A {Co<sup>III</sup><sub>2</sub>Dy<sup>III</sup><sub>4</sub>} Single-Molecule Magnet with an Expanded Core Structure
作者:Dumitru Stati、Jan van Leusen、Naushad Ahmed、Victor Ch. Kravtsov、Paul Kögerler、Svetlana G. Baca
DOI:10.1021/acs.cgd.2c01085
日期:2023.1.4
The coordination cluster compound [CoIII2DyIII4(OH)2(ib)8(bdea)2(NO3)4(H2O)2]·2MeCN (1) self-assembles in a high-yield reaction of cobalt(II) isobutyrate (ib) with Dy(NO3)3·6H2O and N-butyldiethanolamine (H2bdea) in air. The Ci-symmetric CoIII2DyIII4} core fragment features two CoDy2(μ3-OH)} triangles, joined by one of their Dy sites via μ-O and μ-carboxylate bridges. This results in a flat zigzag metal skeleton, in contrast to previously reported hexanuclear Co2Ln4(μ3-OH)2} clusters, namely, exhibiting a more condensed combination of two CoLn2(μ3-OH)} triangles that form a Dy4 rhombus. According to ac susceptibility measurements, this rearrangement in 1 reduces quantum tunneling of the magnetization and hence pushes up the onset of pronounced out-of-phase signals at zero bias field to 14 K, a significant change vs the more condensed Co2Dy4} structures. As intermolecular interactions between coordination clusters in the solid state are well-known to also influence SMM features, comparative Hirshfeld surface analyses are also presented.
异丁酸钴(II)(ib)与 Dy(NO3)3-6H2O 和 N-丁基二乙醇胺(H2bdea)在空气中发生高产反应,自组装出配位簇化合物 [CoIII2DyIII4(OH)2(ib)8(bdea)2(NO3)4(H2O)2]-2MeCN (1)。Ci 对称的CoIII2DyIII4}核心片段具有两个CoDy2(μ3-OH)}三角形,其中一个 Dy 位点通过μ-O 和μ-羧酸桥连接起来。这就形成了一个扁平的 "之 "字形金属骨架,与之前报道的六核Co2Ln4(μ3-OH)2}团簇形成鲜明对比,后者表现出两个CoLn2(μ3-OH)}三角形的更紧密结合,形成了一个 Dy4 菱形。根据交流电感测量结果,1 中的这种重新排列减少了磁化的量子隧穿,从而将零偏置磁场下明显的失相信号的发生时间提前到 14 K,这与更为凝聚的 Co2Dy4} 结构相比是一个显著的变化。众所周知,固态配位团簇之间的分子间相互作用也会影响 SMM 特征,因此还介绍了 Hirshfeld 表面比较分析。