Smart multi-stimuli responsive organic materials have become increasingly favored due to their advantages of high stability and easy regulation.In this study,a cyanostilbene derivative((αZ)-2-chloro-α-[(4-methoxyphenyl)methylene]-5-pyridinehyde,TAR)was successfully synthesized,and its polymorphs(TAR-1 and TAR-2)exhibited multiple responsive behaviors under different stimulus conditions.TAR-1 is supposed to have excellent mechanical properties,while TAR-2 shows fascinating heterotropic photochromism(green-cyan-yellow)under different intensities of ultraviolet(UV)irradiation,which has never been reported in previous studies.Further investigation revealed that this was attributed to different degrees of[2+2]cycloaddition induced by UV light.In addition,both polymorphs could be protonated during Trifluoroacetic acid fuming and deprotonate automatically after fuming,accompanied by the significant variation in fluorescence.Finally,two scenarios were designed based on their unique stimuli-responsive properties,which proved their promising potential in fields of information security and anti-counterfeiting encryption.
A bolaform （BNC10） and single-headed （HNOA） amphiphilic Schiff bases containing naphthyl group were designed and their Langmuir-Blodgett films were investigated. It was found that both the LB films show acidichromism, i.e. a reversible color change upon alternatively exposing the films to HC1 and NH3 gases, respectively. It was further found that the bolaform Schiff bases film could trap NH3 gas during the acidichromic process.
A new Schiff base containing carbazole group (CzSB) was synthesized. Although the compound can not form stable monolayer at air/water interface itself, it does form stable monolayers by mixing with stearic acids as verified from the surface pressure area measurements. The mixed monolayers can be deposited by vertical dipping method. UV Spectroscopic studies of the mixed LB films reveal a broadening and red shift of the absorption spectra compared to those of CzSB in the ethanol solution, which confirms the formation of organized aggregates of the compounds in the mixed LB films. An ordered LB film was obtained as confirmed by using low angle X ray diffraction. The mixed LB film shows acidichromism, that is, the colors of the LB films can be reversibly changed upon exposing to HCl and NH 3 gas alternatively. On the basis of FT IR measurement, it is proposed that the protontation of the imine group in the compound is the reason for the acidichromism.
1,3,3-tnmethyl-spiro[mdolino-2,3’-[2H]naphtho[2,1-b] [1,4]oxazine(SP1) and 1,3,3-trimen-thyl-9-methoxy-spiro[indolino2,3’-[2H]naphtho[2,1-b] [ 1,4]oxazine] (SP2) react with hydrochloric acid to form the complex SP HCl in isopropanol solution at room temperature The absorption maxima of these complexes are 440 and 463 nm respectively In acidic media,the opening form of spirooxazine can react with hydrochloric acid to form the complex PMC HCl via zwittenon form The absorption spectra of PMC HCl are obviously hypsochromic shifted compared with the reported spectra of the complex in neutral media In the mean time,the thermal stability of the complex is increased.The first order kinetics for the decoloration process of the acidichromic product of the opening form was determined and the lifetimes of these products are 180 and 200 s,respectively.
