Liu Cai-Ming, Hao Xiang
Beijing National Laboratory for Molecular Sciences, Center for Molecular Science, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Omega. 2022 Jun 3;7(23):20229-20236. doi: 10.1021/acsomega.2c02155. eCollection 2022 Jun 14.
It is challenging to use achiral ligands to spontaneously construct chiral molecular magnets. In this work, two new Ln cluster complexes based on ,'-(1,3-propanediyl)bis[-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]amine] (HL) have been assembled, which are crystallized in a chiral space group due to the asymmetric distribution of acetate (OAc) groups and hexafluoroacetylacetonate (Facac) groups on both sides of the parallelogram-like Ln core. Complex , [Dy(HL)(OAc)(Facac)]·5MeOH·2HO, exhibits single-molecule magnet properties at the zero field with the / value of 48.4 K; notably, besides the Orbach process, the Raman process is also prominent for the magnetic relaxation of . Complex , [Gd(HL)(OAc)(Facac)]·4MeOH·2.5HO, displays a large magnetocaloric effect, whose largest -Δ value is 21.88 J kg K (when = 2 K and Δ = 5 T); it thus can be utilized as a good magnetic refrigeration molecular material.
使用非手性配体自发构建手性分子磁体具有挑战性。在这项工作中，基于,'-(1,3 - 丙二基)双-[1,1 - 双(羟甲基)-2 - 羟乙基]胺组装了两种新的镧系簇合物，由于乙酸根(OAc)基团和六氟乙酰丙酮根(Facac)基团在类平行四边形镧系核心两侧的不对称分布，它们在手性空间群中结晶。配合物,[Dy(HL)(OAc)(Facac)]·5MeOH·2HO，在零场下表现出单分子磁体性质，/值为48.4 K；值得注意的是，除了奥巴赫过程外，拉曼过程对于的磁弛豫也很突出。配合物,[Gd(HL)(OAc)(Facac)]·4MeOH·2.5HO，表现出大的磁热效应，其最大-Δ值为21.88 J kg K(当 = 2 K且Δ = 5 T时)；因此它可以用作良好的磁制冷分子材料。
