Dipartimento di Scienze Chimiche, Università di Catania and INSTM UdR di Catania, v.le A. Doria 6, 95125 Catania, Italy.
Langmuir. 2012 Jan 24;28(3):1782-9. doi: 10.1021/la203797b. Epub 2012 Jan 12.
This paper reports on the preparation of a porous silicon-based material covalently functionalized with cavitand receptors suited for the detection of organophosphorus vapors. Two different isomeric cavitands, both containing one acid group at the upper rim, specifically designed for covalent anchoring on silicon, were grafted on H-terminated porous silicon (PSi) by thermal hydrosilylation. The covalently functionalized surfaces and their complexation properties were characterized by combining different analytical techniques, namely X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and mass spectroscopy analysis coupled with thermal desorption experiments. Complexation experiments were performed by exposing both active surfaces and a control surface consisting of PSi functionalized with a structurally similar but inactive methylene-bridged cavitand (MeCav) to dimethyl methylphosphonate (DMMP) vapors. Comparison between active and inactive surfaces demonstrated the recognition properties of the new surfaces. Finally, the nature of the involved interactions, the energetic differences between active and inactive surfaces toward DMMP complexation, and the comparison with a true nerve gas agent (sarin) were studied by DFT modeling. The results revealed the successful grafting reaction, the specific host-guest interactions of the PSi-bonded receptors, and the reversibility of the guest complexation.
本文报道了一种多孔硅基材料的制备，该材料通过共价键功能化接枝了具有主体空腔受体的化合物，可用于检测有机磷蒸气。两种不同的异构体空腔受体，都在上边缘含有一个酸性基团，专门设计用于在硅上进行共价锚定，通过热硅氢化反应接枝到 H 终止的多孔硅（PSi）上。通过结合不同的分析技术，即 X 射线光电子能谱（XPS）、傅里叶变换红外光谱（FTIR）和质量光谱分析以及热脱附实验，对共价功能化表面及其络合性能进行了表征。通过将两个活性表面和一个由结构相似但无活性的亚甲基桥接空腔（MeCav）官能化的 PSi 组成的对照表面暴露于二甲基甲基膦酸酯（DMMP）蒸气中，进行了络合实验。活性表面和非活性表面之间的比较证明了新表面的识别性能。最后，通过 DFT 建模研究了涉及的相互作用的性质、活性和非活性表面与 DMMP 络合的能量差异以及与真正的神经毒气剂（沙林）的比较。结果表明成功地进行了接枝反应，PSi 键合受体的特异性主客体相互作用，以及客体络合的可逆性。
