Synthesis And Properties Of Novel Photochromic And Electrochromic Compounds

Chameleon materials have become one of hot topics of functional materialscurrently. Materials possessing both photochromic and electrochromic propertiesmaybe show multiple molecule states, so they have important potential applicationsin the field of information storage.In the dissertation, a series of triphenylamine derivatives, including chalconescontaining triphenylamine units, diarylethenes bearing triphenylamine moieties,triphenylamines containing more diarylethenes units and diarylethene containing twotriphenylamine units, were synthesized by Vilsmeier, Kishner-Wolff-Huang,Ullmann and McMurry reactions, which were characterized by1H NMR,13C NMRand MS.Liquid state electrochromic devices were fabricated with chalcones containingtriphenylamine units to study the electrochromic properties byspectroelectrochemical experiments. The results showed that these compoundsexhibited good electrochromism, with a color change from yellow to blue whenapplied potentials were0and2.8V. The wavelengths of the minimum reflectanceshift from442~457nm to696~752nm according to the different devices ofcompounds. The coloring and bleaching time is in the range of2.9~4.2s and1.7~3.3s, respectively.Photochromic properties of diarylethenes bearing triphenylamine moieties weresynthesized and their properties were studied. The results showed that thesecompounds exhibited reversible photochromism, changing between colorless andyellow by alternating irradiation with UV light (302nm) and blue light (450nm).The cyclization and cycloreversion quantum yield is0.12~0.15and0.14~0.18,respectively. In the process of photochromism, fluorescence intensity would bereduced and recovered successively, which was quenched to about40%whenarriving at the photostationary state. Solid state electrochromic devices werefabricated with different diarylethenes bearing triphenylamine moieties, theexcitation potentials of electrochromism of devices for six compounds were obtainedby the electrochemical experiments, as well as the electrochromic performances ofthese materials were evaluated. The results showed that the excitation potentials are3.63~4.40V and the equivalent capacities of electrochromic layer in devices were inthe range of4.5to7.5μF. The results of spectroelectrochemical experiments showed that TPADAE compounds presented good electrochromic stabilities. Thewavelengths of the minimum reflectance of the devices were found in the range of709.7~781.7nm and the devices rendered blue with applying the excitationpotentials. The coloring and bleaching time was in the range of8.6~12.1s and8.9~12.8s, respectively.The photochromic properties for triphenylamines containing more diarylethenesunits were investigated, which showed that the cyclizations of only one unit in themolecular could be come into photochromic reaction. The cyclization andcycloreversion quantum yield is in the range of0.11~0.14and0.08~0.10,respectively. The dynamics model of cyclization and cycloreversion reaction wasfounded, in which the rate constant of cyclization reaction is0.003, and thecycloreversion is between0.065~0.079. The electrochemical experiments indicatedthat the equivalent capacity of electrochromic layers in the devices were in the rangeof2.58~3.55μF, The spectroelectrochemical experiments could give that theminimum reflectance wavelengths of the devices for triphenylamines derivativescontaining more diarylethenes units were between of690~772nm, and diarylethenederivative containing two triphenylamine units didn’t show the photochromicproperty, as well as the minimum reflectance wavelength of the device was found at765nm with applying4.1V excitation potential.