Absorption and fluorescence of arylmethylidenoxindoles and isoindigo

作者：Lunak Stanislav Jr^*; Horakova Petra; Lycka Antonin

来源：Dyes and Pigments, 2010, 85(3): 171-176.

DOI：10.1016/j.dyepig.2009.11.001

• Absorption
• Fluorescence
• Density functional theory
• Isoindigo
• Arylmethylidenoxindole

A series of arylmethylidenoxindoles was synthesized by acid or base catalysed condensation of substituted aldehydes with oxindole. The products were formed as mixtures of Z- and E-isomers that were separated using column chromatography and identified by (1)H and (13)C NMR. The effect of substituents on absorption maxima was investigated both experimentally and theoretically, based on time dependent density functional theory. Low temperature absorption spectroscopy in a solvent glass enabled identification of the position of the 0-0 vibronic bands. The spectral features of the parent Z-benzylidenoxindole were compared to those of trans-isoindigo and trans-stilbene. Fluorescence of arylmethylidenoxindoles in solution was not observed, as E-Z isomerization represents a dominant deactivation channel after irradiation: when this geometrical isomerization was sterically hindered at low temperature solvent glass or in solid, fluorescence of planar Z-isomers was observed.

• 出版日期2010-5