Quantum-chemical investigation of the triplet-triplet absorption in photochromic indolinespiropyrans

Autor: Lisyutenko, V. N., Barachevskii, V. A.
Zdroj: Theoretical and Experimental Chemistry; May 1988, Vol. 24 Issue: 3 p284-291, 8p
Abstrakt: The triplet-triplet absorption spectra of the initial and photoinduced forms of unsubstituted and methoxy- and nitro-substituted indolinespiropyrans were calculated by the CNDO/S method. An interpretation of the experimental data with respect to the absorption of indolinespiropyrans in the visible region is proposed on the basis of the results. The presence of long-wave triplet-triplet absorption in the spectral region > 800 nm is indicated. A suggestion is made about the nature of the kinetic changes in the absorption spectra of nitro-substituted indolinespiropyrans during the photochromic transformations. An explanation of the nature, the structure, and the complexity of the kinetics of decay of the absorption band in the region of 400–460 nm is given in terms of the cis-isomeric form, which is formed immediately after photoexcitation of the indolinespiropyran. The nature of the triplet-triplet absorption of the trans isomers of the colored form was established. An analysis is made of the orbital nature of the triplet states of the initial and photoinduced forms of unsubstituted and methoxy- and nitrosubstituted indolinespiropyrans.
Databáze: Supplemental Index