257282-10-3Relevant academic research and scientific papers
Crown-containing spironaphthoxazines and spiropyrans. 2. Influence of metal cations on the photochromic properties of spironaphthoxazines linked with aza-15(18)-crown-5(6) ethers
Strokach,Fedorova,Gromov,Koshkin,Valova,Barachevsky,Alfimov,Lokshin,Samat,Guglielmetti
, p. 58 - 66 (2002)
Spironaphthoxazines linked with aza-15(18)-crown-5(6) fragments were synthesized and studied for the first time. Addition of alkaline-earth cations to solutions of crown-containing spironaphthoxazines causes a hypsochromic shift of the absorption band of the spiro form and a bathochromic shift of the absorption band of the merocyanine form, shifts the equilibrium to the merocyanine form, and changes the lifetime of the photoexcited merocyanine form. The spectral and kinetic data were used to propose a mechanism of complexation and calculate the stability constants of the resulting complexes. The complexation involves the crown fragment and the merocyanine oxygen atom. The type of the complex is determined by the cation nature and size.
Effect of metal cations on the photochromic properties of spironaphthoxazines conjugated with aza-15(18)-crown-5(6) ethers
Fedorova, Olga A.,Strokach, Yuri P.,Gromov, Sergey P.,Koshkin, Alexander V.,Valova, Tatjana M.,Alfimov, Michael V.,Feofanov, Alexei V.,Alaverdian, Iouri S.,Lokshin, Vladimir A.,Samat, Andre,Guglielmetti, Robert,Girling, Reuben B.,Moore, John N.,Hester, Ronald E.
, p. 1137 - 1145 (2007/10/03)
Spironaphthoxazines conjugated with aza-15(18)-crown-5(6)-ether moieties at the 6′-position of the naphthalene fragment (crown-containing spironaphthoxazine, CSN) were synthesised and studied for the first time. The addition of Li+ and alkaline earth (Mg2+, Ca2+, Sr2+ and Ba2+) metal cations to CSN solutions results in a hypsochromic shift of the UV absorption band of the spiro form and a bathochromic shift of the absorption band of the merocyanine form in the visible region. In addition, the equilibrium shifts to the merocyanine form, and the lifetime of the photoinduced merocyanine form increases. Analysis of the spectral and kinetic data allows a complexation scheme to be proposed and the stability constants of the resulting complexes to be calculated. According to the results obtained, the complexation with Li+ and alkaline earth metal cations in acetonitrile initially involves the crown ether moiety; the participation of the merocyanine oxygen atom in the complexation process occurs at a high metal cation concentration. The UV-induced isomerisation of CSN into the merocyanine form causes a decrease of the cation binding ability.
