Synthesis And Properties Of Novel Solvatochromic Or Photochromic Triphenylamines

Organic fluorescent dyes and organic photochromic materials,as two kinds of important optical functional organic materials,have made important contributions in the fields of information storage,display technology and detection.In the information age,the demand for optical functional organic materials is becoming more and more high.By the rational design of molecular structure,the luminescence and photochromic properties would be improved.Series of triphenylamine derivatives,including anthraquinone dyes and dithienylcyclopentenes bearing triphenylamine units,were synthesized by Ullman,McMurry and Suzuki reactions.The structures of target compounds were characterized by mass spectrometry(MS),nuclear magnetic resonance spectroscopy(NMR),infrared spectroscopy(IR)and X-ray single crystal diffraction,and their spectral properties were studied in detail.First,the spectral properties and solvent effects of five triphenylamineanthraquinone dyes(dyes 1-5)with different strong push-pull electronic structures in different solvents were studied in detail.The results showed the dyes showed obvious intramolecular charge transfer characteristics,longer absorption and emission wavelengths.For all dyes,with the increase of solvent polarity,the fluorescence emission showed significant red shifts with wavelengths ranging from 138 nm to 192 nm and the emission color changed from blue,green,yellow,orange to violet red.Additionally,the Stokes shifts increased obviously with the maximum values in range of 210-306 nm and they were linearly related to solvent polarity function ET(30).In the solvents with low polarity,the dyes showed higher fluorescence quantum and longer lifetimes,however,in the solvents with high polarity the fluorescence was quenched.Electrochemical studies of five dyes suggested that the different substituted phenylamine groups attached to anthraquinone unit could lead to tunable redox potentials and energy levels.Secondly,the photochromic properties of three dibenzothienylcyclopentenes bearing triphenylamines(DT1-3)were studied.In dichloromethane,upon alternating irradiation with UV light(302 nm)and visible light(450 nm)of the compounds,reversible cyclization/cycloreversion reactions occured,and the color changed between colorless and yellow.For all compounds,the stationary colorization states were achieved upon irradiation with UV light for about 40 s,the yellow solutions were bleached upon irradiation with visibile light for about 20 s,and clear isosbestic points were observed at 295-302 nm.These compounds exhibited strong absorbtion and fluorescence emission,and the fluorescence quantum yields were 0.46-0.52.Compared with the initial states,the fluorescence intensities were reduced by 30-40 % in stationary colorization states.In addition,no obvious degradation of the compounds was observed in n-hexane after five cycles of cyclization/cycloreversion reactions upon alternating irradiation with UV and visible light.Finally,the photochromic properties of the dithienylcyclopentene 4-(4-(2-(5-chloro-2-methylthiophen-3-yl)cyclopent-1-en-1-yl)-5-methylthiophen-2-yl)-N,N-diphenylaniline(DTETPA)was investigated.Both in different organic solvents and in homogenous solid film doped with poly(methyl methacrylate,PMMA),the color of the dithienylcyclopentene changed between colorless and red upon alternating irradiation UV light(365 nm)and visible light(500 nm).The stationary colorization states were achieved upon irradiation with UV light in 5-8 min,and the fluorescence intensities were decreased by more than 85 %.The results indicated that the synthesized compound had high fluorescence modulation efficiency and was good fluorescent switch molecule.