An X-Ray Diffraction Study on the Structures of Bis- and Tris(ethylenediamine)nickel(II) Complexes in Solution
作者:Tadao Fujita、Hitoshi Ohtaki
DOI:10.1246/bcsj.55.455
日期:1982.2
The structures of nickel(II) complexes with ethylenediamine(en) in solution have been determined by means of X-ray diffraction. The measurements were performed at 25 °C for aqueous ethylenediamine solutions of nickel nitrate, the mole ratios (en/Ni) in the solutions being 3.964, 3.672, 2.071, and 1.892. In the two solutions of the higher en/Ni mole ratio, the tris(ethylenediamine)nickel(II) complex was predominant, whereas in the other solutions the bis(ethylenediamine)nickel(II) complex was contained as the main species. From the analysis of the X-ray scattering data of the solutions, it was shown that in the bis-complex four nitrogen atoms within ethylenediamine and two oxygen atoms within water molecules were octahedrally coordinated to the central nickel(II) atom, the oxygen atoms being assumed to be axially bonded. The Ni–N bond length within the bis-complex was 2.10 Å, which was almost the same as the length of the Ni–O bonds. The nonbonding Ni···C distance was 2.82(2) Å. In the tris-complex the nickel ion was coordinated with six nitrogen atoms and Ni–N and Ni···C distances were determined to be 2.202(4) Å and 2.88(1) Å, respectively. These parameter values obtained in the experiment were compared with the crystallographic data reported.
通过 X 射线衍射法测定了镍 (II) 与乙二胺 (en) 在溶液中的配合物结构。测量是在 25 °C 下对硝酸镍的乙二胺水溶液进行的,溶液中的分子比(en/Ni)分别为 3.964、3.672、2.071 和 1.892。在烯/镍摩尔比较高的两种溶液中,主要是三(乙二胺)镍(II)络合物,而在其他溶液中,主要是双(乙二胺)镍(II)络合物。对溶液 X 射线散射数据的分析表明,在双络合物中,乙二胺中的四个氮原子和水分子中的两个氧原子与中心镍(II)原子呈八面体配位,氧原子被假定为轴键。双复合物中 Ni-N 键的长度为 2.10 Å,几乎与 Ni-O 键的长度相同。在三元复合物中,镍离子与六个氮原子配位,Ni-N 和 Ni-C 的距离分别为 2.202(4) Å 和 2.88(1) Å。实验中获得的这些参数值与所报告的晶体学数据进行了比较。