Photochromic 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.
L. Angiolini, T. Benelli, L. Giorgini (2007). CHIROPTICAL PROPERTIES OF AZOBENZENE DIMERS. BARCELONA : EUROPEAN MATERIALS Research society.
CHIROPTICAL PROPERTIES OF AZOBENZENE DIMERS
ANGIOLINI, LUIGI;BENELLI, TIZIANA;GIORGINI, LORIS
2007
Abstract
Photochromic 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
