Kinked-Helix Actinide Polyrotaxanes from Weakly Bound Pseudorotaxane Linkers with Variable Conformations
Kinked-Helix Actinide Polyrotaxanes from Weakly Bound Pseudorotaxane Linkers with Variable Conformations
复制标题
来自具有可变构象的弱结合拟轮烷连接体的扭结螺旋锕系聚轮烷
DOI：
10.1021/acs.inorgchem.0c00037
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发表时间：
2020
影响因子：
4.6
通讯作者：
Shi Wei-qun
中科院分区：
文献类型：
--
作者：
Li Fei-ze;Mei Lei;An Shu-wen;Hu Kong-qiu;Chai Zhi-fang;Liu Ning;Shi Wei-qun
在金属-有机配位聚合物中引入机械互锁分子如准轮烷，可以得到许多具有特殊结构和独特性能的新型杂化材料。本论文以弱键合的葫芦[6]脲（CB[6]）-联吡啶类轮烷作为超分子前体，与铀酰进行组装，构建了具有有趣结构的铀酰-轮烷配位聚合物（URCPs）。通过调整合成条件，得到了一个新的扭折螺旋铀酰轮烷化合物（URCP 3），以及另外三个从一维链状到二维交织网状结构的化合物URCP 1、URCP 2和URCP 4。详细的结构分析表明，伪轮烷配体（C8BPCA@CB[6]）在URCP的构建中显示出很大的构型多样性，这很可能是由于主体和客体分子之间的弱结合强度。具体地，基于C8 BPCA的末端羧基的单齿配位被周围的单向螯合的草酸盐所迫，整个柔性假轮烷接头将更可能经历构象变化，从而从铀酰赤道面的两侧结合到铀酰中心，并促进形成URCP 3的扭结螺旋结构，其形状像中国结沿着[001]。本工作丰富了锕系轮烷化合物库，也为利用弱键合的准轮烷构建复杂结构的金属有机化合物提供了新的途径。
The incorporation of a mechanically interlocked molecule such as pseudorotaxane into metal–organic coordination polymers has afforded plenty of new hybrid materials with special structures and unique properties. In this work, we employ a weakly bound cucurbit[6]uril (CB[6])-bipyridinium pseudorotaxane as a supramolecular precursor to assemble with uranyl, aiming to construct uranyl-rotaxane coordination polymers (URCPs) with intriguing structures. By adjusting the synthetic conditions, a new kinked-helix uranyl rotaxane compound (URCP3), together with three other compoundsURCP1,URCP2, andURCP4varying from 1D chains to 2D interwoven networks, was obtained. Detailed structural analyses indicate that the pseudorotaxane ligand (C8BPCA@CB[6]) shows great configuration diversity in the construction of URCPs, which is most probably due to the weak binding strength between the host and guest molecules. Specifically, based on the monodentate coordination of the end carboxyl groups ofC8BPCAforced by the surrounding unilaterally-chelated oxalate, the entire flexible pseudorotaxane linker will be more likely to undergo conformational change, thereby binding to the uranyl center from both sides of the uranyl equatorial plane and promoting the formation of a kinked helix structure ofURCP3that is shaped like a Chinese knot along [001]. This work enriches the library of actinide-rotaxane compounds and provides a new approach to construct metal–organic compounds with complicated structures using weakly bonded pseudorotaxanes as well.