Kinetics and Mechanism of Ligand Interchange in Pentacyano-L-osmate(II) Complexes (L = H<sub>2</sub>O, NH<sub>3</sub>, N-Heterocyclic Ligands)
作者:Leonardo D. Slep、Pablo Alborés、Luis M. Baraldo、José A. Olabe
DOI:10.1021/ic010923a
日期:2002.1.1
The new complex, K(3)[Os(CN)(5)NH(3)].2H(2)O, a convenient precursor for the pentacyano-L-osmate(II) series, was prepared and characterized by chemical analysis, cyclic voltammetry, and IR and UV-vis spectroscopies. By controlled aquation in weakly acidic medium, the [Os(CN)(5)H(2)O](3-) ion was generated. Weak absorptions in the UV region for L = H(2)O, NH(3), and CN(-) were found at 287, 272, and
制备了新的配合物K(3)[Os(CN)(5)NH(3)]。2H(2)O,该化合物是戊酰基-L-osmate(II)系列的便捷前体,并通过化学分析进行了表征,循环伏安法以及红外和紫外可见光谱。通过在弱酸性介质中控制水合,生成了[Os(CN)(5)H(2)O](3-)离子。L = H(2)O,NH(3)和CN(-)在UV区的弱吸收分别在287、272和240 nm处发现,并根据模型分配给dd跃迁四方畸变离子也适用于铁和钌系列的成员。[Os(CN)(5)L](n-)离子的形成和离解反应的动力学,L =吡啶(py),吡嗪(pz),N-甲基吡嗪鎓(mpz(+))等。 ,进行了研究。在25.0摄氏度下,中性配体pz和异烟酰胺的形成速率常数约为。0。13 M(-1)s(-1),对于L = mpz(+)略有增加,对于异烟酸酯减少。活化焓为约。大约22.0 kcal mol(-1),与进入的L无关,并且激活熵均为正。11-13