Chen Hui, Ma Cheng-Bing, Hu Ming-Qiang, Wen Hui-Min, Chen Chang-Neng
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, Fujian 350002, China.
Dalton Trans. 2014 Nov 28;43(44):16737-44. doi: 10.1039/c4dt01816h.
Using 3-methyloxysalicylaldoxime (mosaoH2) and N-methyl diethanolamine (N-mdeaH2) as coligands, a family of heptanuclear Mn/Ln heterometallic compounds [Mn(II)Mn(III)2Ln(III)4(mosao)2(mosaoH)4(piv)4(N-mdea)4]·xMeCN [Ln = Dy(1), Tb(2) and Y(3), pivH = pivalic acid] have been prepared. The crystal structures of 1-3 were obtained, and their core consists of two Mn(III)Ln2(μ3-OR)2 (RO(2-) = N-mdea(2-)) triangles linked to a central Mn(II) atom. A dc magnetic susceptibility study reveals that single-ion effects of the Ln ions are dominant in compounds 1 and 2. As for compound 3, which contains diamagnetic Y ions, the magnetic interactions between Mn ions via oximate NO bridges are revealed to be ferromagnetic. Fitting of the χ(m)T vs. T data gives g = 1.96 and J = 1.12 cm(-1), affording a S = 13/2 ground state. All of the three compounds exhibit frequency-dependent out-of-phase ac susceptibility signals indicative of slow magnetization relaxation and potential SMM behavior. Among them, 1 and 3 display the out-of-phase χ"(m) peak maximum above 2.0 K. Fitting of the ac susceptibility data to the Arrhenius law gives an energy barrier U(eff) = 9.27/13.83 K for 1 and 3, respectively.
以3-甲氧基水杨醛肟（mosaoH2）和N-甲基二乙醇胺（N-mdeaH2）作为共配体，制备了一系列七核Mn/Ln异金属化合物[Mn(II)Mn(III)2Ln(III)4(mosao)2(mosaoH)4(piv)4(N-mdea)4]·xMeCN [Ln = Dy(1)、Tb(2) 和 Y(3)，pivH = 新戊酸]。获得了1-3的晶体结构，其核心由两个与中心Mn(II)原子相连的Mn(III)Ln2(μ3-OR)2（RO(2-) = N-mdea(2-)）三角形组成。直流磁化率研究表明，Ln离子的单离子效应在化合物1和2中占主导地位。至于含有抗磁性Y离子的化合物3，通过肟基NO桥的Mn离子之间的磁相互作用被揭示为铁磁性。χ(m)T对T数据的拟合给出g = 1.96和J = 1.12 cm(-1)，得到S = 13/2的基态。这三种化合物均表现出频率依赖的异相交流磁化率信号，表明存在缓慢的磁化弛豫和潜在的单分子磁体行为。其中，1和3在2.0 K以上显示出异相χ"(m)峰值最大值。将交流磁化率数据拟合到阿仑尼乌斯定律，分别得到1和3的能垒U(eff) = 9.27/13.83 K。
