Photochromic switchable pendant indolyl fulgimide polypyrrole

The photochromic switchable 2-indolyl fulgimide functionalized pyrrole monomer is synthesized and ascertained by spectroscopic techniques. The absorption and emission band of monomer due to intramolecular charge transfer (ICT) state exhibit typical bathochromic shift from nonpolar to polar solvents. The molecular geometry and bandgap energy of monomer in open form as well as closed form are calculated by B3LYP/6-31 G (d) with Gaussian 03 program package. The functionalized pyrrole monomer is electropolymerized by cyclicvoltammetric method on an electrode. The polymer indicated a completely reversible photoswitching between two isomers of open and closed form 2-indolyl fulgimide moiety, which are stable over many cycles of operation by UV/visible light sources. The closed form of polymer exhibit fluorescence quenching attributed to the energy transfer from conductance band of polypyrrole to closed form of 2-indolyl fulgimides unit. This fluorescence quenching system controls the conductance of conducting polymer in molecular electronics and molecular switches.