Synthesis and Characterization of a Ruthenium(II) Complex for the Development of Supramolecular Photocatalysts Containing Multidentate Coordination Spheres

Abstract

The synthesis of the new bis‐heteroleptic RuII complex [(tbbpy)2Ru(dptpphz)](PF6)2 (7), that exhibits a tetradentate coordination sphere for a second metal centre, and its characterization are presented. The complex shows similar photostability and redox properties regarding the first ligand‐centred reductions compared to its tpphz analogue. Concentration‐dependent NMR investigations were performed and a dimerization constant (KD = 83 ± 5) could be calculated, which was significantly lower than that of other tpphz systems. Photophysical investigations reveal a stabilizing effect of the two electron‐withdrawing 2‐pyridyl substituents on π–π* transition of the phenazine sphere. The typical H2O‐induced light‐switch effects have also been observed. To further highlight the potential of the tetradentate coordination site, the ZnII adduct of 7 was prepared and preliminary studied.

Electron Storage Capability and Singlet Oxygen Productivity of a RuII Photosensitizer Containing a Fused Naphthaloylenebenzene Moiety at the 1,10‐Phenanthroline Ligand

“…According to literature protocols, ad imerization constant of 27 m À1 was determined for Rubiipo (see Supporting Information). [43][44][45][46] This clearly suggests intermolecular interactions between different Rubiipo species in solution, which are caused by the quite large and planar biipo ligand. This observation is in line with other Ru II complexes bearingp olycyclic diimine ligandss uch as dipyridophenazine,t etrapyridophenazine (dimerization constant = 289 AE 17 m À1 ), di(pyridin2-yl)tetraazaphenazine (83 AE 17 m À1 )o rt etraazatetra-pyridopentacene,w hich reveal even stronger interactions between the extended p-systems of these ligands.…”

“…This observation is in line with other Ru II complexes bearingp olycyclic diimine ligandss uch as dipyridophenazine,t etrapyridophenazine (dimerization constant = 289 AE 17 m À1 ), di(pyridin2-yl)tetraazaphenazine (83 AE 17 m À1 )o rt etraazatetra-pyridopentacene,w hich reveal even stronger interactions between the extended p-systems of these ligands. [26,27,29,45,46] This might be important,b ecause in case of high intermoleculara ssociation behavior self-quenching of excited states can get more favorable. [29,[47][48][49] Single crystals of Rubiipo suitable for X-ray diffraction analysis were obtained by slow evaporation from as aturated acetonitrile/water mixture.…”

Promising sensitizers for dye sensitized solar cells: A comparison of Ru(II) with other earth's scarce and abundant metal polypyridine complexes

“…Several studies on different metal‐centered polypyridyl based dyes for effective DSSC on NiO‐based SCs have been performed during the last few years. Rau et al studied several ruthenium‐based bipyridine complexes for the photocatalytic oxidation of water involving different metal centers such as Pt, Pd, Ag . Recently, Rau et al also conveyed that polypyridyl complexes combined with different metals like osmium or iridium, other than ruthenium, also show vast applications in the field of photochemistry .…”

“…Rau et al studied several ruthenium-based bipyridine complexes for the photocatalytic oxidation of water involving different metal centers such as Pt, Pd, Ag. [23][24][25][26] Recently, Rau et al also conveyed that polypyridyl complexes combined with different metals like osmium or iridium, other than ruthenium, also show vast applications in the field of photochemistry. [27,28] Furthermore, in 2017, Rau et al studied artificial photosynthesis using rhodium-based catalysts.…”

Stille Expands the Family: Access to 5,6‐Bis‐2‐thienyl‐Substituted Phenanthroline Under Mild Conditions for Luminescent Ruthenium Complexes

“…While a loss of absorptivity of 30 % and change in shape of the MLCT absorption could be observed over the first 5 hours of irradiation, only minor changes in the total absorption spectra of 3 could be detected for the rest of the time. Compared to the reference complex [Ru(bpy) 3 ] 2+ , 3 showed a superior photostability as almost half of the reference molecules are usually decomposed within 24 h , …”