| Abstrakt: |
The corresponding photochromic 5',7'-disubstituted indolinospirochromenes were obtained by the reaction of 4,6-dialkoxy-5-nitrosalicylaldehydes, as well as 4,6-dimethyl-5-nitrosalicylaldehyde, with 1,3,3-trimethyl-2-methyleneindoline. Bulky electron-donor substituents in the ortho,ortho' positions relative to the nitro group give rise to a hypsochromic shift of the long-wave absorption band of the photomerocyanine as a consequence of steric hindrance to conjugation of the nitro group in combination with the electronic effect along the chromophore chain on the nitrogen atom of the indoline part of the molecule. |
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