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首页> 外文期刊>Chemistry: A European journal >Dendritic Polyglutamic Porphyrins: Probing Porphyrin Protection by Oxygen-Dependent Quenching of Phosphorescence
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Dendritic Polyglutamic Porphyrins: Probing Porphyrin Protection by Oxygen-Dependent Quenching of Phosphorescence

机译：树突状多谷氨酸卟啉：通过氧依赖性的磷光猝灭来探究卟啉的保护

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摘要

A series of dendritic polyglutamic Pd porphyrins with a Pd-meso-tetra-4-carboxyphenylporphyrin (PdTCPP) core was synthesized by the divergent growth approach. The synthesized compounds are described by the general formula PdPorphGlu~NOR, where N=1-4 (dendrimer generation), Glu=glutamate layer, and R is the terminal group=H, All (allyl), Et, or Bz. Additionally, 11-aminoundecanoic acid (AUDA) was added to the periphery of PdPorphGlu~1OH to give PdPorphGlu~1AUDAOH, which was, in turn modified with another layer of glutamates to give the pseudodendrimer PdPorphGlu~1AUDAGlu~1OH. All the synthesized compounds phosphoresce strongly with #gamma#_(max)=690 nm and lifetimes in the range of 0.5-1 ms in deoxygenated solutions. The observed phosphorescence is quenched by O_2, and the corresponding Stern-Volmer plots have been determined for the series for synthesized compounds in DMF and H_2O solutions. In DMF there was almost no difference in the quenching constants (K_q) for all the synthesized compounds; however, in water the values of K_q decreased significantly as the size of the dendrimers increased. We suggest that, depending on the solvent properties, the polyglutamic branches adopt either open or compact conformations. This alters the barrier to oxygen diffusion towards the porphyrin core.
机译：通过发散生长法合成了一系列具有Pd-间-四-4-羧基苯基卟啉（PdTCPP）核的树突状多谷氨酸Pd卟啉。合成的化合物由通式PdPorphGlu_NOR描述，其中N = 1-4（树状聚合物生成），Glu =谷氨酸层，R为端基= H，所有（烯丙基），Et或Bz。另外，将11-氨基十一烷酸（AUDA）添加至PdPorphGlu-1OH的外围以得到PdPorphGlu-1AUDAOH，其随后被另一层谷氨酸改性以得到假树状聚合物PdPorphGlu-1AUDAGlu-1OH。所有合成的化合物在脱氧溶液中均具有#gamma_（max）= 690 nm的强烈磷光性，寿命在0.5-1 ms范围内。观察到的磷光被O_2淬灭，并确定了DMF和H_2O溶液中合成化合物系列的相应Stern-Volmer图。在DMF中，所有合成化合物的猝灭常数（K_q）几乎没有差异;然而，在水中，随着树枝状聚合物尺寸的增加，K_q值显着下降。我们建议根据溶剂的性质，聚谷氨酸支链采用开放或紧密构象。这改变了氧向卟啉核扩散的屏障。

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