Coordination and light modulated dynamic optical switches of terpyridine-derived spiropyran for time-resolved information encryption

The development of the light-controlled assembly of smart materials for advanced information encryption with time-dependent optical characteristics is essential to meet the increasing demand on fabricating multiple optical materials for encryption security. In this work, the integration of terpyridine-derived photochromic spiropyran (Tpy-SP) as Zn2+ ion chelating agent and photo-regulator building blocks endows the materials with dynamic assembly-induced optical functionality. Under UV light irradiation, the Tpy-Zn2+-SP will be transformed into Tpy-Zn2+-MC, which forms coordinated architecture with distinct optical properties from that of Tpy-MC form. Modulated by the coordination, Tpy-Zn2+-MC and Tpy-MC show obviously different fading rate with the achievement of time-resolved multicolor optical switches. The temporal multioptical features promote the light-controlled switches as a promising candidate for time-dependent confidential materials, including dynamic optical patterns and multilevel encryption, and the relative encrypted data that could only be identified at a specified time.