Su Qian-Qian, Fan Kun, Huang Xin-Da, Xiang Jing, Cheng Shun-Cheung, Ko Chi-Chiu, Zheng Li-Min, Kurmoo Mohamedally, Lau Tai-Chu
College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, Hubei, P. R. China.
State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Dalton Trans. 2020 Apr 1;49(13):4084-4092. doi: 10.1039/d0dt00295j.
Photochemical reactions of (PPh4)[OsVI(N)(L)(CN)3] (NO2-OsN) with piperidine and pyrrolidine afforded two osmium(v) hydrazido compounds, (PPh4)[OsV(L)(CN)3(NNC5H10)] ([PPh4]1) and (PPh4)[OsV(L)(CN)3(NNC4H8)] ([PPh4]2), respectively. Their structures consist of isolated, mononuclear distorted octahedral osmium anions that are well-separated from each other by PPh4+. Their low spin S = 1/2 and L = 1 ground state was confirmed by magnetometry and DFT calculations. Interestingly, both compounds exhibit slow magnetic relaxation under a bias dc-field. These osmium(v) complexes are potentially useful building-blocks for the construction of molecule-based architectures with interesting magnetic properties. In contrast, the structurally related (PPh4)[OsIII(L)(CN)3(NH3)] ([PPh4]3), which also has a low-spin S = 1/2 ground state but with a different electronic configuration (5d5), does not exhibit slow magnetic relaxation, due to the absence of any orbital moment (L = 0). Furthermore, the structurally different osmium(v) hydrazido compound reported by Meyer, OsV(tpy)(Cl)2(NNC5H10) (4[PF6]), also does not exhibit slow magnetic relaxation due possibly to a change in magnetic anisotropy from axial for [PPh4]1 and [PPh4]2 to planar.
(PPh4)[OsVI(N)(L)(CN)3]（NO2-OsN）与哌啶和吡咯烷的光化学反应分别生成了两种锇（V）酰肼化合物，即(PPh4)[OsV(L)(CN)3(NNC5H10)]（[PPh4]1）和(PPh4)[OsV(L)(CN)3(NNC4H8)]（[PPh4]2）。它们的结构由孤立的单核扭曲八面体锇阴离子组成，这些阴离子通过PPh4+彼此很好地分离。通过磁力测量和DFT计算证实了它们的低自旋S = 1/2和L = 1基态。有趣的是，这两种化合物在偏置直流场下均表现出缓慢的磁弛豫。这些锇（V）配合物可能是构建具有有趣磁性的分子基结构的有用构建块。相比之下，结构相关的(PPh4)[OsIII(L)(CN)3(NH3)]（[PPh4]3），其也具有低自旋S = 1/2基态但具有不同的电子构型（5d5），由于不存在任何轨道矩（L = 0），不表现出缓慢的磁弛豫。此外，Meyer报道的结构不同的锇（V）酰肼化合物OsV(tpy)(Cl)2(NNC5H10)（4[PF6]）也不表现出缓慢的磁弛豫，这可能是由于磁各向异性从[PPh4]1和[PPh4]2的轴向变为平面。
