A supramolecular chiroptical switch based on chitosan and anionic porphyrin complex film

Abstract

A supramolecular chiroptical switch based on chitosan and tetrakis (4-sulfonatophenyl) porphine (TPPS) complex films was prepared. The reversible changes of the chirality of the complex films were studied by UV-vis and circular dichroism (CD) spectra. It was found that the chirality of the complex films can be wiped off by being exposed to NH3 gas and subsequently recovered by being exposed to moist HCl gas. The complex film is stable and can stand at least 20 cycles of the switching to NH3 and HCl gases. There is no change in the above properties after the complex films were store in the air at room temperature. © 2007 The Society of Polymer Science.