高等学校化学学报

高等学校化学学报 ›› 2004, Vol. 25 ›› Issue (9): 1698.

• 研究论文 • 上一篇    下一篇

三氟乙酸对无金属卟啉-苝酰亚胺分子阵列激发态衰变过程的影响

孙景志1, 杨新国1,2, 李寒莹1, 黄骥1, 汪茫1   

  1. 1. 浙江大学高分子科学与工程系, 浙江大学硅材料国家重点实验室, 杭州310027;
    2. 湖南大学材料科学与工程学院, 长沙410082
  • 收稿日期:2003-11-11 出版日期:2004-09-24 发布日期:2004-09-24
  • 基金资助:

    国家自然科学基金(批准号:90101008)资助

Effect of CF3COOH on Decay Mechanism of the Excited State of a Free-base-Porphyrin-Perylene-Diimide Array

SUN Jing-Zhi1, YANG Xin-Guo1,2, LI Han-Ying1, HUANG Ji1, WANG Mang1   

  1. 1. State Key Lab of Silicon Materials, Department of Polymer Science & Engineering, Zhejiang University, Hangzhou 310027, China;
    2. College of Materials Science and Enginsering, Hunan University, Changsha 410082, China
  • Received:2003-11-11 Online:2004-09-24 Published:2004-09-24

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被引次数

3

摘要： 用紫外-可见吸收光谱和荧光光谱研究了CF3COOH浓度变化对CHCl3溶液中N-[p-5′-(m-10′,15′,20′-三苯基卟啉)基]-N′-正十二烷基-3,4:9,10-四羧基二酰亚胺分子阵列(TrPP-MDPTCDI)的光致激发态衰变机理的影响,发现无论激发无金属卟啉还是酰亚胺基元,分子阵列均表现出质子化无金属卟啉生色团的特征荧光发射.对电子结构的分析说明质子化使[H22+TrPP*-MDPTCDI]成为各种激发态中相对稳定的物种,因此,未质子化前占主导的从卟啉到酰亚胺基元的光致电子转移衰变途径在质子化后受到有效抑制,激发卟啉生色团(λ=439nm)直接得到[H22+TrPP-MDPTCDI*],并以辐射衰变方式回到基态;激发酰亚胺生色团(λ=491nm)得到的[H22+TrPP*-MDPTCDI]通过电荷分离态迅速弛豫到[H22+TrPP*-MDPTCDI],并辐射荧光,同时伴随少量的从酰亚胺到质子化无金属卟啉生色团的能量转移.

关键词: 质子化, 分子阵列, 电荷转移, 能量转移, 激发态

Abstract: The effects of CF3COOH concentration on the decay mechanism of a photo-excited free-base-porphyrin-perylene-diimide molecular array(TrPP-MDPTCDI) were investigated with UV-visible absorption spectroscopy and fluorescence spectroscopy. The data revealed that, the molecular array gave off a characteristic emission from the protonated free-base porphyrin upon the photo-excitation of both porpyrin and perylene-diimide subuntits. Based on the electronic structure, the protonation allowed the [H22+TrPP*-MDPTCDI] to be relatively stable in all the photo-excited species. As a result, the electron transfer from free-base-porpyrin to perylene-diimide, a predominate decay channel in the absence of CF3COOH was effectively inhibited, and the [H22+TrPP*-MDPTCDI] formed upon the excitation of protonated free-base porphyrin(λ=438 nm) relaxed directly to the ground state with fluorescence; while the [H22+TrPP*-MDPTCDI] formed upon the excitation of perylene-diimide subunit (λ=491 nm) relaxed via a charge-separation mediate species to [H22+TrPP-MDPTCDI*], which decayed with radiation of protonated free-base porpyrin; the latter course was accompanied with a low efficiency energy transfer from perylene-diimide to the protonated free-base porphyrin subunit.

Key words: Protonation, Molecular array, Charge transfer, Energy transfer, Excited states

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