Isolation and characterization of protonated merocyanine dyes from spiroindolino photochromes

CHED 826

Rebecca R. Faber and J. Thomas Ippoliti. Department of Chemistry, University of St. Thomas, 2115 Summit Ave., OSS 402, St. Paul, MN 55105
The analysis and characterization of the protonated form of spiroindolino photochromes is currently of interest to many researchers. The isolation of the open, protonated form of three different spiroindolino photochromes was successfully performed. Protonation was accomplished from the addition of two separate acidic reagents, HCl gas and HBF4 etherate, and the use of UV light. Proton NMR was used to characterize the three highly colored, protonated photochromes. The synthesis of two of the starting photochromes will be presented.