SYNTHESIS AND PROPERTIES OF NOVEL PHOTOCROMIC CHIRAL POLYMERS CONTAINING PORPHYRIN MOIETIES

An intense attention is currently arisen to investigations dealing with porphyrins because of their peculiar properties. In fact, they are versatile chromophore whose properties can be easily tuned by their functionalization with different substituents and by metallation. For these reasons they are retained very interesting materials for their potential advanced technological applications such as optical limiters1,2, NLO materials3,4 and as artificial receptor for molecular recognition5,6. In addition, recently, intensive research activities have been directed towards chiral nanotechnology7,8 and the amplification of chirality of polymeric materials9,10. In this context we have retained of interest to synthesize optically active photochromic polymers bearing in the side-chain both a chiral group of one single configuration and the tetraarylporphyrinic moiety. All the obtained derivatives have been fully characterized and their spectroscopic properties have been compared with those of the corresponding low molecular weight monomers. In particular we have focused our attention on the chiroptical properties of these derivatives. The presence of a chiral group of one prevailing configuration interposed between the polymeric backbone and the porphyrin moieties, in fact, provides these macromolecules with the further possibility to assume a conformational dissymmetry of one prevailing screw sense which can be revealed by the presence in the circular dichroism (CD) spectra of dichroic bands related to the electronic transitions of the chromophore.