A series of mono-, bis- and tris-4-(naphthopyran-3-yl)phenyl substituted methanols were efficiently synthesised using a 4-(naphthopyran-3-yl) phenyllithium intermediate. The resulting substituted methanols displayed good photochromism leading to the reversible generation of red-orange photomerocyanines. Acidic dehydration of the methanols gave intensely coloured cations which, upon subsequent UV irradiation, reversibly generated cationic photomerocyanines with long wavelength absorption maxima at ca. 640 nm.
|Number of pages||6|
|Journal||Dyes and Pigments|
|Publication status||Published - Apr 2013|