运用于三价次锕系元素分离的环肽分子设计和合成研究

The separation of the trivalent minor actinides (Am, Cm) from the lanthanides is crucial and challenging in the advanced nuclear-fuel cycles. The previously developed extractants with soft S or N-donor atoms are generally limited by the drawbacks such as low selectivity and efficiency, poor stability and accessibility, slow extraction rates, secondary pollution. Combining with modern biotechnology and organic synthesis methods, this project selects cyclopeptides as pre-organized extractants, and aims to design and develop high selective separation material from the molecular level. Meanwhile, the inherent routines between the structural parameters and the coordination /separation efficiency can be generated, which might provide new insights into the development of the extractants and lead to new molecular tools for the separation of minor actinides. . In this proposal, we planned to design the structure of cyclopeptides by combining density functional theory calculations and the fundamental coordination theories of actinides, develop the synthetic methods of unnatural amino acids with the side chain containing N, S, P or Se atoms by the transition metal catalyzed reactions, and prepare the cyclopeptides by solid-phase peptide synthesis techniques. Thereafter, we will study the extraction of Am(III) and lanthanide(III) radiotracers by the cyclopeptides to reveal the relationship between structure and separation performance, and enrich the molecular design theory. The results of this proposal are potentially important for nuclear pollution monitoring and disposal, irradiated fuel reprocessing, radioactive waste treatment etc.

三价次锕系（镅，锔）和镧系元素的分离是先进核燃料循环的关键和难点，已发展的含S或N软配位萃取剂在选择性、稳定性、萃取效率和速率、后处理、可获取性等方面存在各自的不足。本课题结合现代生化技术和有机合成方法，提出环肽作为预组织化萃取剂，从分子水平上设计高选择性分离材料，系统研究其结构信息对配位作用和分离性能的影响规律，为萃取剂的开发提供新的思路，为次锕系元素分离提供新的分子工具。. 本课题拟采用密度泛函理论计算方法和锕系元素配位化学理论对环肽结构进行合理设计；运用过渡金属催化反应，发展侧链含N、S、P和Se等软配位原子的非天然氨基酸合成方法，获取构建环肽的基本单元；利用固相多肽合成技术高效制备环肽；以镅作为目标核素，进行环肽对次锕系元素分离性能的研究，揭示环肽结构和分离性能关系，完善分子设计理论。相关研究方法和成果可运用于核污染监控和处置、乏燃料后处理、放射性废物处理等领域。

三价次锕系（镅，锔）和镧系元素的分离是先进核燃料循环的关键和难点。本课题结合现代生化技术和有机合成方法，发展环肽作为预组织化萃取剂，从分子水平上设计高选择性分离配体，系统研究其结构信息对配位作用和分离性能的影响规律，为锕系元素识别和分离提供新的分子工具。.采用密度泛函理论计算方法和锕系元素配位化学理论对环肽结构进行合理设计，设计了对锕系元素（铀、镅）具有高选择性的环肽分子；发展非活化一级和二级烷基卤代物（类卤代物）与P−H 化合物的偶联反应，可实现烷基链的磷化修饰，运用于非天然氨基酸的合成，进一步通过Fmoc-固相多肽合成技术高效制备环肽；发展了首个基于环肽的新型锕系金属传感器，可运用于铀酰离子的分析；发展了一类基于环肽的新型镧锕分离配体，可运用与三价镧锕分离；建立了可较准确预测锕系（铀酰，Am3+）元素与配体的相互作用理论计算方法。相关研究方法和成果可运用于受污环境监测，乏燃料后处理、环境修复以及锕系促排剂等领域。.