The crystal and molecular structure of the title complex has been determined by X-ray diffraction using 1882 reflections. The crystal was orthorhombic, with the space group Pbn21; a=10.98(2), b=18.496(4), c=7.341(9), Z=4, Dx=1.99, Dm=1.98(2) g cm−3,μ(Mo Kα)=19.3 cm−1, and the final R value was 0.036. A distorted ψ-pentagonal bipyramid is formed around the central antimony(III) atom by two nitrogen and two oxygen atoms, together with a lone electron pair at the equatorial positions and two oxygen atoms at the axial positions. One of the Sb–O distances, 2.78 Å, is longer than the others (2.20(2) Å on the average), and it is determined that the carbonyl oxygen is essentially of the free-acid type and that its carbonyl oxygen is weakly coordinated. The splitting of the νas(COO) band of its infrared and Raman spectra shows the existence of both free and coordinated carboxyl groups. The 1H- and 13C-NMR results show that the antimony(III)–edta complex does not exchange with the free ligand in an aqueous solution at pH 1.5–3.5.
通过 X 射线衍射,利用 1882 次反射,确定了标题配合物的晶体和分子结构。晶体呈正方晶形,空间群为 Pbn21;a=10.98(2),b=18.496(4),c=7.341(9),Z=4,Dx=1.99,Dm=1.98(2) g cm-3,μ(Mo Kα)=19.3 cm-1,最终 R 值为 0.036。在中心
锑(III)原子周围,由两个氮原子和两个氧原子以及位于赤道位置的一个孤电子对和位于轴向位置的两个氧原子形成了一个扭曲的ψ-五边形双锥体。其中一个 Sb-O 间距为 2.78 Å,比其他间距要长(平均为 2.20(2) Å),因此可以确定羰基氧基本上属于
游离酸类型,其羰基氧为弱配位。其红外光谱和拉曼光谱中的νas(COO)波段的分裂显示了游离和配位羧基的存在。1H- 和 13C-NMR 结果表明,
锑(III)-edta 复合物在 pH 值为 1.5-3.5 的
水溶液中不会与游离
配体发生交换。