A series of 3d-4f heterometallic three-dimensional coordination polymers: syntheses, structures and magnetic properties

作者：Fang Ming; Shi Peng Fei; Zhao Bin^*; Jiang Dong Xue; Cheng Peng; Shi Wei

来源：Dalton Transactions, 2012, 41(22): 6820-6826.

DOI：10.1039/c2dt30391d

Seven lanthanide-cobalt heterometallic three-dimensional coordination polymers: {[Ln(3)Co(2)(BPDC)(5)(HBPDC)(H2O)(5)](ClO4)(2)center dot mH(2)O}(n) (Ln = Eu (1, m = 10.25), Gd (2, m = 8), Tb (3, m = 9.5), Dy (4, m = 11), Ho (5, m = 10.5), Tm (6, m = 11), Lu (7, m = 10.25); BPDC = 5,5'-dicarboxylate-2,2'-dipyridine anion) were structurally and magnetically characterized. Compounds 1-7 crystallize in the orthorhombic space group Pbca, featuring a 3D sandwich framework. Magnetic properties of 2-6 have been investigated by using DC (direct current) and AC (alternating current) susceptibility measurements. Among these compounds, only compound 4 displays significant frequency dependence, albeit without reaching the characteristic maxima above 2 K, implying slow magnetic relaxation behavior in 4. After the application of a DC field, good peak shapes of AC signals were obtained and the energy barrier Delta E/k(B) = 62.89 K and the preexponential factor tau(0) = 6.16 x 10(-8) s. To our knowledge, 4 has the highest energy barrier in Ln-Co SMM systems hitherto.

• 出版日期2012
• 单位南开大学