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96 results on '"Aloisi, Gian Gaetano"'

3. Comprehensive investigation of photophysical behavior of oligopolyfurans

Author

Melo, J. Seixas de, Elisei, Fausto, Aloisi, Gian Gaetano, Becker, Ralph S., and Gartner, Carlos

Subjects
Fluorescence -- Analysis, Excited state chemistry -- Research, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

An examination is done on the photophysical properties of (oligo)polyfurans. It is found that it is not possible to clearly distinguish whether cis and trans conformers simultaneously exist (most likely for F2), or the magnitude of inter-ring bond twisting but the latter appears to be no more than 20--30 degrees and the virtual molecules at 77 K are clearly more planar than at room temperature.

Published
2000

8. Una fonte di energia e di informazione

Author

Aloisi, Gian Gaetano, Barbafina, Arianna, Elisei, Fausto, Favaro, Giovanna, Gentili, Pier Luigi, Latterini, Loredana, Masetti, Fausto, Mazzucato, Ugo, Ortica, Fausto, Romani, Aldo, and Spalletti, Anna

Published
2008

43. Preparation and characterization of zirconium phosphonate–azobenzene intercalation compounds. A structural, photophysical and photochemical study

Author

Gentili, Pier Luigi, Costantino, Umberto, Vivani, Riccardo, Latterini, Loredana, Nocchetti, Morena, and Aloisi, Gian Gaetano

Abstract

The physical and chemical photo-responses of azobenzene were employed to investigate the ‘nanoscopic’ properties of a layered zirconium phosphonate of formula ZrF(O3PCH2)2NHC8H17 (ZrC8, interlayer distance 1.82 nm), a solid belonging to a new family of zirconium diphosphonates with a poorly hindered interlayer region. Two samples were prepared: an intercalation compound containing 0.8 mol of dye per mol of zirconium, having an interlayer distance of 2.82 nm; and a compound in which the azobenzene was adsorbed on the surface of the host. The photobehaviour of the samples was examined by absorption, fluorescence and photochemical techniques and compared with those of the dye in the solid state and in solution. Intercalated or adsorbed azobenzene is able to fluoresce not only from the lowest excited singlet state 1(n,π*) but also from the upper one 1(π,π*), as observed in the solid dye. However, differently from what happens in the pure solid dye, the trans→cis photoisomerization of azo-groups occurred in both intercalated and adsorbed samples upon UV irradiation. The structural changes associated with the photoisomerization process in the interlamellar region induced an irreversible deintercalation of the dye, which was detected as adsorbed on the host surface or present in an amorphous phase. Space-resolved properties of the ZrC8–azobenzene materials were investigated by confocal fluorescence microscopy.

Published
2004

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