Chemistry Department & Center of Instrumental Analysis, Hebei Normal University of Science and Technology, Qinhuangdao, Hebei Province, China.
J Phys Chem B. 2013 May 9;117(18):5533-9. doi: 10.1021/jp4013812. Epub 2013 Apr 26.
The excited triplet-, singlet-, and ground-state properties as well as singlet oxygen generation capability of four brominated BODIPY dyes were measured in toluene with laser flash photolysis, fluorescence spectroscopy, time-correlated single-photon counting, and absorption spectroscopy. The triplet-triplet (T1-Tn) absorption spectra were identified for four dyes 1B, 2B, 4B, and 6B substituted with one, two, four, and six Br atoms, respectively. The triplet quantum yield (ΦT) of a usual BODIPY dye is negligible and has rarely been studied. So is the case for the parent compound 0B (8-phenyl boron-dipyrromethene), in which no Br atom is present. The substitution of the first Br atom into the π ring of BODIPY allowed a dramatic increase of ΦT from 0.0 of 0B to 0.39 for 1B. The further addition of Br number increased ΦT to 0.46, 0.50, and 0.66 for 2B, 4B, and 6B, respectively. The triplet lifetimes τT are also fairly long, which is 43, 39, 36, and 26 μs, for 1B, 2B, 4B, and 6B, respectively. The brominated BODIPY dyes are therefore efficient singlet oxygen photosensitizers with the formation quantum yield of 0.39, 0.45, 0.49, and 0.64 for 1B, 2B, 4B, and 6B, respectively. The result indicates their potential application in photodynamic therapy of cancer. The fluorescence properties of the dyes were also measured.
用激光闪光光解、荧光光谱、时间相关单光子计数和吸收光谱法测量了四种溴化 BODIPY 染料的三重态、单重态和基态性质以及单线态氧生成能力。四种染料 1B、2B、4B 和 6B 分别用一个、两个、四个和六个 Br 原子取代，确定了它们的三重态-三重态（T1-Tn）吸收光谱。通常的 BODIPY 染料的三重态量子产率（ΦT）可忽略不计，且很少对其进行研究。同样，在没有 Br 原子的母体化合物 0B（8-苯基硼二吡咯甲烷）中也是如此。BODIPY 的π 环中第一个 Br 原子的取代使得 ΦT 从 0B 的 0 显著增加到 1B 的 0.39。进一步增加 Br 原子的数量将 ΦT 分别增加到 0.46、0.50 和 0.66，对于 2B、4B 和 6B 而言。三重态寿命 τT 也相当长，分别为 43、39、36 和 26 μs，对于 1B、2B、4B 和 6B 而言。因此，溴化 BODIPY 染料是有效的单线态氧光敏剂，其形成量子产率分别为 1B、2B、4B 和 6B 的 0.39、0.45、0.49 和 0.64。结果表明它们在癌症的光动力疗法中有潜在的应用。还测量了染料的荧光性质。
