Metal-ion complexation and photochromism of triphenylmethane dye derivatives incorporating monoaza-15-crown-5 moieties

Three types of triphenylmethane leuconitrile derivatives incorporating one, two, and three monoaza-15-crown-5 moieties have been designed to attain photocontrol of metal-ion complexation primarily by intramolecular electrostatic repulsion. Photochromism of the crowned triphenylmethane leuconitriles is influenced by the cation complexation of their crown ether moiety to a considerable extent. Molecular orbital calculations allowed some prediction regarding the possibility of photochemical control of metal-ion complexation by the photochromic crown ethers. High efficiency in the photocontrol has been evidenced by electrospray-ionization mass spectrometry, NMR spectroscopy, and thermal reaction kinetics.