Long Bing-Fan, Li Yun-Lan, Zhu Zhong-Hong, Wang Hai-Ling, Liang Fu-Pei, Zou Hua-Hong
School of Chemistry and Pharmaceutical Sciences, State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources/Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), Collaborative Innovation Center for Guangxi Ethnic Medicine, School of Chemistry, and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, P. R. China.
Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin 541004, P. R. China.
Dalton Trans. 2022 Nov 15;51(44):17040-17049. doi: 10.1039/d2dt02653h.
Although progress has been made in the design and synthesis of chiral lanthanide clusters with pleasing structural connections and special shapes, assembly rules that guide their directional construction are still lacking. We reacted R/S-mandelic acid hydrazide, 2,3-dihydroxybenzaldehyde and DyCl·6HO under solvothermal conditions to obtain two octanuclear chirality clusters R-1 and S-1, which are the enantiomers of each other. R/S-mandelic acid hydrazide and 2,3-dihydroxybenzaldehyde underwent an reaction under "one-pot" conditions to generate a monohydrazone-type organic ligand R/S-mandelic acid hydrazide-2,3-dihydroxybenzaldehyde hydrazone (R/S-HL). Four R/S-HL ligands captured eight metal-centered Dy(III) ions and presented an annular arrangement, which assembled to form a pinwheel-shaped chiral cluster R/S-1. The benzene rings at the four vertices of R/S-1 can rotate freely as rotors. This is the first discovery of an annular growth mechanism during the self-assembly of lanthanide clusters. By changing the metal salt to Dy(NO)·6HO, two twist-shaped hexanuclear clusters R-2 and S-2, which are the enantiomers of each other were obtained. Four R/S-HL and two R/S-HL ligands captured six metal-centered Dy(III) ions, respectively, and were assembled through a linear growth mechanism to form the twist-shaped chiral clusters R/S-2. This is the first time that a linear growth mechanism has been proposed for the directional construction of lanthanide clusters with specific shapes. Circular dichroism results showed that R/S-1 and R/S-2 were both chiral clusters and enantiomers of each other. Magnetic studies showed that both R/S-1 and R/S-2 exhibit obvious single-molecule magnet (SMM) behaviors under zero-field conditions. This work is the first to propose an annular/linear growth mechanism for the design and synthesis of lanthanide clusters and allows the directional construction of chiral lanthanide clusters with special shapes and structural connections.
尽管在手性镧系元素簇的设计与合成方面已取得进展，其具有令人满意的结构连接和特殊形状，但仍缺乏指导其定向构建的组装规则。我们在溶剂热条件下使R/S-扁桃酸酰肼、2,3-二羟基苯甲醛与DyCl₃·6H₂O反应，得到两个八核手性簇R-1和S-1，它们互为对映体。R/S-扁桃酸酰肼与2,3-二羟基苯甲醛在“一锅法”条件下发生反应，生成一种单腙型有机配体R/S-扁桃酸酰肼-2,3-二羟基苯甲醛腙（R/S-HL）。四个R/S-HL配体捕获八个以金属为中心的Dy(III)离子并呈环状排列，组装形成风车形状的手性簇R/S-1。R/S-1四个顶点处的苯环可作为转子自由旋转。这是首次发现镧系元素簇自组装过程中的环状生长机制。通过将金属盐换为Dy(NO₃)₃·6H₂O，得到两个互为对映体的扭曲形状的六核簇R-2和S-2。四个R/S-HL和两个R/S-HL配体分别捕获六个以金属为中心的Dy(III)离子，并通过线性生长机制组装形成扭曲形状的手性簇R/S-2。这是首次针对具有特定形状的镧系元素簇的定向构建提出线性生长机制。圆二色性结果表明，R/S-1和R/S-2均为手性簇且互为对映体。磁性研究表明，R/S-1和R/S-2在零场条件下均表现出明显的单分子磁体（SMM）行为。这项工作首次提出了用于镧系元素簇设计与合成的环状/线性生长机制，并实现了具有特殊形状和结构连接的手性镧系元素簇的定向构建。
