含酰胺结构的巯基自组装膜的设计与结构表征

New Approach on the Synthesis of Functionalized Alkanethiols and the Structural Characterization of Their Self-Assembled Monolayers

提出了一种简便通用的合成巯基化合物的途径，以分子中的羧基CO2H为起始基团，与2-流基乙胺的氨基选择性缩合；合成了一系列具有RC（O）NHCH2CH2SH（R分别为偶氯苯衍生物，双炔衍生物及直链烷基）结构的化合物，并用接触角测量，电化学和掠角反射红外光谱（GIR-IR）等手段对这些化合物在金表面形成的自组装单分子膜进行了表征。发现4-（N－（2‘-巯基已基））酰胺偶氮苯的自组装膜表现出良好的电活性，电化学测定表面浓度为4．21×10(－10)mol·cm(-2)．当R为烷基链时，随烷基链的增长，膜的致密度与有序度增加GIR-IR证明在自组装腹中CH3（CH2）6C（O）NHCH2CH2SH的C＝O和N－H键与Au表面平行，分子轴线与Au表面近似垂直．

A simple and general method for synthesizing functionalized alkanethiols is reported.The synthesis started from carboxylic acid, RCOOH, which was selectively condensed with the armno group of 2-andnoethanethiol, thus giving the targetting thiol compounds- A series of thiol compounds having a structure of RC(O)NHCH2CH2SH, where R was azobenzene derivatives,dicetylene derivatives and n-akanes, respectively, have been synthesized using this method. The self-assembled monolayers(SAMs) of these species were characterized by wettability measurement,electrochemistry and grazing incidence refletance infrared spectroscopy(GIRIR). The SAM from 4((N-(2-mercaptrvethyl)amino)ca azobenzene showed clearcut electrochemical reactivity in aqueous solution, in which the surface coverage was evaluated to be 4.21×10-10mol'cm-2. On the other hand, for the thiols of R being n-alkanes, the packing structures became gradually im-proved with increasing the alkyl chain length. For CH3(CH2)6C(O)NHCH2CH2SH SAM, GIR-IR data indicate that the C=0 and N-H groups are parallel with the substrate surface while the whole molecular axis is perpendicular to the surface.