Fast Isomerizing Methyl Iodide Azopyridinium Salts for Molecular Switches

The usefulness of azopyridinium methyl iodide salts for designing new promising light-controlled molecular switches is presented. Large absorbance changes have been produced in the samples by irradiation with light at λ = 355 nm. The thermal recovery of the initial state took place completely within 130−450 ms, which is much faster than that reported previously for other push−pull azobenzene-doped nematic mixtures.