Multistimuli-responsive materials based on a zinc(II) complex with high-contrast and multicolor switching

The development of stimulus-responsive luminescent materials, especially those based on a single compound exhibiting multicolor and high-contrast (Delta lambda(em) >= 100 nm) chromic properties, is a critical challenge. In this work, we synthesized and characterized a zinc(ii) complex (1). As expected, 1 displays aggregation-induced emission enhancement (AIEE) in THF/H2O mixtures, and remarkable multicolor switching under external stimuli in the solid state. Complex 1 shows reversible mechanochromic luminescence behavior with a large wavelength shift (Delta lambda(em) = 100 nm) during the grinding-fuming cycles, due to the phase transformation between the crystalline and amorphous states. More impressively, 1 exhibits obvious acidochromic properties (Delta lambda(em) = 130 nm) which originate from the adsorption of vapor and a gas-solid reaction on the crystal surface. Furthermore, 1 exhibits electrochemical oxidation behavior accompanied by quenching of yellow-green emission due to the overlap of an emission band and an absorption band. The above-mentioned color changes under ambient light can also be observed by the naked eye during the mechanical, acid-base vapor and electrical stimulation. Based on the high-contrast and multicolor switching, complex 1 was successfully developed into test papers and films in the field of rapid detection of mechanical stimuli and HCl/NH3 vapors.

Automated summary

The development of stimulus-responsive luminescent materials, especially those with multicolor and high-contrast chromic properties, is a critical challenge. In this study, a zinc(ii) complex was synthesized and characterized, showing aggregation-induced emission enhancement in THF/H2O mixtures and multicolor switching under external stimuli in the solid state. The complex exhibited reversible mechanochromic luminescence behavior and acidochromic properties, as well as electrochemical oxidation behavior. Based on its high-contrast and multicolor switching, the complex was successfully used in the field of rapid detection of mechanical stimuli and HCl/NH3 vapors.