Heterodinuclear MII–LnIII single molecule magnets constructed from exchange-coupled single ion magnets
作者:Qi-Wei Xie、Shu-Qi Wu、Wen-Bo Shi、Cai-Ming Liu、Ai-Li Cui、Hui-Zhong Kou
DOI:10.1039/c4dt00740a
日期:——
The synthesis and characterization of four dinuclear 3dâ4f complexes [MIILnIII(L)(DBM)3] (ZnDy = 1, CoY = 2, CoDy = 3·3.5CH3CN, CoGd = 4·3.5CH3CN) are reported (H2L = N,Nâ²-dimethyl-N,Nâ²-(2-hydroxy-3-methoxy-5-methyl-benzyl)ethylenediamine, DBMâ = anion of 1,3-diphenyl-propane-1,3-dione). In each of the four complexes, the MII ion occupies the internal N2O2 site whereas the LnIII ion occupies the external O4 site. There are diphenoxo bridges between the MII and LnIII ions in these complexes. The remaining coordination sites are occupied by three DBMâ anions. Direct current (dc) magnetic susceptibility measurements indicate the presence of intramolecular ferromagnetic interactions in complexes 3 and 4. The magnetic coupling constant, JCoGd, of complex 4 is estimated to be 0.26 cmâ1 (H = â2JCoGdSCoSGd). Alternating current (ac) magnetic susceptibility studies reveal that complexes 1 and 2 show field-induced single molecule magnet behavior, with ÎE values of 36.5 K and 8.56 K, respectively. Complex 3 shows frequency dependent out-of-phase signals, indicating the presence of a slow relaxation of the magnetization, whereas complex 4 does not display slow magnetization relaxation.
报道了四种双核 3d–4f 配合物 [MIILnIII(L)(DBM)3] (ZnDy = 1, CoY = 2, CoDy = 3×3.5CH3CN, CoGd = 4×3.5CH3CN) 的合成和表征 (H2L = N,N-二甲基-N,N-(2-羟基-3-甲氧基-5-甲基-苄基)乙二胺,DBM-= 1,3-二苯基丙烷-1,3-二酮的阴离子)。在四种配合物中,MII 离子占据内部 N2O2 位点,而 LnIII 离子占据外部 O4 位点。这些配合物中的 MII 和 LnIII 离子之间存在苯氧桥。其余的配位位点被三个 DBM™ 阴离子占据。直流 (dc) 磁化率测量表明配合物 3 和 4 中存在分子内铁磁相互作用。配合物 4 的磁耦合常数 JCoGd 估计为 0.26 cm−1 (H =−2JCoGdSCoSGd)。交流 (ac) 磁化率研究表明,配合物 1 和 2 显示出场感应单分子磁体行为,ΔE 值分别为 36.5 K 和 8.56 K。配合物 3 显示频率相关的异相信号,表明存在磁化缓慢弛豫,而配合物 4 不显示缓慢磁化弛豫。