Supramolecular Photoinduced Electron Transfer between a Redox‐Active Hexanuclear Metal–Organic Cylinder and an Encapsulated Ruthenium(II) Complex

Abstract

By using redox-active nickel(II) ions as the connect nodes, a hexanuclear metal-organic cylinder (Ni-YL) was achieved through self-assembly with a large cavity and an opening windows capable to accommodate guest molecules. The suitable cavity of Ni-YL provides an opportunity to encapsulate the anionic ruthenium bipyridine derivative [Ru(dcbpy)3] (dcbpy=2,2'-bipyridine-4,4'-dicarboxylic acid) as the photosensitizer for light-driven reactions. The host-guest behavior between Ni-YL and [Ru(dcbpy)3] was investigated by mass spectrometry, NMR spectroscopy, and computational studies, revealing an effective binding of the guest [Ru(dcbpy)3] within the cavity of Ni-YL. Optical experiments suggested a pseudo-intramolecular photoinduced electron transfer (PET) process between the [Ru(dcbpy)3] and the host Ni-YL, leading to an efficient light-driven hydrogen production based on this system. Control experiments with a mononuclear Ni complex as a reference photocatalyst and the inactive [Fe(dcbpy)3] as an inhibitor for comparison were also performed to confirm such a supramolecular photocatalysis process.

Photochemical Properties of Host–Guest Supramolecular Systems with Structurally Confined Metal–Organic Capsules

“…to encapsulate an anionic ruthenium polypyridyl photosensitizer Ru(dcbpy) 3 (dcbpy = 2,2′-bipyridine-4,4′-dicarboxylic acid). 41 This resulted a pseudointramolecular photoinduced electron transfer process between the [Ru(dcbpy) 3 ] unit and the host H22, leading to an efficient light-driven hydrogen production based on this system. The new, well-elucidated reaction pathways and the increased molarity of the reaction within the confined space render these supramolecular systems superior to other relevant systems.…”

Strong Co-Ion Effect via Cation−π Interaction on the Self-Assembly of Metal–Organic Cationic Macrocycles

“…Metal–organic macrocycles are constructed by coordination bonds between predesigned organic ligands and selected metal ions, which have potential applications in many areas such as chemical sensing, molecular recognition, reactive intermedia isolation, and catalysis . Owing to their versatile structures, it is possible to construct an electron-rich cavity with bunch of aromatic groups, which shows structural similarities with the above-mentioned artificial cation receptors . Therefore, it is interesting to see whether the solution behaviors of MOM macroion could be obviously affected by the cationic co-ions through the relatively strong cation−π interaction.…”

Photoinduced Electron Transfer Process Visualized on Single Silver Nanoparticles

“…Photoinduced electron transfer (PET), a common form of photoelectric conversion widely applied in solar energy materials, − fluorescent sensors, and fluorescent switches, has been extensively investigated in chemistry, physics, and biology due to the fundamental interest in the excited states of organic molecules. − However, visualizing the PET process, which can reveal the reaction mechanisms involving the electron transfer information between reactants and thus improve the photoelectric conversion efficiency, or design more efficient PET sensors and switches, still remains a big challenge.…”