Campanella Anthony J, Ozvat Tyler M, Zadrozny Joseph M
Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA.
Dalton Trans. 2022 Feb 22;51(8):3341-3348. doi: 10.1039/d1dt02156g.
Complexes of encapsulated metal ions are promising potential metal-based electron paramagnetic resonance imaging (EPRI) agents due to zero-field splitting. Herein, we synthesize and magnetically characterize a series of five new Ni(II) complexes based on a clathrochelate ligand to provide a new design strategy for zero-field splitting in an encaged environment. UV-Vis and X-ray single-crystal diffraction experiments demonstrate slight physical and electronic structure changes as a function of the differing substituents. The consequence of these changes at the remote apical and sidearm positions of the encaging ligands is a zero-field splitting parameter () that varies over a large range of 11 cm. These results demonstrate a remarkable flexibility of the zero-field splitting and electronic structure in nickelous cages and give a clear toolkit for modifying zero-field splitting in highly stable ligand shells.
由于零场分裂，封装金属离子的配合物是很有前景的潜在金属基电子顺磁共振成像（EPRI）剂。在此，我们基于一种笼形螯合物配体合成并对一系列五个新的Ni(II)配合物进行了磁性表征，以提供一种在笼状环境中实现零场分裂的新设计策略。紫外可见光谱和X射线单晶衍射实验表明，随着取代基的不同，物理和电子结构会发生轻微变化。在笼形配体的远端顶端和侧臂位置发生的这些变化的结果是，零场分裂参数（）在11 cm的大范围内变化。这些结果证明了镍笼中零场分裂和电子结构具有显著的灵活性，并为在高度稳定的配体壳中调节零场分裂提供了一个清晰的工具包。
