Optimization of Triplet Excited State and Singlet Oxygen Quantum Yields of Picolylamine鈥揚orphyrin Conjugates through Zinc Insertion

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• 作者：Betsy Marydasan ; Akhil K. Nair ; Danaboyina Ramaiah
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：October 31, 2013
• 年：2013
• 卷：117
• 期：43
• 页码：13515-13522
• 全文大小：356K
• 年卷期：v.117,no.43(October 31, 2013)
• ISSN：1520-5207

文摘

We synthesized a new class of picolylamine鈥損orphyrin conjugates 1鈥?b>3 and have investigated the effect of heavy atom insertion on their intersystem crossing efficiency through spin鈥搊rbit 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鈥損orphyrin 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鈥損orphyrin 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.