Electrografting of Mono-N-Boc-Ethylenediamine from an Acetonitrile/Aqueous NaHCO3 Mixture

碳电极表面的伯胺电嫁接被广泛地应用于电极表面改性. 本文通过比较发现，在比例为4:1的乙腈和0.1 mol•L-1 碳酸氢钠溶液混合物中，玻碳电极表面嫁接上叔丁氧羟基-乙二胺的效率比在单纯的乙腈中显著提高. 有碳氢酸钠存在时，循环伏安测得电极的初始电流增大，表明电极表面胺嫁接层的形成更快速，从而使得电极表面更容易钝化，导致乙二胺-叔丁氧羟基膜层更严重地阻碍[Fe(CN)6]3-. 的反应. 通过去除叔丁氧羟基保护层，在蒽醌-2-羧酸上接自由胺，可获得较高的蒽醌表面覆盖度. 采用简单动力学模型模拟了电嫁接反应，结果表明，模拟得到的循环伏安曲线与实验测得的循环伏安曲线相一致. 对比在单纯乙腈和乙腈/碳酸氢钠溶液混合物中模型拟合得到的参数值可知，胺自由基与碳表面的反应和在均相溶液中的反应相互竞争，更有利于乙腈与碳氢酸钠的表面反应.The electrografting of primary amines to carbon electrodes is now widely employed for electrode modification. Using a mixture of acetonitrile and 0.1 mol•L-1 aqueous sodium hydrogen carborate (NaHCO3) in the ratio of 4:1, the efficiency for coupling of mono-N-Boc-ethylenediamine (EDA-Boc) on the surface of glassy carbon was significantly improved as compared with that obtained using acetonitrile alone. In the presence of NaHCO3 the initial current determined in the cyclic voltammogram became higher, and the layer of attached amine was formed more rapidly, accordingly, the electrode was passivated more rapidly. The resulting film of EDA-Boc was shown to be more severely blocking toward the electrochemical reaction of [Fe(CN)6]3-. Following removal of the Boc protecting group and coupling of the free amine to anthraquinone-2-carboxylic acid, a higher surface coverage of the anthraquinone was obtained. Modelling for the electrograftng reaction using a simple kinetic scheme, it was demonstrated that the simulated voltammograms agreed well with the experimentally measured voltammograms . Comparison between the model fitting parameters obtained from the acetonitrile alone and the acetonitrile/NaHCO3 mixture showed that the competition between reaction of the amine radicals with the carbon surface and reaction in the homogeneous solution became more favourable for the surface reaction in the acetonitrile/NaHCO3 mixture.H. Hamzah would like to thank the Majlis Amanah Rakyat Malaysia (MARA) for the PhD scholarship. P. Bartlett gratefully acknowledges receipt of a Wolfson Research Merit award.H. Hamzah would like to thank the Majlis Amanah Rakyat Malaysia (MARA) for the PhD scholarship. P. Bartlett gratefully acknowledges receipt of a Wolfson Research Merit award.作者联系地址：1. 南安普顿大学化学系，英国南安普顿，SO17 1AL；2. 伦敦大学玛丽女王学院，生物与化学科学学院，英国伦敦，E1 4NS；3. 阿伯丁大学国王学院，英国阿伯丁，AB24 3FXAuthor's Address: 1. Chemistry, University of Southampton, Southampton, SO171AL, UK; 2. School of Biological and Chemical Sciences Queen Mary University of London, Mile End Road, London, E1 4NS, UK; 3. King’s College, The University of Aberdeen, Aberdeen, AB24 3FX, UK通讯作者E-mail：p.n.bartlett@soton.ac.u