Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China.
State Key Laboratory of Rare Earth Resource Utilization , Changchun Institute of Applied Chemistry, Chinese Academy of Sciences , Changchun 130022 , China.
Inorg Chem. 2020 Jan 6;59(1):443-451. doi: 10.1021/acs.inorgchem.9b02739. Epub 2019 Dec 17.
Profiting from a multicoordinating nitronyl nitroxide radical, i.e. a functionalized nitronyl nitroxide biradical ligand, a family of novel tetranuclear lanthanide complexes, formulated as [RE(hfac)(NITPhO-3Pybis)] (RE = Gd , Tb , Dy , Ho , and Y ; NITPhO-3Pybis = 5-(3-pyridinyloxy)-1,3-bis(1'-oxyl-3'-oxido-4',4',5',5'-tetramethyl-4,5-hydro-1-imidazol-2-yl)benzene; hfac = hexafluoroacetylacetonate) were successfully constructed and characterized. In these complexes, the designed functionalized nitronyl nitroxide biradical ligand functions as the chelating and/or bridging ligand to bind the lanthanide ions, resulting in tetranuclear octa-spin lanthanide complexes with a circle-shaped arrangement. Direct-current magnetic data show that antiferromagnetic interaction dominates in the Gd derivative, while ferromagnetic coupling plays a leading role in complex Y, in which the relevant magnetic exchange parameters were obtained through applicable magnetic models. Dynamic magnetic studies of Tb and Dy analogues exhibit apparent frequency-dependent out-of-phase signals, which are typical features for slow magnetic relaxation behavior. The values of and τ were obtained as follows: = 10.5 K and τ = 6.6 × 10 s for the Tb complex and = 5.2 K and τ = 2.5 × 10 s for the Dy compound. Intriguingly, the butterfly shaped hysteresis loop is found for the Tb analogue. Guided by fluorescence spectra, the representative peaks are identified for the Tb derivative.
从一个多配位的硝酰基氮自由基（即功能化的硝酰基氮双自由基配体）中获利，我们成功构建并表征了一系列新型四核镧系金属配合物，其化学式为[RE(hfac)(NITPhO-3Pybis)]（RE = Gd、Tb、Dy、Ho 和 Y；NITPhO-3Pybis = 5-(3-吡啶氧基）-1,3-双(1'-氧-3'-氧代-4',4',5',5'-四甲基-4,5-氢-1-咪唑-2-基）苯；hfac = 六氟乙酰丙酮酸盐）。在这些配合物中，所设计的功能化硝酰基氮双自由基配体作为螯合和/或桥联配体与镧系金属离子结合，形成具有圆形排列的四核八自旋镧系金属配合物。直流磁数据表明，反铁磁相互作用在 Gd 衍生物中占主导地位，而铁磁耦合在 Y 配合物中起主导作用，其中通过适用的磁模型获得了相关的磁交换参数。Tb 和 Dy 类似物的动态磁研究显示出明显的频率相关的反相信号，这是慢磁弛豫行为的典型特征。获得了以下 值和 τ 值：对于 Tb 配合物， = 10.5 K 和 τ = 6.6 × 10 s；对于 Dy 化合物， = 5.2 K 和 τ = 2.5 × 10 s。有趣的是，在 Tb 类似物中发现了蝴蝶形磁滞回线。在荧光光谱的指导下，确定了 Tb 衍生物的代表性峰。
