高效三线态敏化可见光光致变色染料及稳定性提升

Recent research hotspot on photochromic dyes includes invention of efficient visible light photochromic dyes with enhanced stability as well as their performances promotion and application expansion. Focused on issues of low stability and performances of currently developed visible light photochromic dyes, this proposal would raise an innovative strategy based on triplet-sensitized photochromism to achieve both visible light excitation and stability enhancement. By introducing narrow singlet-triplet energy gap dyes as triplet sensitizers, the triplet energy levels between diarylethene photochromic dyes and sensitizers can be easily matched with great flexibility, which is crucial for highly efficient visible light photochromism. Meanwhile, the triplet sensitizers could be considered as stabilizers, since the triplet sensitization blocks the photo-byproduct pathway and greatly enhances the stability of photochromic dyes. Based on these newly developed photochromic dyes, we intend to further improve the stability and photochromism of dyes by reducing the oxygen-induced quenching effect and dispersion effect via inclusion, polymerization and crystallization.

高稳定性、高效可见光光致变色染料的创制、实现光致变色功能染料性能提升及应用拓展，是当今光致变色染料领域的研究热点。本项目拟针对可见光光致变色染料开发过程中存在的稳定性差、性能提升受限等问题，创新性的提出高效三线态敏化可见光光致变色策略，在实现可见光光致变色性能的同时，增强染料稳定性、兼顾提升光致变色各项性能。本项目拟采用窄单-三线态带隙染料作为三线态敏化剂，灵活匹配敏化剂与二芳基乙烯光致变色染料三线态能级，实现高效、简单可行的长波长可见光光致变色。同时，以三线态敏化剂作为稳定剂，阻断光副反应的通路，提升染料的稳定性。在新染料创制的基础上，通过包结、聚合、结晶等方式进一步降低氧气对三线态的淬灭效应、排除扩散效应，大幅提升染料的稳定性和光致变色效率。

高性能光致变色染料的创制和应用是精细化工产品工程学的前沿研究课题。光致变色染料以其高时空分辨及非侵入调控特性，近年来在生物医药、分子存储、光电器件等新兴领域备受关注。传统光致变色染料主要由紫外光驱动，存在光毒性强、高能耗、组织穿透性差等缺陷，其在生物医药、智能材料等领域的应用受限。因此，创制可见光光致变色染料是目前本领域的研究焦点之一。现有可见光光致变色染料设计主要基于共轭延伸的单线态激发策略。该策略存在染料激发波长与光控性能相互制约的弊端，造成染料稳定性差、光量子产率低、制备复杂等问题，极大限制了光致变色染料的新应用探索。本项目创新提出“三线态敏化”光致变色新机制，开发高性能可见光光致变色染料创制新策略（400-500 nm）。该策略规避了传统的共轭延伸法分子内电子云重排的问题，并有效阻断光副反应通路，成功实现了染料可见光激发和光调控性能（光量子产率>40%、转化率>85%、抗疲劳性：50次循环损耗<5%）的协同提升，为创制高性能光致变色染料奠定了基础。基于三线态敏化空间能量传递特性与能级匹配的灵活性，发展了光致变色染料“砌块化”高效制备方法，为应用导向的染料功能化修饰提供了有利条件。项目进一步通过染料生物分子功能化等方法，优化染料水溶性和生物相容性，发展了可用于细胞超分辨成像的光控分子探针。光致变色染料特有的“明/暗（ON/OFF）态”光调控作为STORM超分辨成像的理想手段，实现了疾病标志物细胞器特征分布的精准成像（分辨率50-70 nm），探索了染料高时空分辨生物成像新应用。