In this work we report on the influence of the polarity of the environment on the optical properties of octa-α-butyloxy-H2phthalocyanine ( H 2 PC ( OBu )8) in organic solvents and liposomes using steady-state absorption as well as time correlated single photon counting (TCSPC). A change was found in Q-band absorption in various solvents. Taking into account that the absorption properties of H 2 PC ( OBu )8 are modulated by the polarity of the direct surrounding, polarities inside micro-heterogeneous systems can be probed. This was demonstrated for liposomes of dipalmitoylphosphatidylcholine (DPPC), with regard to the behavior during the phase transition between the gel and liquid-crystal state. Absorption spectra of H 2 PC ( OBu )8 embedded in DPPC-liposomes have been recorded in the temperature range from 15 to 70 °C, covering the phase transition region at about 36–39 °C. The Q-band absorption at temperatures below and above the phase transition resembles those in polar and non-polar solvents, respectively. Measurements of fluorescence lifetime confirm this equivalence. We explain this behavior by a change of the localization of the dye molecules inside the membrane. For H 2 PC ( OBu )8 embedded in DPPC-liposomes we demonstrated by using optical methods that the position of the dye molecules strongly depends on the phase-state of the phospholipid. In addition, H 2 PC ( OBu )8 can be used as a probe for phase transition processes taking advantage of the specific behavior in surroundings with different polarity.

中文翻译：

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利用八-α-丁氧基-H2酞菁的特殊光学性质观察磷脂脂质体的相变

在这项工作中，我们报告了环境极性对八-α-丁氧基-H 光学性质的影响2酞菁（H2个人电脑（欧布）8) 在有机溶剂和脂质体中使用稳态吸收以及时间相关单光子计数 (TCSPC)。在各种溶剂中发现 Q 波段吸收发生变化。考虑到 H 的吸收特性2个人电脑（欧布）8由直接周围的极性调制，可以探测微异质系统内部的极性。这在二棕榈酰磷脂酰胆碱 (DPPC) 脂质体的凝胶和液晶状态之间的相变期间的行为方面得到了证实。H的吸收光谱2个人电脑（欧布）8嵌入 DPPC 脂质体的温度范围为 15 至 70°C，覆盖约 36-39°C 的相变区域。低于和高于相变温度的 Q 波段吸收分别类似于极性和非极性溶剂中的吸收。荧光寿命的测量证实了这种等效性。我们通过改变膜内染料分子的定位来解释这种行为。对于 H2个人电脑（欧布）8嵌入 DPPC 脂质体中，我们通过使用光学方法证明染料分子的位置强烈依赖于磷脂的相态。此外，H2个人电脑（欧布）8利用不同极性环境中的特定行为，可用作相变过程的探针。