Otón Francisco, Tárraga Alberto, Espinosa Arturo, Velasco María D, Molina Pedro
Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, E-30100 Murcia, Spain.
Dalton Trans. 2006 Aug 14(30):3685-92. doi: 10.1039/b603544b. Epub 2006 May 30.
The synthesis of structurally new types of ferrocene-based ureas, in which the ferrocene moiety is simultaneously attached to two urea groups, have been prepared directly from 1,1-bis(isocyanato)ferrocene 1. Receptors 2a, 2b, and 2d show spectral and electrochemical anion-sensing capability for hydrogenphosphate and fluoride anions, in addition 2d also shows a sensing capability for acetate anion. Heteroditopic receptor 2a, bearing a pyridine binding site, does not complex Cu2+ cations but instead an intramolecular redox reaction takes place to give the oxidized form 2a+. The results obtained by using the heteroditopic receptor 2b, containing two crown ethers units, demonstrate that K+ cations can only be electrochemically detected in the presence of hydrogenphosphate anion. Whereas the new structural motif 2d, in which the two urea groups are part of the macrocycle framework, is a selective electrochemical sensor for Li+ cation in the presence of alkali metal ions. The preferred binding modes and their extent are proposed for the most representative complexes by means of DFT-based theoretical calculations.
已直接由1,1-双（异氰酸根合）二茂铁1制备了结构新型的二茂铁基脲的合成物，其中二茂铁部分同时连接到两个脲基团上。受体2a、2b和2d对磷酸氢根和氟离子显示出光谱和电化学阴离子传感能力，此外，2d对醋酸根阴离子也显示出传感能力。带有吡啶结合位点的异双功能受体2a不与Cu2+阳离子络合，而是发生分子内氧化还原反应生成氧化形式2a+。使用含有两个冠醚单元的异双功能受体2b获得的结果表明，只有在磷酸氢根阴离子存在下才能电化学检测到K+阳离子。而新的结构基序2d，其中两个脲基团是大环框架的一部分，是在碱金属离子存在下对Li+阳离子的选择性电化学传感器。通过基于密度泛函理论的计算，为最具代表性的配合物提出了优选的结合模式及其程度。
