Ethambutol (as its dihydrochloride) is a bacteriostatic drug, which is widely used as part of the Tuberculosis treatment protocol. It can also act as a ligand for various metal ions, such as copper(II), leading to complexes with potentially interesting applications in medicinal and analytical chemistry. The structure of such complexes is relevant to the question of the coordination geometry of the copper(II) ion in aqueous solution. We report a structural study of the 1:1 complex formed between ethambutol (Emb) and copper(II), using visible absorption, multinuclear NMR (¹H and ¹³C), and EPR spectroscopies, and density functional theory (DFT) calculations. These all support a pentacoordinate structure with a distorted square pyramidal geometry involving a central Cu(II) ion coordinated by a tetradentate Emb ligand and one water molecule. The diffusion behaviour of this complex has been studied, and is compared with that of the free ligand by measuring limiting mutual diffusion coefficients for aqueous systems at 25 °C using the Taylor dispersion method. From these results, we have estimated the tracer diffusion coefficient of ethambutol in supporting solutions of copper nitrate and the limiting diffusion coefficients of the 1:1 complex formed between ethambutol and copper ion. By using the Stokes-Einstein equation, the limiting hydrodynamic radii of this complex, R_h, have also been estimated and are compared with the free Emb.

乙胺丁醇（作为其二盐酸盐）是一种抑菌药物，被广泛用作结核病治疗方案的一部分。它也可以充当各种金属离子（如铜（II））的配体，从而导致在医学和分析化学领域具有潜在意义的复合物。这种络合物的结构与水溶液中铜（II）离子配位几何形状的问题有关。我们报告了使用可见吸收，多核NMR（¹ H和¹³）在乙胺丁醇（Emb）和铜（II）之间形成的1：1配合物的结构研究C），EPR光谱和密度泛函理论（DFT）计算。这些都支持具有扭曲的方形锥体几何结构的五坐标结构，该结构包括由四齿Emb配体和一个水分子配位的中心Cu（II）离子。已经研究了该络合物的扩散行为，并通过使用泰勒分散法测量水性体系在25°C下的极限相互扩散系数，将其与游离配体的扩散行为进行了比较。根据这些结果，我们估算了乙胺丁醇在硝酸铜支持溶液中的示踪剂扩散系数以及乙胺丁醇与铜离子之间形成的1：1配合物的极限扩散系数。通过使用Stokes-Einstein方程，该复合体的极限流体力学半径R _h，也已估算并与免费的Emb进行了比较。