Synthesis of Mesoporous Silicates with Controllable Pore Size Using Surfactant Ruthenium(II) Complexes as Templates
✍ Scribed by V.W.-W. Yam; B. Li; N. Zhu
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 187 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0935-9648
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✦ Synopsis
2.1 eV absorbance observed by spectroelectrochemistry. This transition, which occurs in the visible region, grows in at high potentials beyond 0.45 V and gives rise to the third color state. The luminance measurements are reversible between ±0.25 V and 1.1 V. After 1.1 V, an increase in luminance is observed which corresponds to over oxidation of the film and was not reversible.
In summary, we report a new alkylenedioxythiophene derivative, poly(spiroBiProDOT), which exhibits three color states and shows a luminance change of 30 % at intermediate potentials. Since the change in luminance occurs around the E 1/2 of the polymer, this may lead to electrochromic devices with greater stability and longer lifetimes. The peak of oxidation (E p,m ) for the monomer (1.45 V) and the E 1/2 of the polymer (0.51 V) were significantly higher than the rest of the alkylenedioxythiophene family. Luminance studies showed that the polymer was initially cathodically coloring, exhibiting a dark red film in the neutral state, and subsequently anodically coloring, exhibiting a dark blue color in the oxidized state. The unique anodically coloring characteristic of the polymer was attributed to the peak at 2.1 eV, which began to grow in at 0.55 V and higher potentials. Although the origin of the peak is unknown at this time, future studies are underway to identify the transition to which it corresponds.
Experimental
Synthesis of SpiroBiProDOT: A 500 mL flame dried round bottom flask, equipped with a soxhlet extractor containing activated 4 molecular sieves, and an Argon inlet, was charged with 250 mL of dry toluene, 11.3 g (0.083 mol) of pentaerythritol, 2.0 g (0.014 mol) of 3,4-dimethoxythiophene, and 0.26 g (1.38 mmol) of p-toluenesulphonic acid. The mixture was then refluxed under Argon for 24 h. The black mixture was then cooled and washed with 200 mL water in a separatory funnel. After, the organic layer was dried over MgSO 4 and the solvent was removed by rotary evaporation. The resulting yellow solid was eluted through a silica gel plug with methylene chloride. The white solid obtained was recrystallized from chloroform to yield (60 %) white crystals. m.p. = 228±229 C. k max = 254 nm, e = 15 133 M ±1 cm ±1 . 1 H NMR d (CDCl 3 ) 4.06 (s,