Fine Tuning the Energetics of Excited-State Intramolecular Proton Transfer (ESIPT): White Light Generation in A Single ESIPT System

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• 作者：Kuo-Chun Tang ; Ming-Jen Chang ; Tsung-Yi Lin ; Hsiao-An Pan ; Tzu-Chien Fang ; Kew-Yu Chen ; Wen-Yi Hung ; Yu-Hsiang Hsu ; Pi-Tai Chou
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：November 9, 2011
• 年：2011
• 卷：133
• 期：44
• 页码：17738-17745
• 全文大小：989K
• 年卷期：v.133,no.44(November 9, 2011)
• ISSN：1520-5126

文摘

Using 7-hydroxy-1-indanone as a prototype (I), which exhibits excited-state intramolecular proton transfer (ESIPT), chemical modification has been performed at C(2)鈥揅(3) positions by fusing benzene (molecule II) and naphthalene rings, (molecule III). I undergoes an ultrafast rate of ESIPT, resulting in a unique tautomer emission (位_max 530 nm), whereas excited-state equilibrium is established for both II and III, as supported by the dual emission and the associated relaxation dynamics. The forward ESIPT (normal to proton-transfer tautomer species) rates for II and III are deduced to be (30 ps)^鈭? and (22 ps)^鈭?, respectively, while the backward ESIPT rates are (11 ps)^鈭? and (48 ps)^鈭?. The ESIPT equilibrium constants are thus calculated to be 0.37 and 2.2 for II and III, respectively, giving a corresponding free energy change of 0.59 and 鈭?.47 kcal/mol between normal and tautomer species. For III, normal and tautomer emissions in solid are maximized at 435 and 580 nm, respectively, achieving a white light generation with Commission Internationale de l鈥橢clairage (CIE) (0.30, 0.27). An organic light-emitting diode based on III is also successfully fabricated with maximum brightness of 665 cd m^鈥? at 20 V (885 mA cm^鈥?) and the CIE coordinates of (0.26, 0.35). The results provide the proof of concept that the white light generation can be achieved in a single ESIPT system.