Photosciences and Photonics, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST) , Trivandrum 695019, India.
J Phys Chem B. 2013 Oct 31;117(43):13515-22. doi: 10.1021/jp407524w. Epub 2013 Oct 10.
We synthesized a new class of picolylamine-porphyrin conjugates 1-3 and have investigated the effect of heavy atom insertion on their intersystem crossing efficiency through spin-orbit perturbations. By incorporating zinc ions in the core as well as periphery positions of the porphyrin ring, we have successfully optimized their triplet excited state quantum yields and their efficiency to generate singlet oxygen. Uniquely, the picolylamine-porphyrin conjugate 3 having five zinc ions exhibited a triplet excited state quantum yield of ca. 0.97 and a sensitized singlet oxygen generation yield of ca. 0.92. In contrast, the free base porphyrin derivative 1 exhibited ca. 0.64 and 0.5 of the triplet excited state and singlet oxygen quantum yields, respectively. Our results demonstrate that the insertion of zinc metal ions in the picolylamine-porphyrin conjugates not only quantitatively enhances the triplet excited state and singlet oxygen yields but also imparts hydrophilicity, thereby their potential use as sensitizers in photodynamic therapy and green photooxygenation reactions.
我们合成了一类新的吡啶基卟啉缀合物 1-3，并通过自旋轨道微扰研究了重原子插入对它们的系间窜越效率的影响。通过在卟啉环的核心和外围位置引入锌离子，我们成功优化了它们的三重激发态量子产率和生成单线态氧的效率。独特的是，具有五个锌离子的吡啶基卟啉缀合物 3 表现出约 0.97 的三重激发态量子产率和约 0.92 的敏化单线态氧生成产率。相比之下，自由碱基卟啉衍生物 1 分别表现出约 0.64 和 0.5 的三重激发态和单线态氧量子产率。我们的结果表明，吡啶基卟啉缀合物中锌金属离子的插入不仅定量增强了三重激发态和单线态氧的产率，而且赋予了其亲水性，从而使其有可能作为光动力治疗和绿色光氧化反应中的敏化剂。
