Synthesis and characterization of an immobilizable photochemical molecular device for H₂-generation

Abstract

With [Ru(II)(bpyMeP)2tpphzPtCl2](2+) (4) a molecular photocatalyst has been synthesized for visible-light-driven H2-evolution. It contains the ligand bpyMeP (4,4'-bis(diethyl-(methylene)-phosphonate)-2,2'-bipyridine) with phosphate ester groups as precursors for the highly potent phosphonate anchoring groups, which can be utilized for immobilization of the catalyst on metal-oxide semiconductor surfaces. The synthesis was optimized with regard to high yields, bpyMeP was fully characterized and a solid-state structure could be obtained. Photophysical studies showed that the photophysical properties and the localization of the excited states are not altered compared to similar Ru-complexes without anchoring group precursors. (4) was even more active in homogenous catalysis experiments than [Ru(II)(tbbpy)2tpphzPtCl2](2+) (6) with tbbpy (4,4'-bis(tbutyl)-2,2'-bipyridine) as peripheral ligands. After hydrolysis (4) was successfully immobilized on NiO, suggesting that an application in photoelectrosynthesis cells is feasible.

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 .…”

Modular Synthesis of Elongated Phosphonate Bipyridines

“…[29] 4,4Ј-Bis(hydroxymethylphenyl)-2,2Ј-bipyridine (1): This compound was prepared by a modified literature procedure. [29] 4,4Ј-Bis(hydroxymethylphenyl)-2,2Ј-bipyridine (1): This compound was prepared by a modified literature procedure.…”

“…[31] The bipyridine 1 (0.65 g, 1.76 mmol) was dissolved in a mixture of 48 % HBr (165 mL) and concentrated sulfuric acid (61 mL). [29] A chloroform (3 mL) solution of 2 (130 mg, 0.26 mmol) and triethyl phosphite (4 mL) was refluxed for 20 h under argon. The pH was adjusted to neutral with conc.…”

“…Organicsoluble dialkyl phosphonates are useful coupling agent alternatives to phosphonic acids, which are often difficult to solubilize and must be generated under harsh conditions from the corresponding ester. [29] Generally, for a more chemically stable linkage between dye and semiconductor, both positions 4 and 4Ј of the bpy should be equipped with anchoring groups. In studies of dyes attached through flexible saturated linkers, it has been observed that the electronic coupling is weakened, and that charge carrier injection rates slow down with increased bridge length.…”

Mono- and Dual-modified Titania with a Ruthenium(II) Complex and Silver Nanoparticles for Photocatalytic Degradation of Organic Compounds

“…300 m 2 g -1 ) was used as received. Ru II CP2 (Figure 1a): [Ru(tbbpy) 2 (4,4′-(CH 2 PO 3 H 2 ) 2 bpy)] 2+ was synthesized according to an analogous complex in the literature (28). Water for solution preparation and sample washing was from a Milli-Q purification system.…”