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110 results on '"VITERBO D"'

6. Single-crystal synchrotron radiation x-ray diffraction study of B and Ga silicates compared to a purely siliceous MFI: a discussion of the heteroatom distribution

Author

Palin, L., Lamberti, C., Kvick, A., Testa, F., Aiello, R., Milanesio, M., and Viterbo, D.

Subjects
Silicates -- Structure, Gallium -- Structure, Boron -- Structure, Chemicals, plastics and rubber industries
Abstract

The structure determinations, obtained by synchrotron radiation single-crystal x-ray diffraction experiments, of as-synthesized orthorhombic MFI boron and gallium silicates compared to that of an unsubstantiated defect-free silicatite was reported. The absence of any measurable signal due to Si (OH) species in the (super 29) Si NMR spectra of silicalite indicates that their defectivity is very low because the samples are almost free of Si vacancies which are usually rather common in MFI materials.

Published
2003

7. Iron location in Fe-silicalites by synchroton radiation single crystal X-ray D Diffraction

Author

Milanesio, M., Lamberti, C., Aiello, R., Testa, F., Piana, M., and Viterbo, D.

Subjects
Iron -- Research, Chemicals, plastics and rubber industries
Abstract

The structural evidence, obtained by synchrotron radiation single-crystal X-ray diffraction experiments, of the presence of preferential substitution sites for iron heteroatoms hosted in the MFI framework of a Na-Fe-silicalite sample is presented. Independent data obtained on single crystals of Fe-silicalite samples synthesized with NH(sub 4)+ and K+ counterions and those obtained on the sodium derivative are found to correlate.

Published
2000

14. Structural Characterisation of Metabolites from Pholiota spumosa (Basidiomycetes)

Author

Clericuzio, M., Piovano, M., Chamy, M. C., Garbarino, J. A., Milanesio, M., Viterbo, D., Giovanni Vidari, and Finzi, P. V.

Subjects
Pholiota spumosa, Strophariaceae, fungi, terpenes, cinnamic acid amides, X-ray crystal structure
Abstract

Three compounds of different biosynthetic origin were isolated from the fruiting bodies of the gilled mushroom Pholiota spumosa (Basidiomycetes, Strophariaceae). Fasciculol E, a lanostane triterpenoid conjugated to a depsipeptide unit, was isolated for the first time from genus Pholiota. In addition, the first isolation of putrescine-1,4-dicinnamamide as a natural compound is reported: its structure was established by single crystal X-ray diffraction, and by spectroscopic methods. Crystallographic analysis indicated the presence of a co-crystallised related dicinnamamide, namely the new compound (E)-2,3-dehydroputrescine-1,4-dicinnamamide, whose occurrence was confirmed by LC-MS analysis. An interesting evolutionary issue arises, following the observation that the cinnamamides produced by Pholiota spumosa bear an unsubstituted benzene ring, contrarily to those found in plants, which have always phenolic functionalities, and as such perform a variety of biological roles.

Published
2004

15. Fundamentals of Crystallography

Author

Giacovazzo, C., Monaco, Ugo Luigi, Artioli, G., Viterbo, D., Ferraris, G., Gilli, G., Zanotti, G., and Catti, M.

Published
2002

17. Crystal and Molecular Structure of Secoisolariciresinol

Author

Milanesio, M., Viterbo, D., Chattopadhyay, Sk, Kulshrestha, M., and Giovanni Battista APPENDINO

Subjects
secoisolariciresinol, lignan, structure, bioactivity, ab initio calculations
Abstract

The R,R-2,3-bis[(4-hydroxy-3-methoxyphenyl)methyl]-1,4-butandiol lignan secoisolariciresinol (1) is a constituent of Gymnosperms used in the treatment of benign prostatic hyperplasya. The results of crystallographic and ab initio theoretical studies are reported and discussed. In the crystal, the molecule of (1) assumes a clustered conformation, characterized by the facing of the two phenyl rings. This geometry is stabilized by the formation of a network of hydrogen bonds. Theoretical calculations indicate that: i) the intramolecular hydrogen bond O1−H1⋅⋅⋅O1' is the major factor dictating the facing of the two phenyl groups, while intermolecular hydrogen bonds and crystal packing have smaller effects; ii) the 1−4O⋅⋅⋅O non-bonded interactions in the vanillyl groups are important in determining the most stable conformation; iii) calculations with two explicit water molecules in the model give a good simulation of the local effects of a water solvent and indicate that (1) probably assumes a clustered conformation also in polar solvents.

Published
1999

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