2,924 research outputs found
Luigi Angiolini - Life in Service to Tuscany
No full textThis bachelor's thesis presents in a chronological order, the life of a Tuscan aristocrat Luigi Angiolini (1750-1821). He was a writer, traveller and diplomat, active in the period of the Habsburg reforms, the French Revolution, the Napoleonic rule, and the restoration in Italy. Based on the available literature and sources, this thesis maps Angiolini's youth, his journey to England and Scotland, his diplomatic career in Paris in the service of Ferdinand III, Grand Duke of Tuscany, as well as his final years spent in the countryside with his family. Angiolini's varied life and his openness to modern ideas allow for conceiving this protagonist as a typical man of his times, while on the basis of his interests and activities simultaneously elucidating the entire historical period in a wider context
Luigi Angiolini - Life in Service to Tuscany
No full textThis bachelor's thesis presents in a chronological order, the life of a Tuscan aristocrat Luigi Angiolini (1750-1821). He was a writer, traveller and diplomat, active in the period of the Habsburg reforms, the French Revolution, the Napoleonic rule, and the restoration in Italy. Based on the available literature and sources, this thesis maps Angiolini's youth, his journey to England and Scotland, his diplomatic career in Paris in the service of Ferdinand III, Grand Duke of Tuscany, as well as his final years spent in the countryside with his family. Angiolini's varied life and his openness to modern ideas allow for conceiving this protagonist as a typical man of his times, while on the basis of his interests and activities simultaneously elucidating the entire historical period in a wider context
Polymethacrylic zinc porphyrin: A new approach to chiral recognition
No full textA methacrylic homopolymer bearing in the side-chain achiral zinc tetraarylporphyrin moieties, has been studied as macromolecular chromophoric host to determine the absolute configuration of ,-diamines. The polymeric material resulted able to bind the chiral guest through amine nitrogen/zinc coordination to form a complex which exhibits exciton-coupled bisignate Circular Dichroism (CD) spectra, due to stereodifferentiation leading to a preferred porphyrin helicity. The sign of CD signal reflects the absolute configuration of diamine and the method turns out very sensitive, requiring only few microgram quantities of guest compound.
To our knowledge this is the first example of absolute configuration assignment to chiral molecular compounds by means of a polymeric derivative containing in the side-chain metallo-porphyrins moieties
CHIROPTICAL PROPERTIES OF AZOBENZENE DIMERS
No full textPhotochromic polymers have received considerable attention for their potential advanced technological applications (optical data storage, holographic memories, waveguides, chemical photoreceptors, etc.)1,2.
Recently we have observed3 that it is possible to photomodulate the chiroptical properties of thin films of chiral photochromic polymers, bearing in the side-chain both a chiral group of one single configuration and the trans-azoaromatic moiety, by irradiation with circularly polarized (CP) light of one single L or R rotation sense. This unexpected new phenomenon seems to open new possibilities for the use of azobenzene containing materials as chiroptical switches, besides of the usual applications in optics.
With the aim to delve into this phenomenon, we have retained of interest to study dimeric derivatives having moieties of opposite absolute configurations (Fig. 1) which correspond to the smallest section of polymer where interchromophore interactions can be present. Their CD spectra, both in solution and in the solid state, are characterized by strong exciton couplets (about one third of the signal intensity measured for the corresponding polymer) which are the mirror image of each other. In this work we present the preliminary results on the photomodulation of the chiroptical properties these oligomeric compounds dispersed in a PMMA matrix, by irradiation with CP- or EP-light.
Fig. 1: Structure of investigated dimeric models and CD spectra of a film on fused silica as prepare (─) and after irradiation with EP-L (--).
The financial support by Consortium INSTM (FIRB2001 ‘RBNE01P4JF’) is gratefully acknowledged.
[1] S. Xie, A. Natansohn, P. Rochon, Chem. Mater., 1995, 5, 403.
[2] T. Todorov T, L. Nikolova, N. Tomova, Appl. Opt., 1984, 23, 4588.
[3] L. Angiolini, R. Bozio, A. Daurù, L. Giorgini, D. Pedron, G. Turco, Chem. Eur. J., 2002, 8, 4241
recensione di "Smart Light-Responsive Materials: Azobenzene-Containing Polymers and Liquid Crystals" Yue Zhao, Tomiki Ikeda Eds. Wiley-Blackwell, 2009
No full textPolimeri multifunzionali otticamente attivi per applicazioni avanzate, Keynote su invito
No full textOptically active polyalkylthiophenes: synthesis and polymerization of chiral, symmetrically substituted, quinquethiophene monomer
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