Microenvironment-switchable singlet oxygen generation by axially-coordinated hydrophilic ruthenium phthalocyanine dendrimers
Microenvironment-switchable singlet oxygen generation by axially-coordinated hydrophilic ruthenium phthalocyanine dendrimers
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DOI：
10.1039/c0cp01015d
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发表时间：
2011-01-01
影响因子：
3.3
通讯作者：
Torres, Tomas
中科院分区：
文献类型：
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作者：
Hahn, Uwe;Setaro, Francesca;Torres, Tomas
在酞菁钌核周围制备了一系列新的金属枝状大分子。采用会聚合成策略，制备了含吡啶的配体，并通过配体轴向配位将其组装到酞菁钌上。在亲脂核心周围生长的低聚乙二醇链壳允许在水中溶解。光物理研究表明，所有的金属树状大分子都具有强磷光，其三重态的失活途径取决于化合物溶解的介质。一方面，枝晶壳对三重态的猝灭作用在水介质中得到了显著增强。另一方面，树突分子保护酞菁不受氧气的侵害。尽管如此，酞菁能够在极性较低的环境中产生单线态氧，例如在CHCl3或THF溶液中，而在水中，单线态氧的产生几乎完全关闭。
A series of new metallodendrimers built around a ruthenium phthalocyanine core has been prepared. Employing a convergent synthetic strategy, pyridine-containing ligands were prepared and then assembled onto the ruthenium phthalocyanine through axial ligand coordination. The growing shell of oligoethylene glycol chains surrounding the lipophilic core allows solubilisation in water. Photophysical studies show that all the metallodendrimers are strongly phosphorescent and the deactivation pathway of their triplet state depends on the medium in which the compounds are dissolved. On one hand, quenching of the triplet state by the dendritic shell is observed and found to be substantially enhanced in aqueous media. On the other, the dendrimer shields the phthalocyanine from oxygen. This notwithstanding, the phthalocyanines are able to generate singlet oxygen in less polar environments such as in CHCl3 or THF solution, while in water the generation of singlet oxygen is almost completely switched off.