飞秒激光作用下强双光子吸收金属配位聚合物的组装及光物理性质

Both developing new synthetic method and directed preparation of novel materials play a significant role in the field of modern high-technologies. Femtosecond laser has very low heat effect. Two-photon absorption materals can absorb low-energy photons with strong penetrability and highest spatial resolution. Based on the above considerations, we propose a novel strategy to prepare micro-nano strcuctured hybrid materials via two-photon initiated auto-polymerization process, in which metal-coordination complexes bearing strong two-photon absorption as monomer for polymerization with the aid of femtosecond laser. Firstly, small organic molecular ligands with both features of rigidity and flexibility, bearing synergistic effect, will be designed and synthesized, which can react with different series of metal ions to prepare the micro-, nano-metal clusters, metal coordiantion compounds, and coordination polymer micro-nano strcuctured materials. Secondly, the photophysical properties of the materials will be studied systematically to ascertain the relationships between the structures and properties with the aid of theroretical calculation and modern advanced determiantion technologies. These structure-effect studies include how to match the orbitals between different units in molecule, the electron transfer and energy transfer mechanisms, and two-photon absorption enhanced effect, etc. Metal coordination compounds with two-photon absorption will be investigated for the estabilishing new method of directed preparation of new materials under excitation of femtosecond laser. The materials obtained will be applied to the areas of the three-dimensional microfabrication, functional micro-device, bioimaging and sensor. The original results will be achieved in the frontier field of the two-photon absorption materials.

发展合成新方法，导向制备新材料，在当代高科技材料领域占有重要地位。本项目利用飞秒激光热效应小，利用双光子吸收材料能吸收低能量光子，穿透力强，有极高的空间分辨力等优点，以强双光子吸收金属配合物为单体，在飞秒激光作用下实现自聚合组装金属配位聚合物，制作微纳结构新材料。项目首先设计合成刚柔相济、效应协同的双光子吸收小分子有机配体，选择不同系列的金属离子，调节飞秒激光的波长、能量和频率，制备新型强双光子吸收微纳金属簇、配合物及其配位聚合物微纳结构材料；然后，利用时间分辨荧光光谱、可调谐超快速激光光谱等先进技术，结合理论计算，系统研究材料内部各基元之间轨道匹配与电子转移机制、能量传递和双光子增强效应等光物理特性，探明构效关系。建立飞秒激光作用下双光子吸收金属配合物材料导向制备的新方法，探索所得材料在三维微细加工、功能微器件、生物显影和探针方面的应用，本项目研究将在双光子吸收材料领域取得原创性成果。

项目围绕金属配合物、配位聚合物的光物理性质、构效关系及应用探索开展工作，主要成果如下：.1. 通过结构调控实现对金属有机框架特殊性质的调控，仍是一个重要的挑战。本工作设计合成了吡啶盐氧负离子全新的两性吡啶盐氧负离子化合物。发现该配体的存在与否改变着最终金属有机框架的结构，作为结构诱导剂的吡啶盐氧负离子既不与金属中心参与配位又不存在于最终的孔道结构中，这为金属有机框架后续的功能利用提供了有利的保障。2. 以噻吩为桥设计合成了D-A型配体L，与不同卤化锌进行配位，合成得到LZnCl2, LZnBr2, LZnI2和 LZn(SCN)2等4种不对称的三联吡啶锌配合物。发现该系列配合物在近红外区850 nm左右表现出理想的双光子吸收活性，为近红外非线性光学效应配合物的设计合成有重要的实验和理论依据。3. 以三苯胺为基底，设计合成了新型D–pi–A氰基有机配体，发现该有机分子表现出很强的AIEE效应，在Cd2+或Cu2+金属离子诱导下，得到具有不同形貌的纳米杂化材料；发现杂化材料的非线性光学协同效应增强、量子产率提高和荧光寿命延长。该工作为自组装制备强双光子效应纳米复合材料和应用，提供了具有科学依据。4. 设计合成了一系列新型双吡啶乙烯基苯配体，获得了两种同质异晶的晶体结构L-α 和L-beta。总结了它们的结构特点。发现它们的发光特点与分子结构和存在的环境密切相关，该研究成果为光电功能器件发光波段调制提供了科学依据。5. 以噻唑为母体，设计合成了两种具有双光子效应的D-pi-A型水溶性有机小分子（DSF和DBF）。发现两种化合物的荧光强度对环境粘度的改变具有非常明显的比率性的响应；结合理论计算，模拟了两种化合物在粘性/非粘性溶液中的荧光谱，获得了相应跃迁轨道的详细能级信息；发现DSF和DBF分别靶向于活体细胞的细胞核DNA及细胞质/核仁中的RNA，此类化合物用于生物体内的粘度灵敏检测。