基于糖化合物“Ferrier Carbocyclization”汞离子荧光探针的设计、合成及性能研究

Mercury is one of the most hazardous species in nature, which may cause prenatal brain damage, cognitive and motion disorders, vision and hearing loss, and even death. Development of facile and selective method for Hg2+ detection has long been demanded in the area of food safety and environmental protection.A number of fluorescent chemosensors for the selective detection of Hg2+ ions have been reported.However, only few successful examples of fluorescent probes for detecting Hg2+ ions in aqueous solutions or pure water have been established, and thus hampered the analytical application in real water samples. In this research program, we will design and synthesize sugar functionalized fluorescent probes based on the highly selective mercury-mediated Ferrier carbocyclization. The introduction of sugar residues in fluorescent probe can greatly improve its water solubility and bio-compatibility, thus the synthesized sugar-fluroscent probes can be used directly in 100% water media to detect the content of Hg2+ in real ambient water samples,cells and living organisms. In addition, we will develop novel fluorophores with high quantum yield to enhance the sensitivity of the new fluorescent probes.We hope the designed fluorescent probes would provide a convient method for visible and real-time detection of Hg2+ with highly selectivity and excellent sensitivity in 100% water media.What'more, we will put the Hg2+ probes into materials in order to make the synthesized probes employed for real application.

汞是毒性最大的重金属之一。具有较强的腐蚀性和致癌性，能对人体器官产生较大的损伤。目前，多种检测汞离子的荧光探针已被报道，特别是有机小分子荧光探针，但普遍水溶性差，都需要有机溶剂作为助溶剂，都不能在100%水溶液中实现对汞离子的检测等弊端，限制了他们的潜在应用。本项目拟从有机化学角度，通过改善荧光团的结构和性质，提高其荧光强度，从而提高荧光探针的检测灵敏度；再结合汞离子专一诱导的 "Ferrier carbocyclization"反应，设计合成高选择性、高灵敏度、"turn-on"糖类汞离子荧光探针。利用糖的水溶性，使荧光探针在100%水溶液中实现对汞离子的检测；同时利用糖的生物相容性，细胞表面的糖转运蛋白对糖的主动转运，将荧光探针带入到细胞内，在完全生理条件下，100%水溶性的荧光探针也能在细胞和生物体内检测汞离子；并研究荧光探针潜在的应用价值，使其材料化，最终达到实际应用的目的。

选择合适的荧光团（荧光强度强、pH值的敏感范围宽、大斯托克斯位移等）结合糖类专一诱导的化学反应，设计合成高选择性、高灵敏度、“turn-on”糖类汞离子荧光探针。利用糖的水溶性，生物相容性，细胞表面的糖转运蛋白对糖的主动转运，将荧光探针带入到细胞内，在完全生理条件下，100%水溶性的荧光探针也能在细胞和生物体内检测汞离子或其他离子。另外，利用廉价易得的、具有特殊官能团结构的噻吩，噻唑，氨基酸及其衍生物作为识别基团，设计合成一系列结构新颖的荧光探针，对不同种类的离子也有很好的选择性和灵敏度。. 本项目发现了多个汞离子，pH，铜离子，三价铁离子，锡离子，硫化氢小分子，亚硫酸根离子荧光探针，都具有很高的选择性和检测灵敏度，并实现了细胞内的在线检测，具有潜在的实际应用前景。这些荧光探针的实际应用还在探索研究中，实现探针的材料化，便携化，将会对汞离子或者其他活性离子实现实时，在线现场检测，大大方便了检测和监管。