Counteranion Modulated Crystal Growth and Function of One-Dimensional Homochiral Coordination Polymers: Morphology, Structures, and Magnetic Properties.
Counteranion Modulated Crystal Growth and Function of One-Dimensional Homochiral Coordination Polymers: Morphology, Structures, and Magnetic Properties.
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DOI：
10.1021/acs.inorgchem.8b01762
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发表时间：
2018-09
影响因子：
4.6
通讯作者：
Yan Xu;You-sheng Yu;Xin‐Da Huang;S. Bao;Hong-ming Ding;Yu-qiang Ma;Li‐Min Zheng
中科院分区：
文献类型：
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作者：
Yan Xu;You-sheng Yu;Xin‐Da Huang;S. Bao;Hong-ming Ding;Yu-qiang Ma;Li‐Min Zheng
合成了四对对映体镝（III）膦酸盐，即R-或S-[Dy 3（pempH 2）2（pempH）7]2（NO3）4·12 H2O（R-1或S-1），R-或S-[Dy 3（pempH）7（pempH 2）2] Cl 2·2 H2O（R-2或S-2）、R-或S-[Dy 3（pempH）7（pempH 2）2] Br 2·2 H2O（R-3或S-3）和R-或S-[Dy 11（pempH 2）6（pempH）27]（CF 3 SO 3）6·22 H 2 O（R-4或S-4），其中R-或S-pempH 2代表R-或S-（1-苯乙基）氨基]甲基膦酸。所有显示纯手性链结构，电荷平衡的抗衡阴离子。通过对R-异构体晶体形貌的比较发现，四种化合物的总体形状非常相似，但长径比的变化顺序为：R-1 < R-2 < R-3 < R-4。该序列与不同抗衡阴离子相关的链间相互作用的降低一致，这是通过分子模拟合理化的。抗衡阴离子还影响DyIII离子的链内结构和局部配位环境。结果表明，化合物R-2和R-3在零直流电场下表现出明显的双弛豫过程，其慢弛豫和快弛豫的有效势垒分别为79.1和37.6 K，R-3分别为80.0和39.1 K.对于化合物R-1和R-4，在零直流磁场下也观察到缓慢的磁弛豫，但在1.8K以下没有出现最大值。
Four pairs of enantiomeric dysprosium(III) phosphonates, namely, R- or S-[Dy3(pempH2)2(pempH)7]2(NO3)4·12H2O ( R-1 or S-1), R- or S-[Dy3(pempH)7(pempH2)2]Cl2·2H2O ( R-2 or S-2), R- or S-[Dy3(pempH)7(pempH2)2]Br2·2H2O ( R-3 or S-3), and R- or S-[Dy11(pempH2)6(pempH)27](CF3SO3)6·22H2O ( R-4 or S-4) are reported, where R- or S-pempH2 represent R- or S-(1-phenylethyl)amino] methylphosphonic acid. All show homochiral chain structures, charge-balanced by counteranions. A comparison of the crystal morphologies of the R-isomers reveals that the overall shapes are quite similar for the four compounds, but the aspect ratio changes remarkably following the sequence: R-1 < R-2 < R-3 < R-4. The sequence is in agreement with the decreasing interchain interactions related to different counteranions, which is rationalized by molecular simulations. The counteranions also influence the intrachain structures and the local coordination environments of the DyIII ions. As a result, compounds R-2 and R-3 exhibit distinct dual relaxation processes at zero dc field with the effective energy barriers for the slow- and fast-relaxation being 79.1 and 37.6 K for R-2, and 80.0 and 39.1 K for R-3, respectively. For compounds R-1 and R-4, however, slow magnetic relaxation is also observed at zero dc field but without the appearance of maxima down to 1.8 K.