The effect of peripheral bipyridine ligands on the photocatalytic hydrogen production activity of Ru/Pd catalysts

Abstract

A pyrazine bridged ruthenium/palladium bimetallic photocatalyst with peripheral 4,4'-dicarboxyethyl-2,2'-bipyridine ligands, EtOOC-RuPd, is reported, together with its 2,2'-bipyridine analogue. Upon irradiation with visible light, EtOOC-RuPd catalyses the production of hydrogen gas whereas the complex RuPd does not.

Palladium versus Platinum: The Metal in the Catalytic Center of a Molecular Photocatalyst Determines the Mechanism of the Hydrogen Production with Visible Light

“…Thecomparison of the 1 HNMR spectra of RuPd before and after the treatment with mercury reveals an extraction of the PdCl 2 catalytic center and the formation of the mononuclear Ru complex ( Figure S4). [20] Under identical conditions RuPt showed no reaction with mercury in acetonitrile.S ubsequently,t he activity of the photocatalysts in the light-driven hydrogen production under addition of elemental mercury was investigated. [20] Under identical conditions RuPt showed no reaction with mercury in acetonitrile.S ubsequently,t he activity of the photocatalysts in the light-driven hydrogen production under addition of elemental mercury was investigated.…”

Tuning of photocatalytic activity by creating a tridentate coordination sphere for palladium

“…As recently observed for a structurally related Ru-Pd photocatalysts, elemental Hg can decompose the photocatalyst already under non-catalytic conditions in pure acetonitrile. 51,52 Thus, prior to investigations under catalytic conditions, the effect of Hg on the photocatalysts was tested under non-reductive conditions. Therefore both catalysts were dissolved in pure acetonitrile, a drop of liquid Hg was added and the suspension was allowed to stir for 7 h under exclusion of light.…”

Optimization of Hydrogen‐Evolving Photochemical Molecular Devices

“…[12,13] These so called photochemical molecular devices (PMDs) combine the photocenter,the electron relay,and the catalytic center in one single molecule and offer the potential for as pecific modification of the single modules to optimize the PMDs efficiencya nd stability during catalysis.Aparticular example of this approach, which has been investigated in great detail, [14] is shown in Figure 1. It has become clear, however,t hat the design and optimization of such aPMD is by no means straight forward and it is surprising that, while extensive effort has been taken in the variation of the bridging [15] or peripheral ligands, [16,17] the structural features of the attached catalytic center have …”