Synthesis And Properties Of New Photochromic Materials Based On Schiff Base Derivatives

In recent years,photochromic materials have attracted much attention due to their potential applications in chemistry,physics and biological fields.More and more people pay attention to their design and property.Schiff base derivatives are facilely prepared and low cost,they have unique structural properties,so that they are widely used in photochromism.In this paper,a new photochromic compound with aggregation-induced emission property was designed and synthesized.And a new photochromic system based on the fluorane salicylaldehyde hydrazone metal complexes was developed.First,a reversible photochromic molecule of 4-(1,2,2-triphenylvinyl)aniline salicylaldehyde hydrazone(1)with aggregation-induced emission(AIE)properties was developed.Compound 1 exhibits typical AIE properties due to restricted intramolecular rotations(RIR)and excited-state intramolecular proton transfer(ESIPT)processes.As a photochromic molecule,1 shows reversible color and fluorescence changes upon UV light irradiation with good fatigue resistance.More importantly,conversion rate from its irradiated form to initial form is controllable by temperature and long wavelength light irradiation,which make it suitable for photo-patterning materials with erasable property.Second,a new photochromic system based on the fluorane salicylaldehyde hydrazone metal complexes was developed.They were facilely prepared by two-step synthesis with low cost,which showed good photochromic properties both in solution and solid matrix upon UV light irradiation.The photochromic mechanism studies show that fluorane salicylaldehyde hydrazone metal complexes were found to undergo intramolecular ring-open reactions upon UV irradiation,due to the isomerization of salicylaldehyde moieties from enol form to keto form as well as color change upon in solution and in solid matrix.And the system showed good fatigue resistance.This photochromic system can be successfully used in solid matrix,which makes it suitable for the photoprinting materials and anti-counterfeiting related applications.