Evidence for Reagent-Induced Spin-State Switching in Tripodal Fe(II) Iminopyridine Complexes
Evidence for Reagent-Induced Spin-State Switching in Tripodal Fe(II) Iminopyridine Complexes
复制标题
三足 Fe(II) 亚氨基吡啶配合物中试剂诱导自旋态转换的证据
DOI：
10.1021/acs.inorgchem.9b00340
复制
发表时间：
2019
影响因子：
4.6
通讯作者：
Shores, Matthew P.
中科院分区：
文献类型：
--
作者：
Ozumerzifon, Tarik J.;Higgins, Robert F.;Joyce, Justin P.;Kolanowski, Jacek L.;Rappé, Anthony K.;Shores, Matthew P.
我们提出了两个相关的Fe(II)亚氨基吡啶配位络合物上伴随着脱硅反应的自旋态变化的证据。为了探索这些体系，我们用溶液中的CSF进行滴定，并用原位磁测量、电化学和质谱学技术分析了它们的形态。我们发现，在这些条件下，侧链叔丁基二甲基硅基很容易被裂解，由此得到的脱硅络合物的溶液磁化率值总体上降低。密度泛函理论和从头计算探讨了取代基同一性(脱硅前后)对金属配体σ给体和π受体成键性质的影响。我们将观察到的自旋态变化归因于与硅化的高自旋络合物的构象自由相关的熵的减少，导致在脱硅时更有利于低自旋态。
We present evidence of a spin-state change that accompanies desilylation reactions performed on two related Fe(II) iminopyridine coordination complexes. To probe these systems, we performed titrations with CsF in solution and analyzed the speciation with in situ magnetometry, electrochemistry, and mass spectrometry techniques. We find that pendanttert-butyldimethylsilyl groups are readily cleaved under these conditions, and the resulting desilylated complexes exhibit overall decreased solution magnetic susceptibility values. Density functional theory andab initiocomputations probe the impact of substituent identity (prior to- and post-desilylation) on the metal–ligand σ-donor and π-acceptor bonding properties. We attribute the observed spin-state changes to the decrease in entropy associated with the conformational freedom of the silylated high-spin complex, resulting in a more favored low-spin state upon desilylation.