Institute of Nanoscience and Nanotechnology, NCSR "Demokritos", 15310 Aghia Paraskevi, Athens, Greece.
Molecules. 2020 May 12;25(10):2280. doi: 10.3390/molecules25102280.
The reaction of the Schiff base ligand -OH-CH-CH=N-C(CHOH), HL, with Ni(OCMe)∙4HO and lanthanide nitrate salts in a 4 : 2 : 1 ratio lead to the formation of the trinuclear complexes NiLn(HL)(OCMe) (Ln = Sm (), Eu (), Gd (), Tb ()). The complex cations contain the strictly linear Ni-Ln-Ni moiety. The central Ln ion is bridged to each of the terminal Ni ions through two deprotonated phenolato groups from two different ligands. Each terminal Ni ion is bound to two ligands in distorted octahedral NO environment. The central lanthanide ion is coordinated to four phenolato oxygen atoms from the four ligands, and four carboxylato oxygen atoms from two acetates which are bound in the bidentate chelate mode. The lattice structure of complex consists of two interpenetrating, supramolecular diamond like lattices formed through hydrogen bonds among neighboring trinuclear clusters. The magnetic properties of - were studied. For the best fit of the magnetic susceptibility and isothermal () data gave = +0.42 cm, = +2.95 cm with g = g = 1.98. The ferromagnetic nature of the intramolecular Ni···Gd interaction revealed ground state of total spin = 11/2. The magnetocaloric effect (MCE) parameters for show that the change of the magnetic entropy (-Δ) reaches a maximum of 14.2 J kg K at 2 K. A brief literature survey of complexes containing the Ni-Ln-Ni moiety is discussed in terms of their structural properties.
希夫碱配体-OH-CH-CH=N-C(CHOH)，HL，与 Ni(OCMe)∙4HO 和镧系硝酸盐盐以 4:2:1 的比例反应，形成三核配合物NiLn(HL)(OCMe)（Ln = Sm()、Eu()、Gd()、Tb()）。配合物阳离子包含严格线性的 Ni-Ln-Ni 部分。中心 Ln 离子通过两个来自两个不同配体的去质子酚氧基桥接到每个末端 Ni 离子上。每个末端 Ni 离子以扭曲的八面体 NO 环境与两个配体结合。中心镧系离子与四个来自四个配体的酚氧基氧原子以及两个乙酸盐的四个羧基氧原子配位，以双齿螯合模式结合。配合物的晶格结构由两个相互渗透的超分子金刚石状晶格组成，通过相邻三核簇之间的氢键形成。研究了-的磁性。对于，磁导率和等温（）数据的最佳拟合给出了 = +0.42 cm，= +2.95 cm，g = g = 1.98。分子内 Ni···Gd 相互作用的铁磁性揭示了总自旋 = 11/2 的基态。对于的磁热效应（MCE）参数表明，在 2 K 时磁熵的变化（-Δ）达到最大值 14.2 J kg K。讨论了含有 Ni-Ln-Ni 部分的配合物的文献综述，从其结构性质方面进行了讨论。
