新型环状氮氧自由基功能分子的设计合成及其磁性和辐射防护效应研究

Molecule-based magnets has many advantages comparing with traditional magnetic materials, which becomes one of the hot spots in the field of chemistry, physics, materials and life sciences. On the basis of our preliminary studies, this project will focus on design and synthesis of novel three series of pure organic nitroxides free radicals and their metal complex, bearing nitrogen heterocyclic ring, from easily available starting material. Their magnet properties and the effects of radiation protection will be intensively investigated. Our objective is to obtain some good moleculars with excellent magnetic properties or radiation protection abilities. Moreover, based on the experimental data, we will attempt to summarize some of the structure-activity relationship. The nitrogen heterocyclic ring contains the characteristics of crown ethers, cyclodextrins, and multidentate ligands, which can form supramolecular systems and present a special performance by selective inclusion of many guest molecules. This project will synthesize a series of these special novel nitroxides free radicals based on the special nitrogen heterocyclic ring, which is expected to exceed the bottlenecks of the research of nitroxides free radicals. We believe this project is valuable, important and have many potential applications.

分子基磁体具有传统磁性材料无法比拟的优越性，是目前化学、物理、材料、生命科学等诸多领域的研究热点。本课题在前期研究基础上，针对氮氧自由基型纯有机分子磁体和自由基-配合物型分子磁体目前存在的问题，结合近年来超分子领域发展起来的氮杂环番结构，以价廉易得的原料设计合成三组环状多氮氧自由基型纯有机分子磁体，并通过和顺磁性金属配位,得到自由基-配合物型分子磁体。通过研究氮氧自由基分子及其配合物的磁学性质，以及这些分子的辐射防护效应，筛选出磁学特性好或辐射防护效果显著的氮氧自由基分子，并阐明结构包括自由基个数、共轭、手性因素对磁学性质和生物活性的影响，为新型功能氮氧自由基设计提供实验数据和理论指导。本课题创新性地将兼备冠醚、环糊精和多齿配体特性的氮杂环番结构引入氮氧自由基分子的构建中，有望突破有机分子磁体目前研究的瓶颈，为制备氮氧自由基型分子磁体提供一种全新思路，具有重要的科学理论价值和潜在应用前景。

以酒石酸、1,2-二苯基乙二胺、四氮杂十二烷等为原料，按计划完成了四组氮氧自由基的合成工作，分别用元素分析、IR、UV-Vis、HRMS、EPR 光谱手段对其进行了结构表征；将4ab与Mn(hfac)2配位，合成了过渡金属配合物Mn(hfac)2 Cy（7），通过 IR、UV-Vis、电化学等方法对该配合物进行了鉴定，测定了该配合物的变温磁化率和居里温度；在完成上述计划氮氧自由基及磁学性质考察的基础上，我们还根据前期的经验教训，设计、合成了以没食子酸、阿魏酸、咖啡酸、肉桂酸等含酚羟基的天然羧酸为母核的8种新型Tempol类氮氧自由基，并通过IR、UV-Vis、1H NMR、13C NMR、HRMS、EPR 等手段对这些自由基及其中间体进行了结构确证，通过细胞实验和动物实验，初步筛选出辐射防护效果良好的氮氧自由基分子，为进一步进行药物研发提供实验数据。