Cavitand-Functionalized Porous Silicon as an Active Surface for Organophosphorus Vapor Detection

详细信息    查看全文

• 作者：Cristina Tudisco ; Paolo Betti ; Alessandro Motta ; Roberta Pinalli ; Luigi Bombaci ; Enrico Dalcanale ; Guglielmo G. Condorelli
• 刊名：Langmuir
• 出版年：2012
• 出版时间：January 24, 2012
• 年：2012
• 卷：28
• 期：3
• 页码：1782-1789
• 全文大小：470K
• 年卷期：v.28,no.3(January 24, 2012)
• ISSN：1520-5827

文摘

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鈥揼uest interactions of the PSi-bonded receptors, and the reversibility of the guest complexation.