Design and Studies of Diarylethene-Containing Ligands and Their Coordination Compounds

Abstract

Photochromic compounds are those that are capable of undergoing light-induced reversible transformation between two forms having distinguishable absorption characteristics. They are among the most promising materials for optical data storage, optoelectronics, and molecular switching devices. Organic diarylethene derivatives have recently received much attention, as they have been shown to possess excellent fatigue resistance and thermally irreversible photochromic behaviors. However most of these studies are directed toward the molecular design of the organic framework, while studies on the exploitation of these diarylethenes as ligands to form metal complexes are extremely rare. We recently reported the photosensitization of a spirooxazine-containing ligand by the 3MLCT excited states of rhenium(I). We believe that through judicious design, a new series of functionalized diarylethene molecules capable of serving as versatile ligands could be synthesized. This may open up new avenues for the discovery of new classes of interesting ligands and metal-containing photochromic materials, such that through the incorporation of different metal centers, ready tuning of the excitation wavelength and photochromic behavior may result, without the need for difficult and tedious synthesis and preparation of elaborate organic molecular framework. Herein, we report the syntheses, crystal structures, and sensitized photochromic properties of diarylethene-containing ligands and their coordination compounds.