基于近红外发光的稀土-有机荧光温敏材料的构筑和研究

Temperature is one of the most important and extensively used physical parameters. The investigation related to temperature-sensing luminescent materials is active and challenging. At present, the temperature-sensing luminescent materials are generally based on the spectroscopic parameters in visible range, which is not applied to the measurements in biosystems. This project will use the lanthanide ions, such as Nd3+, Er3+, which can emit the infrared light with good transmission of the tissues, as the central metal ions and star-shaped half rigid carboxylic acid as the ligand to prepare complex with efficient visible absorption and intense infrared emission. These complexes could be served as excellent temperature-sensing materials by the way of optical thermometry. The research will focus on enhancing the infrared light emitting, increasing the stabilities of the materials and improving the sensitivity of the luminescent temperature-sensing. It contains preparing stable rare earth-organic complexes with strong infrared light emitting, exploring the relationship between the structure of the complex and the luminescent temperature-sensing and optimizing the preparing methods and parameters to get excellent luminescent temperature-sensing materials based on luminescent intensity and lifetime. In addition, the research will explore the potential application of temperature measurement in cells. This project investigating the optical thermometry based on the infrared emitting light, which open a new window for bio-system temperature sensing, is of great importance.

温度的测量非常重要，关于荧光温敏材料的研究活跃而富有挑战。目前，该类材料多利用可见光区的光谱参数随温度变化来测量或指示温度。本项目采用Nd3+，Er3+等近红外发光的稀土离子为中心离子，近星形半刚性羧酸类有机分子为配体，构筑室温至100oC温度区间的温敏配合物，使其具有可见光宽带有效激发和近红外发光强的特点。从提高材料近红外发光强度、优化温度传感灵敏度、增强样品稳定性三方面着手，通过设计、修饰有机配体，调控其三重态能级，提高敏化效率，获得近红外发光强且发光参数温度响应明显的稀土配合物，探索其结构与温敏性能的关系，进而优化基于该配合物的有机纳米复合物的制备和结构，利用发光强度、激发态寿命等光谱参数，多角度多途径研究和改善材料的荧光温敏性能，并探索该材料在生物体系温度感测中的应用。本项目研究生物穿透性优异的近红外发光的荧光温敏材料，为荧光温敏开启更有利于生物体系的检测窗口，具有重要意义。

本项目的目标是获得具有可见区宽带激发、近红外发射、荧光温敏优异的稀土有机配合物。本项目成功设计并合成了以均三苯甲酸、 四氟对苯二甲酸、3，5-吡啶二甲酸、2，2’-联吡啶-5，5’-二甲酸、2,4,6-三（4-羧基苯基）-1,3,5-三嗪为配体，以Nd3+， Er3+，Yb3+等近红外发光稀土离子为中心离子的5类稀土-有机配合物。这些样品均具有紫外可见宽带激发，近红外发射，具有优异荧光温敏的特点。我们研究了这些样品的化学组成、晶相结构、热稳定性和近红外发光的温度依赖性，并深入研究了有机配体分子与稀土离子之间的能量传递机理与效率。 基于Nd3+ 近红外区不同跃迁间的荧光强度比，Er3+: 2I13/22I15/2跃迁Stark能级间的荧光强度比、荧光寿命等，我们开发了具有深的（6mm）生物组织穿透性、高的灵敏度的近红外纳米荧光温敏材料。我们还研究了基质电荷迁移带的电子转移、能量传递及其机制，发现了某些材料中的基质电荷迁移带反常荧光温敏，并基于此开展新的研究。该项目的可量化研究成果含38篇学术论文，5项专利，重庆市优秀硕士研究生学位论文1篇，培养研究生12名，指导本科生获得省部级科技竞赛奖项20余项等。