Three series of heterometallic NiII-LnIII Schiff base complexes: synthesis, crystal structures and magnetic characterization
Three series of heterometallic NiII-LnIII Schiff base complexes: synthesis, crystal structures and magnetic characterization
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三个系列的异金属Ni-II-Ln(III)席夫碱配合物：合成、晶体结构和磁性表征
DOI：
10.1039/c7dt02351k
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发表时间：
2017-10-07
影响因子：
4
通讯作者：
Yan, Shiping
中科院分区：
文献类型：
--
作者：
Jiang, Lin;Liu, Yue;Yan, Shiping
合成了三个系列的Ni-II-Ln（III）配合物，通式为[（mu（3）-CO 3）（2）{Ni（HL）中心点2CH（3）CH（2）OH（1-6）（Ln = Tb（1），Dy（2），Ho（3），Er（4），Tm（5），Yb（6）; H3 L = N，N '-双（3-甲氧基亚水杨基）-1，3-二氨基-2-丙醇），[Ni（HL）Ln（dbm）（3）]中心点CH 3OH 2中心点2CH（2）Cl（2）（7-10）（Ln = Tb（7），Eu（8），Gd（9），Ho（10）; Hdbm = 1，3-二苯基-1，3-丙二酮）和[Ni（HL）（H2O）（tfa）Ln（hfac）（2）]（11-15）（Ln = Tb（11），Dy（12），Eu（13），Gd（14），Ho（15）; Hhfac = 1，1，1，5，5，5-六氟戊烷-2，4-二酮，tfa（-）=三氟乙酸盐）。对于Ni-2（II）Ln（2）（III）系列，四核结构可以被认为是由来自大气二氧化碳的两个碳酸盐桥接的两个Ni-II-Ln（III）双核亚基。配合物1-6的Ln（III）离子为八配位的扭曲三角形十二面体几何构型，而双核配合物7-15的Ln（III）离子为九配位的扭曲松饼几何构型。采用直流和交流磁测量研究了三个系列配合物的磁性。对于Ni-II-Gd-III配合物，直流磁化率测量表明存在预期的Ni-II和Gd-III离子之间的铁磁相互作用。通过PHI软件处理的卡方T-M vs. T数据的拟合提供了9的参数g = 2.08（J = +0.87 cm（-1））和14的参数g = 2.02（J = +1.83 cm（-1））。相互作用交换与Ni-O-Gd角（α）和Ni（μ-O）Gd二面角（β）磁结构相关。在外加直流磁场下，配合物1（Tb）、2（Dy）、7（Tb）和12（Dy）表现出单一的磁弛豫，SMM参数分别为U-eff/k = 13.60 K、11.52 K、7.69 K和5.14 K。对配合物2和7的Cole-Cole图的分析表明，在弛豫过程中主要涉及单一弛豫过程，a值分别在0.37-0.17和0.14-0.11范围内。
Three series of Ni-II-Ln(III) complexes were synthesized with the general formulae [(mu(3)-CO3)(2){Ni(HL)(CH3-CH2OH) Ln(CH3COO)}(2)]center dot 2CH(3)CH(2)OH (1-6) (Ln = Tb (1), Dy (2), Ho (3), Er (4), Tm (5), Yb (6); H3L = N, N'-bis( 3-methoxysalicylidene)-1,3-diamino-2-prop-anol), [Ni(HL) Ln(dbm)(3)]center dot CH3OH2 center dot 2CH(2)Cl(2) (7-10) (Ln = Tb (7), Eu (8), Gd (9), Ho (10); Hdbm = 1,3-diphenyl-1,3-propanedione) and [Ni(HL)(H2O)(tfa) Ln(hfac)(2)] (11-15) (Ln = Tb (11), Dy (12), Eu (13), Gd (14), Ho (15); Hhfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione, tfa(-) = trifluoroacetate) using compartmental Schiff base ligands in conjunction with auxiliary ligands. For the Ni-2(II) Ln(2)(III) series, the tetranuclear structure could be considered as two Ni-II-Ln(III) dinuclear subunits bridged by two carbonates derived from atmospheric carbon dioxide. The Ln(III) ions of complexes 1-6 were octa-coordinated with distorted triangular dodecahedral geometry, while the Ln(III) ions of the dinuclear complexes 7-15 were nona-coordinated with distorted muffin geometry. The magnetic properties of the three series complexes were studied using dc and ac magnetic measurements. For the Ni-II-Gd-III complexes, the dc magnetic susceptibility measurements suggested the existence of the anticipated ferromagnetic interaction between Ni-II and Gd-III ions. The fitting of the chi T-M vs. T data processed by PHI software provided the parameters g = 2.08 (J = +0.87 cm(-1)) for 9 and g = 2.02 (J = +1.83 cm(-1)) for 14. The interaction exchange was magneto-structurally correlated to the Ni-O-Gd angle (a) and Ni(mu-O) Gd dihedral angle (beta). With an applied dc field, complexes 1 (Tb), 2 (Dy), 7 (Tb) and 12 (Dy) exhibited single magnetic relaxation with SMM parameters of U-eff/k = 13.60 K, 11.52 K, 7.69 K and 5.14 K, respectively. Analysis of the Cole-Cole plots for complexes 2 and 7 suggested that a single relaxation process was mainly involved in the relaxation process, with a values in the range of 0.37-0.17 and 0.14-0.11, respectively.