Two new air-stable mononuclear pentacoordinate CoII complexes [Co(bpip)(NCS)2] (1) and [Co(bpip)Br2] (2), which are based on a NNN-pincer ligand 2,6-bis(imidazo[1,5-a]pyridin-3-yl)pyridine (abbreviated as bpip), were successfully synthesized and structurally characterized. Although two different halogen and pseudohalogen terminal ligands were employed, single-crystal X-ray crystallographic analyses revealed that the CoII center of 1 and 2 adopts C4v symmetry and displays the similar distorted square-pyramidal geometry. Magnetic studies showed that two compounds exhibit slow magnetic relaxation in the presence of an applied dc field, namely, they display the behavior of single-ion magnets (SIMs). The reported two complexes enrich the chemistry of cobalt(II) single-ion magnets (SIMs) with low coordination numbers and highlight the differences in the magnetic behaviors caused by the different terminal ligands.

中文翻译：

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具有钳形配体 2,6-双(咪唑并[1,5-a] 吡啶-3-基)吡啶的两个五配位 CoII 配合物的单离子磁体行为

两种新的空气稳定单核五配位 CoII 配合物 [Co(bpip)(NCS)2] (1) 和 [Co(bpip)Br2] (2)，它们基于 NNN 钳状配体 2,6-双（咪唑并） [1,5-a]pyridin-3-yl)pyridine (缩写为 bpip) 被成功合成和结构表征。尽管使用了两种不同的卤素和拟卤素末端配体，单晶 X 射线晶体学分析表明，1 和 2 的 CoII 中心采用 C4v 对称性，并显示出类似的扭曲方形锥体几何形状。磁性研究表明，两种化合物在施加直流场的情况下表现出缓慢的磁弛豫，即它们表现出单离子磁铁 (SIM) 的行为。