A series of custom-designed olefin-bridged bidentate adsorbates composed of an olefin group linking symmetrical hydrocarbon moieties of varying chain lengths was synthesized and used for the preparation of self-assembled monolayers (SAMs) on gold. The structures of the adsorbates are in the form Z-[CH₃(CH₂)_m]₂(C═C)[CH₂SH]₂ (OBCnSH) where m = 12–15 and n = m + 3 (OBC15SH, OBC16SH, OBC17SH, and OBC18SH). The influence of the olefin linker on the structural and interfacial properties of the SAMs was investigated and compared to SAMs formed from analogous n-alkanethiols. Characterization techniques included ellipsometry, X-ray photoelectron spectroscopy (XPS), polarization modulation-infrared reflection–adsorption spectroscopy (PM-IRRAS), and contact angle measurements. The OBCnSH SAMs exhibited ellipsometric thicknesses that were similar to their monodentate counterparts, suggesting that the new olefin-bridged adsorbates pack similarly to the monodentate analogs. Characterization by PM-IRRAS revealed that the OBCnSH SAMs were as conformationally ordered as those derived from the reference n-alkanethiols with the exception of the adsorbate with the shortest chain length OBC15SH, which exhibited low coverage and a liquid-like structure. Unlike the SAMs derived from the n-alkanethiols, the OBCnSH SAMs failed to exhibit “odd–even” effects. However, the OBCnSH SAMs displayed similar hexadecane contact angles as their n-alkanethiol counterparts with the exception of OBC15SH, which exhibited markedly diminished hexadecane contact angles. The similar structural and interfacial properties of the OBCnSH SAMs, when compared to analogous n-alkanethiol SAMs, render the molecular architecture of the olefin-bridged dithiol as a robust platform for the synthesis of adsorbates with two chemically distinct tailgroups for use in the preparation and study of phase-incompatible “conflicted” interfaces.

中文翻译：

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烯烃桥接双齿吸附剂，用于在金上生成自组装单层膜。

合成了一系列定制设计的烯烃桥联双齿吸附物，该吸附剂由连接不同链长的对称烃部分的烯烃基团组成，并用于在金上制备自组装单分子膜（SAMs）。吸附物的结构为Z- [CH ₃（CH ₂）_m ] ₂（C═C）[CH ₂ SH] ₂（OBC n SH）形式，其中m = 12–15和n = m + 3（OBC15SH，OBC16SH，OBC17SH和OBC18SH）。研究了烯烃接头对SAM的结构和界面性能的影响，并将其与由类似的正烷硫醇形成的SAM进行了比较。表征技术包括椭圆偏振法，X射线光电子能谱（XPS），偏振调制-红外反射-吸收光谱（PM-IRRAS）和接触角测量。的OBC Ñ SH的SAM表现出其类似于他们的单齿对应椭偏厚度，这表明新烯烃桥接吸附同样包装到单齿的类似物。PM-IRRAS的表征表明，OBC n SH SAMs的构象与从参考n衍生的构象有序-链烷硫醇，但链长最短的被吸附物OBC15SH除外，它的覆盖率低且呈液体状。与衍生自正烷硫醇的SAM不同，OBC n SH SAM未能表现出“奇偶”效应。但是，除OBC15SH以外，OBC n SH SAMs的正十六烷接触角与它们的正链烷硫醇对应物相似，十六烷接触角显着减小。与类似的n相比，OBC n SH SAM的结构和界面性质相似-链烷硫醇SAMs使烯烃桥联的二硫醇的分子结构成为合成具有两个化学上不同的尾基的吸附物的强大平台，用于制备和研究相不相容的“冲突”界面。