title: Cavitand-functionalized porous silicon as an active surface for organophosphorus vapor detection.
abstract: 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.
authors.affiliation: Dipartimento di Scienze Chimiche, Università di Catania and INSTM UdR di Catania, v.le A. Doria 6, 95125 Catania, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Tudisco
authors.forename: Paolo
authors.initials: P
authors.lastname: Betti
authors.forename: Alessandro
authors.initials: A
authors.lastname: Motta
authors.forename: Roberta
authors.initials: R
authors.lastname: Pinalli
authors.forename: Luigi
authors.initials: L
authors.lastname: Bombaci
authors.forename: Enrico
authors.initials: E
authors.lastname: Dalcanale
authors.forename: Guglielmo G
authors.initials: GG
authors.lastname: Condorelli
mesh_terms: D004988:Ethers, Cyclic / Q000138:chemical synthesis / Q000737:chemistry*; D005740:Gases / Q000032:analysis*; D013058:Mass Spectrometry; D008956:Models, Chemical; D009943:Organophosphorus Compounds / Q000032:analysis* / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D016062:Porosity; D012118:Resorcinols / Q000138:chemical synthesis / Q000737:chemistry*; D012524:Sarin / Q000737:chemistry; D012825:Silicon / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D004988:Ethers, Cyclic; D005740:Gases; D009943:Organophosphorus Compounds; D012118:Resorcinols; C442939:cavitand; C031116:dimethyl methylphosphonate; D012524:Sarin; D012825:Silicon