基于罗丹明衍生物与过渡金属配合物的双发色双发光传感体系

The development of optical signaling systems for various chemosensors to detect different types of analyte has received considerable attention in the past few decades. Design of sensors based on changes in luminescence is a promising field and appears to be particularly attractive due to their simplicity, high sensitivity, high selectivity, and instantaneous response by simple luminescence enhancement or quenching. In recent years, much attention have been paid to the design of various luminescent transition metal cation chemosensors as they could provide an easy spectrochemical and luminescence handle for the selective and specific monitoring of substrates. Recent studies showed that rhodamine-based derivatives can function not only as a highly receptor but also as a chromophoric and fluorophoric reporter at the same time. In view of its highly selective and sensitive nature, the family of rhodamine-based derivatives is anticipated to be a promising candidate for its utilization as a selective receptor. Of particular interest to us is the possibility that incorporation of rhodamine derivative into a luminescent transition metal complex may allow access to a variety of new bichromophoric sensory systems. In this project, different types of luminescent transition metal complex systems hybridized with organic rhodamine fluorophore through a bridging spacer will be designed and synthesized. Their electronic absorption, luminescence and sensory behaviors will be explored and correlations with the nature of the transition metal complexes, rhodamine derivatives and bridging spacers will be made. The present project aims to explore the use of various transition metal complexes coupled to the rhodamine derivative with selective sensory functionality. In view of the advantages of the transition-metal complex with their wide tunability of emission energy, large Stokes shift, long luminescence lifetime, synthetic versatility and photo- and chemical stabilities, together with the low-energy absorption of rhodamine for the excitation which would be beneficial with less photobleaching of the chemosensor or photodegradation of the biological samples in the process of detection, extension of the work to biological activities acting as luminescent bioimaging agents will also be explored. The present project may open up new avenues for the fundamental understanding of the photophysical and selective sensory behaviors and the design of a new chemosensor system with the hybridization of the organic fluorophoric rhodamine and the luminescent transition metal complex.

罗丹明衍生物的化学传感器不仅能作高灵敏度和高选择性的接受器，同时亦是发色和发光报告器。另一方面，过渡金属发光配合物有着多项优点，适用于设计及发展过渡金属发光传感器，能与有机发光体互补。由于一直没有利用罗丹明衍生物与过渡金属发光配合物构建双发色、双发光传感器的相关研究。因此本课题拟将过渡金属配合物引入罗丹明结构之中，以构建一类具有两个发光基团的双发色双发光杂交分子体系，并进行详细的结构表征、光物理性质研究。通过合理设计和适当选择过渡金属中心、含罗丹明的配体、罗丹明与过渡金属配合物之桥梁间隔和长度等结构修饰，可以调整这类体系的光谱性质、传感选择性和敏感度、能量转移效率与方向，获得新颖的具有发光和高选择性的双发色、双发光传感器体系。用于制备具有调节特性的有机-无机分子开关，具有很好的挑战性和研究前景。除可提供更有价值的视角来理解上述变化的光谱起源，也打开了探索新探针的方便之门。

在过去的几十年中，各种化学传感器的光学信号系统的开发受到了相当多的关注。 基于发光变化的传感器的设计是一个很有前途的领域，并且由于其简单，高灵敏度，高选择性和通过简单的发光增强或淬火的瞬时响应而显得特别有吸引力。其中罗丹明衍生物的化学传感器不仅能作高灵敏度和高选择性的接受器，同时亦是发色和发光报告器。另一方面，过渡金属发光配合物有着多项优点，适用于设计及发展过渡金属发光传感器，能与有机发光体互补。但一直没有利用罗丹明衍生物与过渡金属发光配合物构建双发色、双发光传感器的相关研究。.本项目中，我们选择罗丹明衍生物与过渡金属配合物作为研究对象，通过分子设计和调节合成新型的含有罗丹明单元的有机配体，利用得到的配体与过渡金属配位获得罗丹明与过渡金属配合物的杂交分子，并详细系统地研究它们的电子吸收光谱、发光性、电化学性质等。在项目开展过程中，我们首先设计合成了14种含罗丹明的有机配体，以及合成了含有两个螺环结构的具有独立双发光性能的荧光素/罗丹明化合物RhOH。RhOH对Hg2+有一定的选择性。在罗丹明有机配体的基础上引入过渡金属，成功开发了Hg2+高选择性的罗丹明三联吡啶铂配合物探针1、2，还合成了对OCl-具有高选择性的香豆素/罗丹明类荧光探针6，以及开发了罗丹明/荧光素类荧光探针3、4作为共聚焦荧光检测的显像剂应用于化学及生物检测领域。此外，罗丹明配体L5在螺环修饰成酰肼bPyRhBN之后，用作N^N配体与有着不同C^N配体的二聚铱配合物反应，制备得到三价铱配合物I、II。同时我们还开发了M-Rho用作线粒体靶向光敏剂，对肿瘤细胞具有良好的选择性，其光触发PDT效应可根除肿瘤，此项研究在医疗领域对于肿瘤的治疗具有积极的意义。