Spironaphtoxazines produced from crown-containing dihydroisoquinolines: Synthesis and spectroscopic study of cation-dependent photochromism

Synthesis and photochromic properties of a novel spironaphtoxazine (SNO) obtained from a crown-containing dihydroisoquinoline are described. The comparison of spectral and kinetic properties with that of a crown free SNO is performed. For a crown-containing SNO, the complex formation with alkaline earth metal cations occurs both for spiro (S) and merocyanine (M) forms of the molecule. For the cations of large size (for instance, Ba2+) the formation of sandwich complex was found. For a crown free SNO, only M-form complex with metal cation is possible. In all cases, the complex formation affects both on the position of the M-form absorption maximum and the M-form characteristic lifetime.