Increasing the efficiency of molecular artificial photosynthetic systems is mandatory for the construction of functional devices for solar fuel production. Decoupling the light-induced charge separation steps from the catalytic process is a promising strategy, which can be achieved thanks to the introduction of suitable electron relay units performing charge accumulation. We report here on a novel ruthenium tris-diimine complex able to temporarily store two electrons on a fused dipyridophenazine–pyridoquinolinone π-extended ligand upon visible-light irradiation in the presence of a sacrificial electron donor. Full characterization of this compound and of its singly and doubly reduced derivatives thanks to resonance Raman, EPR and (TD)DFT studies allowed us to localize the two electron-storage sites and to relate charge photoaccumulation with proton-coupled electron transfer processes.

中文翻译：

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用于在稠合联吡啶吩嗪 (dppz)–吡啶并喹啉酮配体上光积聚两个电子的人工光合系统†

提高分子人工光合作用系统的效率对于构建太阳能燃料生产的功能装置是强制性的。将光诱导的电荷分离步骤与催化过程分离是一种有前途的策略，这可以通过引入执行电荷积累的合适电子中继单元来实现。我们在这里报告了一种新型钌三二亚胺络合物，在牺牲电子供体存在的情况下，在可见光照射下，能够在稠合的二吡啶吩嗪-吡啶并喹啉酮π-延伸配体上暂时存储两个电子。通过共振拉曼、EPR 和 (TD)DFT 研究，对该化合物及其单还原和双还原衍生物的全面表征使我们能够定位两个电子存储位点，并将电荷光累积与质子耦合电子转移过程联系起来。