, and Mechanism Exploration.

Aggregation-induced emission (AIE) polysiloxane has attracted growing attention in recent years due to its outstanding biocompatibility. However, polysiloxane usually requires high-energy UV light for excitation and exhibits monochromatic blue emission. Moreover, the experimental selection process of polysiloxane with designed features is time-consuming and laborious. So, in this paper, we developed a new molecular structure selection strategy using theoretical calculations instead of experiments, and a linear disulfide-containing polysiloxane (L1) is selected and synthesized. To our surprise, L1 can be excited by low-energy visible light (Ex = 508 nm and Em = 588 nm) and emit multicolor fluorescence under different excitation wavelengths. A further study of the luminescence mechanism was carried out through calculations about the quantum states of L1. Moreover, L1 shows multiple stimuli-responsiveness, such as redox, pH, metal ions, and solvent. This work provides an integrated route for the molecular design of macromolecular AIE luminogens with attractive fluorescence properties.