A multi-addressable molecular switch based on a novel diarylethene with an imidazo [4,5-f] [1,10] phenanthroline unit

A novel unsymmetrical diarylethene with an imidazo [4,5-f] [1,10] phenanthroline unit has been synthesized, and its properties including photochromism and fluorescence have been investigated. It showed favorable photochromism and functioned as notable fluorescence switches by photoirradiation in both solution and a poly (methylmethacrylate) film. Moreover, the interaction between the phenanthroline unit of its closed-ring isomer with trifluoroacetic acid caused a notable change in its absorption, accompanied by an evident color change from magenta to slateblue. Its fluorescence could be modulated by trifluoroacetic acid and triethylamine. By adding enough amount of trifluoroacetic acid in chloroform, its emission peak hypochromatic shifted from 501nm to 456nm, and the intensity increased significantly with a concomitant change of color from bright cyan to bright blue. However, its emission intensity decreased notably by 95% with a fluorescence color change from bright cyan to dark gray by the addition of triethylamine. Copyright (c) 2013 John Wiley & Sons, Ltd.