上转换发光对吡唑硼-亚铁自旋交叉体系的性能调控

Compared with the thermal-induced spin-crossover (SCO), light-induced SCO is more attractive because of short response times, low power dissipation, and high selectivity. However, the light-induced SCO at the molecular level under ambient conditions still remains a great challenge. In this project, we plan to construct the novel SCO-UCNPs (upconverting nanoparticals), through the assembly of reactive groups functionalized [Fe(H2Bpz2)2(bipy)] (H2Bpz2 = dihydrobis(1-pyrazolyl)borate, bipy = 2,2- bipyridine) complex with the rare earth ions sensitized UCNPs, for the purpose of realize both the “ligand-driven” and “light-driven” induced SCO, at the molecular level under ambient conditions. The detailed research including: 1) Rational design and prepare of reactive groups functionalized [Fe(H2Bpz2)2(bipy)] complex, and study of the structural-functional relationship; 2) Prepare and modify the rare earth ions sensitized UCNPs, then construct different SCO-UCNPs through coordination or covalent reaction; 3) Investigate the “double-driven” induced SCO, both in solution and solid state. This research, once finished, will open a new door for the practical application of SCO nanoparticals.

与热诱导自旋交叉相比，光诱导具有响应时间短、能耗低、选择性高的优点，因而更具有实用价值。然而，在单分子水平上实现常温常压下的光致自旋交叉行为依然是一个巨大挑战。本项目将活性官能团化的吡唑硼-亚铁自旋交叉体系和稀土离子敏化的上转换发光材料，通过配位或共价键反应，组装自旋交叉-上转换纳米复合材料(SCO-UCNPs)，旨在通过化学反应引起的配体场改变（配体诱导）和近红外光上转换得到的高能量光的协同影响（光诱导），在单分子水平上实现常温常压下的“双诱导”自旋交叉行为。具体研究内容为：1）活性官能团化的吡唑硼-亚铁系列结构的设计及构效研究；2）制备、修饰合适的上转换发光材料，通过不同的化学反应，组装成不同形式的SCO-UCNPs；3）分别在溶液和固体状态，考察“双诱导”对自旋交叉行为的内在调控机制和规律，筛选最优的配对组合。本项目的顺利完成对于开辟自旋交叉纳米材料实际应用的新形式具有重要意义。

本研究以自旋交叉-上转换纳米复合材料（SCO-UCNPs）的设计开发为目标，摸索最佳的上转换发光和自旋交叉能级匹配，以期在常温常压条件下，实现单分子水平上的低能量光（近红外光）致自旋交叉行为。研究内容主要包括：（a）活性官能团（羧基、氨基）化的自旋交叉体系设计、合成及性能研究；（b）超薄二维自旋交叉纳米片的制备及性能研究；（c）上转换发光对自旋交叉性能的调控。项目在（a）和（b）的研究基础之上，筛选能级匹配的六方相上转换纳米粒子，分别组装核-壳结构的上转换-自旋交叉复合纳米球（UCNPs -SCO、自旋交叉-上转换复合二维纳米材料及相关三维复合纳米材料，实现了常温常压条件下的近红外光致自旋交叉行为，这对下一代用户友好型、可穿戴、时尚的光电器件的研制奠定了良好的前期基础和理论指导。