Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals, Vol.297, 255-262, 1997
Spiro(2H)-1-Benzopyran-2,9’-Fluorenes - Hyperchromic and Bathochromic Shifts of the Visible Absorption of Chromenes
The synthesis of spiro[fluorene-naphthopyrans] and spiro[fluorene-furano[3,2-f]chromenes] allowed us to quantify the role of fluorene moiety towards photochromic properties. Compared to corresponding diphenylchromenes, the extended Pi system delocalization causes a bathochromic shift of the visible absorption of the colored merocyanines. Whatever the right hand side in the studied series, an hyperchromic effect is observed.