Acidichromism of indolinospirooxazines in isopropanol

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.

Acidichromism in the Mixed Langmuir-Blodgett Films of Stearic Acid with a Carbazole-containing Schiff Base

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.

Effects of Aromatic Stabilization Energies on Photochromism of New Asymmetrical Azaindole-Containing Diarylethenes

Three new asymmetrical diarylethenes containing an azaindole moiety and a variable heteroaryl ring have been synthesized. Their properties, such as photochromism, fatigue resistance, thermal stability, acidichromism, and fluorescence, were systematically investigated to elucidate the effects of aromatic stabilization energies （ASE） of the heteroaryl moieties. The results indicated that thermal stability decreased with the increment of the aromatic stabilization energies of the variable heteroaryl rings in the order of thiazyl〈thienyl〈pyrrolyl. Moreover, the dual switching behaviors of these azaindole-containing diarylethenes were also studied by the stimulation of acid/base and light. Addition of trifluoroacetie acid to the solutions of these diarylethenes resulted in obvious hypochromie shifts, and their N-protonated forms also exhibited favorable photochromism.

Synthesis and Photochromism of Novel Spiro（indoline-2,3＆#39;-naphtho [2,1-b] [1,4] oxazine）

A series of novel spirooxazine（SPO） derivatives containing nitrogen heterocycles was synthesized and characterized by 1H NMR spectra, Fourier transform infrared（FTIR） spectra, mass spectra（MS） and elemental analy- sis, and their photochromic behaviors were fully investigated in solvents and polymer media. In solvents, they dis- played excellent photochromism properties such as high photochromic response and fast thermal bleaching rate. Es- pecially, compounds 1 and 4 exhibited strong fluorescence intensities in dichloromethane solution. It was additionally found that compound 4 showed high fatigue resistence in poly（methyl methacrylate）（PMMA） film, and the thermal decay curves were fitted with biexponential function in PMMA film.