EFFECT OF COMPLEXATION ON SPECTRAL AND KINETIC-PROPERTIES OF CROWN-SUBSTITUTED PHOTOCHROMIC SPIRONAPHTHOXAZINES

The insertion of benzo-15-crown-5 or benzo-18-crown-6 as a substituent at the 9'-position of a spironaphthoxazine molecule increases the lif etime of the open form of spironaphthoxazine by a factor of ca. 2. The complex formation between the crown groups and Mg2+ or Ba2+ ions chan ges the lifetime slightly. The addition of benzo-18-crown-6 at the 5'- position leads to an increase in the lifetime of the open form by an o rder of magnitude and the appearance of absorption with a maximum at 1 6420 cm(-1) under dark conditions, which testifies to the stabilizatio n of the open form. The addition of Ba2+ ions to this compound results in a further increase in the lifetime by ca. 35% due to complex forma tion. The luminescence of the benzo-15-crown-5-substituted compound is probably caused by both the complexation with Mg2+ and the photochemi cal reaction induced by photoactive light and is accompanied by the ir reversible loss of photochromism.