Qin Lei, Zhang Zhong, Zheng Zhiping, Speldrich Manfred, Kögerler Paul, Xue Wei, Wang Bao-Ying, Chen Xiao-Ming, Zheng Yan-Zhen
Center for Applied Chemical Research, Frontier Institute of Chemistry, Frontier Institute of Science and Technology, and State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710054, China.
Dalton Trans. 2015 Jan 21;44(3):1456-64. doi: 10.1039/c4dt02599g.
An air-stable iron(ii) chain compound [Fe(phen)(Cl)2]n (, phen = 1,10-phenanthroline) was prepared and exhibits intrachain ferromagnetic interactions as well as competing interchain antiferromagnetic interactions that are mediated by π-π stacking of the phen ligands, resulting in metamagnetic behaviour. The interchain interactions can be altered by changing the external magnetic field, and disparate magnetic dynamics was thus observed from zero to the critical field of 1500 Oe. Zero-field cooled (ZFC) and field-cooled (FC) magnetization and heat capacity measurements indicate that long-range antiferromagnetic ordering occurs at lower fields, and this ordering disappears when the external field is larger than 1500 Oe. The low-frequency ac susceptibility data are consistent with the exponential increase of the temperature-dependent dc data, indicating a Glauber-type dynamics under the field of 1500 Oe. Thus, is considered as a metamagnetic single-chain magnet. For further analysis, a discrete hexametallic segment of the chain, [Fe6(phen)6(Cl)12] (), was also isolated and was shown to possess a high-spin ground state and display slow magnetic relaxations like single-molecule magnets. Magnetic analysis using CONDON suggests weak ferromagnetic interactions between the metal centres. The polymeric compound can be viewed as being constructed using the hexametallic unit which is of a low energy barrier, suggesting the significance of intrachain ferromagnetic interactions in enhancing the spin-reversal energy barrier of the short chains.
制备了一种空气稳定的铁（II）链状化合物[Fe(phen)(Cl)₂]ₙ（phen = 1,10 - 菲咯啉），该化合物表现出链内铁磁相互作用以及由phen配体的π - π堆积介导的竞争性链间反铁磁相互作用，从而导致变磁行为。链间相互作用可通过改变外部磁场来改变，因此从零到1500 Oe的临界场观察到了不同的磁动力学。零场冷却（ZFC）和场冷却（FC）磁化及热容量测量表明，在较低场中会出现长程反铁磁有序，当外部场大于1500 Oe时这种有序消失。低频交流磁化率数据与温度依赖的直流数据的指数增加一致，表明在1500 Oe场下具有格劳伯型动力学。因此，该化合物被认为是一种变磁单链磁体。为了进一步分析，还分离出了链的离散六金属片段[Fe₆(phen)₆(Cl)₁₂]，并表明其具有高自旋基态且表现出像单分子磁体一样的缓慢磁弛豫。使用CONDON进行的磁性分析表明金属中心之间存在弱铁磁相互作用。该聚合物化合物可被视为是由具有低能垒的六金属单元构建而成，这表明链内铁磁相互作用在提高短链的自旋反转能垒方面具有重要意义。
