水相识别磷酸类阴离子聚降冰片烯荧光化学传感器

The development of man-made chemosensors for phosphorylated anions sensing and recognition in aqueous solutions is a hot topic in suprachemistry. Until now, the most successful approach for phosphorylated anions sensing in aqueous solutions is the utilization metal ion complexes for the specific metal ion−anion interactions. Examples with neutral hydrogen bond donors (urea, thiourea, amide, pyrrole) or positively charged binding sites (imidazolium ammonium, pyridinium, triazolium) are still rare. It was reported that the triazolium and imidazolium containing receptors often show good binding ability with phosphate anions. To increase their anions binding ability, we therefore appended these moieties into the polynorbornene backbone. Polymers have more advantages than small molecules for sensing applications, such as signal amplification and better water solubility. Herein, we will synthesis novel metal-free receptors for fluorescence sensing of phosphorylated anions. With neutral NH (urea, amide and sulfur amide) and positively charged (C–H)+ as anions binding sites, and pyrene, anthracene, naphthalene as fluorescent signals subunits, we will first synthesis a serials of acyclic and cyclic norbornene monomer, and then git their homopolymer by ring opening metathesis polymerization (ROMP) using the third generation Grubbs catalyst. The anions binding ability of polymers and their precursor monomers will be investigated by emission spectra in aqueous solution. The anions binding mechanism will further be investigated by 1H NMR titration, DFT calculation and X-ray crystal analysis. This project will provide new insight to design novel fluorescent chemosenors for phosphorylated anions recognition in aqueous solutions with high selectivity and sensitivity, and the design based on the present project can be further modified to construct more developed systems.

水相识别磷酸类阴离子化学传感器的设计与合成是超分子化学领域的研究热点与难点。目前这类受体分子主要为金属配合物，而基于氢键及静电引力作用水相识别磷酸类阴离子例子尚不多。鉴于咪唑鎓及三唑鎓受体对磷酸阴离子好的结合能力，及聚合物受体好的抗水性及易器件化特点，本申请项目拟开展具有荧光信号响应、非金属配位作用、能用于水相识别磷酸类阴离子聚降冰片烯荧光化学传感器的研究。合成出含蒽、芘、萘、丹酰氯等荧光团，单足、双足及环三唑鎓及咪唑鎓降冰片烯单体；通过开环易位聚合得到其聚合物；通过荧光光谱研究聚合物受体水溶液中磷酸阴离子识别能力；通过DLS、SEM/TEM研究聚合物受体聚集形为；通过单体核磁滴定、DFT计算研究其作用机理；揭示受体聚合物主链构型、阴离子作用点类型及数目等因素对提高磷酸阴离子水相识别能力的影响；为得到有应用前景能器件化磷酸阴离荧光化学传感器提供实验依据及理论证明。

水相识别磷酸类阴离子化学传感器的设计与合成是超分子化学领域的研究热点与难点。本项目选择降冰片烯为聚合单体，通过开环易位聚合得到侧链含不同阴离子识别位点及荧光团的阴离子聚合物受体，能用于水相及细胞内选择性识别特定的磷酸类阴离子。我们合成出了含NH及咪唑鎓/三唑鎓识别位点的均聚物P1-P5，能很好的识别ATP或GTP；含罗丹明荧光团两亲性二元共聚物P6能荧光增强识别ATP，而侧键含罗丹明、萘酰亚胺与聚乙二醇三元共聚物P7能比例荧光识别ATP。基于荧光指示剂置换原理得到聚合物P8与P9能识别ATP，而聚合物P10能用于识别Zn(II)及ATP。另外，我们还拓展了降冰片烯聚合物用于Hg(II)及生物硫醇识别及癌症的光动力治疗。详细研究了这些聚合物传感器在水溶液及细胞内对一些重要磷酸类阴离子，特别是ATP的识别能力及荧光生物成像。研究结果表明，将小分子受体高分子聚合化，确实能增强受体的离子识别选择性与灵敏度，及其水溶液中好的分散性与生物相容性。项目的完成加深了高分子聚合物化学传感器的认识，为设计合成有应用前景的荧光信号响应的阴离子化学传感器提供了实验依据及理论证明。