K. Kimura et al., Metal-ion complexation and photochromism of triphenylmethane dye derivatives incorporating monoaza-15-crown-5 moieties, J AM CHEM S, 122(23), 2000, pp. 5448-5454
Three types of triphenylmethane leuconitrile derivatives incorporating one,
two, and three monoaza-15-crown-5 moieties have been designed to attain ph
otocontrol of metal-ion complexation primarily by intramolecular electrosta
tic repulsion. Photochromism of the crowned triphenylmethane leuconitriles
is influenced by the cation complexation of their crown ether moiety to a c
onsiderable extent. Molecular orbital calculations allowed some prediction
regarding the possibility of photochemical control of metal-ion complexatio
n by the photochromic crown ethers. High efficiency in the photocontrol has
been evidenced by electrospray-ionization mass spectrometry, NMR spectrosc
opy, and thermal reaction kinetics.