Crown-containing spirooxazines and spiropyrans - 1. Synthesis and the anion-"capped" complexes of photochromic aza-15-crown-5 ethers with flexible spacers

Methods for the synthesis of new spironaphthooxazines containing an aza-15- crown-5 fragment in two different positions (5' and 9') were developed. The spectral and photochemical properties of these compounds suggest that two competitive complexation processes occur with alkaline-earth or rare-earth metal cations differing in efficiency and selectivity. A metal cation occup ies the optimum position in the crown-ether cavity with respect to the dono r oxygen atom of the merocyanine form of the dye and thus can affect more s trongly its spectral and photochemical properties than in the case of inter molecular interaction.