Dicyanopyrazine studies. Part VII: Solid state absorption spectra and aggregation behavior of aminovinylpyrazine dyes containing a long chain alkyl group

The solid state absorption maxima of aminovinylpyrazine dyes containing long chain alkyl groups were changed drastically by the differences in their molecular stacking. The spectral shift from solution to the solid state was evaluated by the Delta lambda values, and the shift was correlated with substituent effects and their three dimensional molecular structures. Related dyes were synthesized by the nucleophilic substitution of 2,3-dichloro-5,6-dicyanopyrazine with various Fisherʹs base type enamines having long alkyl chain groups.