Song Hongwei, Jin Chaoyi, Wang Xiaotong, Xie Junfang, Ma Yue, Tang Jinkui, Li Licun
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.
Dalton Trans. 2024 Jun 10;53(23):10007-10017. doi: 10.1039/d3dt04360f.
By employing nitronyl/imino nitroxide biradicals, three Ln-Zn complexes, namely, [LnZn(hfac)(ImPhPyobis)] (Ln = Gd 1, Dy 2; hfac = hexafluoroacetylacetonate; ImPhPyobis = 5-(4-oxypyridinium-1-yl)-1,3-bis(1'-oxyl-4',4',5',5'-tetramethyl-4,5-hydro-1-imidazol-2-yl)benzene) and [DyZn(hfac)(NITPhPyobis)] 3 (NITPhPyobis = 5-(4-oxypyridinium-1-yl)-1,3-bis(1'-oxyl-3'-oxido-4',4',5',5'-tetramethyl-4,5-hydro-1-imidazol-2-yl)benzene), have been successfully prepared. The three complexes possess {LnO} cores bridged by the oxygen atoms of the 4-oxypyridinium rings of the biradical ligands and one of the imino/nitronyl nitroxide groups of the biradical is coordinated to a Zn ion, then producing a centrosymmetric tetranuclear six-spin structure. The studies of spin dynamics indicate that complexes 2 and 3 exhibit distinct magnetic relaxation behaviors at zero dc field: complex 2 presents single relaxation with an effective energy barrier () of 69.8 K, while complex 3 exhibits double relaxation processes with values for the fast and slow relaxation being 15.8 K and 50.9 K, respectively. The observed different magnetic relaxation behaviors for the two Dy complexes could be mainly ascribed to the influence of the distinct nitroxide biradical derivatives.
通过使用硝酮/亚氨基氮氧双自由基，成功制备了三种镧系-锌配合物，即[LnZn(hfac)(ImPhPyobis)]（Ln = Gd 1，Dy 2；hfac = 六氟乙酰丙酮；ImPhPyobis = 5-(4-氧代吡啶-1-基)-1,3-双(1'-氧基-4',4',5',5'-四甲基-4,5-氢-1-咪唑-2-基)苯）和[DyZn(hfac)(NITPhPyobis)] 3（NITPhPyobis = 5-(4-氧代吡啶-1-基)-1,3-双(1'-氧基-3'-氧化-4',4',5',5'-四甲基-4,5-氢-1-咪唑-2-基)苯）。这三种配合物具有由双自由基配体的4-氧代吡啶环的氧原子桥连的{LnO}核，并且双自由基的一个亚氨基/硝酮氮氧基团与一个锌离子配位，从而产生中心对称的四核六自旋结构。自旋动力学研究表明，配合物2和3在零直流场下表现出不同的磁弛豫行为：配合物2呈现单一弛豫，有效能垒（）为69.8 K，而配合物3表现出双弛豫过程，快速和慢速弛豫的 值分别为15.8 K和50.9 K。观察到的两种镝配合物不同的磁弛豫行为主要可归因于不同的氮氧双自由基衍生物的影响。
