论文部分内容阅读
本文以对叔丁基杯[8]芳烃(H8C8A)为配体,在溶剂热条件下制得了三个十四核的3d-4f化合物[LnIII6CoII8(C8A)2(O)2(OH)4(CO3)2(HCOO)2(CH3COO)4(DMF)m(H2O)n]·pDMF·qH2O(其中DMF=N,N′-二甲基甲酰胺;1:Ln=Sm,m=8,n=6,p=1,q=5;2和3:Ln=Gd(2)或Dy(3),m=10,n=4,p=0,q=7).X射线单晶测试表明,化合物结构中,杯[8]芳烃呈双锥式构型,每个锥式空腔下缘结合一个稀土离子,两个钴离子位于双锥的连接处,形成一个Ln2Co2-C8A四核单元,两个四核单元通过两个稀土离子连接形成环状结构,加上另外四个配位的钴离子,形成Ln6Co8核簇.磁性研究表明:化合物2在?H为7T,温度为4K时熵变值为14.83Jkg?1K?1,化合物3在低温下表现出频率依赖特性.
Three tetranuclear 3d-4f compounds [LnIII6CoII8 (C8A) 2 (O) 2 (OH) 4 (H4C8A) were synthesized under solvothermal conditions using p-tert- (DMF) m (H2O) n] · pDMF · qH2O (where DMF = N, N’-dimethylformamide; 1: Ln = Sm, m = 8, n = 6, p = 1, q = 5; 2 and 3: Ln = Gd (2) or Dy (3), m = 10, n = 4, p = 0, q = In the compound structure, calix [8] arene has a double conical configuration. One rare earth ion is attached to the lower edge of each conical cavity. Two cobalt ions are located at the junction of the double cones to form a tetragonal unit of Ln2Co2-C8A. The two tetragonal units are connected by two rare earth ions to form a ring structure, plus the other four coordinated cobalt ions, forming Ln6Co8 core clusters. Magnetic studies show that: Compound 2 at? H of 7T, temperature of 4K entropy change The value of 14.83Jkg? 1K? 1, Compound 3 showed frequency-dependent characteristics at low temperature.