Tuning of Cr–Cr Magnetic Exchange through Chalcogenide Linkers in Cr 2 Molecular Dimers
Tuning of Cr–Cr Magnetic Exchange through Chalcogenide Linkers in Cr 2 Molecular Dimers
复制标题
通过 Cr2 分子二聚体中的硫属化物连接基调节 Cr–Cr 磁交换
DOI：
10.1021/acs.inorgchem.2c00298
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发表时间：
2022
影响因子：
4.6
通讯作者：
Kovnir, Kirill
中科院分区：
文献类型：
--
作者：
Gamage, Eranga H.;Ribeiro, Raquel A.;Harmer, Colin P.;Canfield, Paul C.;Ozarowski, Andrew;Kovnir, Kirill
采用溶剂热法合成了三种单原子硫族桥连的铬二聚体化合物Cr2 Q2（en）4X 2（Q：S，Se;X：Br，Cl;en：乙二胺）。硫族化合物连接体介导Cr 3+中心之间的磁交换，而双齿乙二胺配体完成Cr中心的扭曲八面体配位。与先前报道的化合物不同，没有硫族化物原子连接到额外的配体。磁化率研究表明，Cr 3+中心之间的反铁磁耦合，这是中等的Cr2 Se 2（en）4X 2和更强的Cr2 S2（en）4Cl 2。磁测数据的拟合需要一个双二次交换项。高频EPR谱显示的特征信号，由于耦合S = 1自旋态可以解释的“巨自旋”的哈密顿量。第四种化合物Cr2 Se 8（en）4具有连接两个Cr 3+中心的单个双原子Se桥，并且显示出弱的铁磁交换相互作用。这项工作表明，通过操纵原子间的距离和桥接硫族化物连接体的数量的金属中心之间的交换相互作用的强度和类型的可调性。
A set of three Cr-dimer compounds, Cr2Q2(en)4X2(Q: S, Se;X: Br, Cl;en: ethylenediamine), with monoatomic chalcogenide bridges have been synthesized via a single-step solvothermal route. Chalcogenide linkers mediate magnetic exchange between Cr3+centers, while bidentate ethylenediamine ligands complete the distorted octahedral coordination of Cr centers. Unlike the compounds previously reported, none of the chalcogenide atoms are connected to extra ligands. Magnetic susceptibility studies indicate antiferromagnetic coupling between Cr3+centers, which are moderate in Cr2Se2(en)4X2and stronger in Cr2S2(en)4Cl2. Fitting the magnetic data requires a biquadratic exchange term. High-frequency EPR spectra showing characteristic signals due to coupledS= 1 spin states could be interpreted in terms of the “giant spin” Hamiltonian. A fourth compound, Cr2Se8(en)4, has a single diatomic Se bridge connecting the two Cr3+centers and shows weak ferromagnetic exchange interactions. This work demonstrates the tunability in strength and type of exchange interactions between metal centers by manipulating the interatomic distances and number of bridging chalcogenide linkers.