Photoinduced hydrogen evolution in supramolecular devices with a rhenium photosensitizer linked to FeFe-hydrogenase model complexes

Abstract

Coordination of the pyridyl-attached diiron azadithiolate hexacarbonyl complexes (2 and 3) through the pyridyl nitrogen to the Re on 10-phenanthroline rhenium (5a) and 2,9-diphenyl-1,10-phenanthroline rhenium (5b) forms novel [Re-Fe] complexes 7a, 7b and 8 respectively. Under visible light illumination using triethylamine as a sacrificial electron donor and [Re-Fe] type complexes (7a, 7b or 8) as catalysts, remarkably increased efficiency was observed for photoinduced hydrogen production with a turnover number reaching 11.8 from complex 7a and 8.75 from 7b. To the best of our knowledge, these are the best values compared to other [Re-Fe] photocatalysts reported so far. In contrast to the parent molecules, the turnover number by the intermolecular combination of complexes 6a and 2 showed a value of 5.23, and that from 6b and 2 is 3.8, while no H(2) was detected from 8a and 3 under the same experimental conditions. Obviously, the intramolecular combination of rhenium(I) and [2Fe2S] as a catalyst is promising for efficient H(2) evolution, and it is better than the intermolecular multi-component system.

Photocatalytic Hydrogen Evolution Driven by [FeFe] Hydrogenase Models Tethered to Fluorene and Silafluorene Sensitizers

“…Progressive addition of TEA to a solution of compound 2 quenched the luminescence with a rate constant K SV =21.54±0.59 m −1 for 2 (27 μ m in acetonitrile) at an excitation wavelength of λ ex =245 nm. Similar results were obtained for compound 3 (27 μ m in MeCN) with K SV =10.28±0.14 m −1 at λ ex =247 nm and compound 4 (27 μ m in MeCN) with K SV =4.36±0.10 m −1 at λ ex =256 nm ( K SV =80.0±2.2 m −1 for 1 , 27 μ m in MeCN, excitation at 255 nm) . The decrease in the emission intensity at λ max (Figures S10–S12 in the Supporting Information) under these conditions is reasonable as TEA acts as a sacrificial electron donor to fill the hole generated in the π‐orbital (S 0 state) upon photoexcitation.…”

“…Multicomponent systems with commonly used organometallic photosensitizers of either Ru, Re, Rh, or Ir have been reported . For some sensitizer–catalyst dyads, in which a light harvester is covalently linked to a [FeFe]‐H 2 ase mimic, photocatalysis has been shown to be driven at moderate turnover numbers (TON<127) . Furthermore, complete hybrid artificial photosynthetic systems, dendrimer‐based systems, ZnS nanoparticles, or quantum dots, as light harvesters have also been reported.…”

“…[17][18][19][20][21][22][23][24] For some sensitizer-catalyst dyads, in whichalight harvester is covalently linked to a[ FeFe]-H 2 ase mimic, photocatalysis has been shown to be driven at moderate turnover numbers (TON < 127). [25][26][27][28][29][30] Furthermore, complete hybrida rtificial photosynthetic systems, [31] dendrimer-based systems, [32] ZnS nanoparticles, [33] or quantum dots, [34,35] as light harvesters have also been reported. More recently,a nu nsensitized protonated model capable of absorbingl ight energy and catalyzing H 2 formation has been characterized.…”

A Silicon‐Heteroaromatic System as Photosensitizer for Light‐Driven Hydrogen Production by Hydrogenase Mimics

“…Multicomponent systems containing a surplus of ruthenium photosensitizers or organic fluorophores and [2Fe2S] clusters were investigated and showed moderate H 2 development upon irradiation with light. [19] Furthermore, supramolecular assemblies comprising [2Fe2S] model compounds with an InP nanophotocathode, [20] ZnS nanoparticles, [21] multichromophoric hexad self-assemblies, [22] or Mn 2 Ru complexes [23] as light-harvesting molecules were reported. [12][13][14][15][16][17][18] These complexes revealed low turnover numbers (TON Ͻ 0.15) for H 2 generation.…”

Underestimated Potential of Organometallic Rhenium Complexes as Anticancer Agents

“…The type II reaction is defined as generation of singlet oxygen via PS-oxygen interaction. 83 Although many more Re compounds have been identified as efficient triplet photosensitizers, 39,[84][85][86][87][88] this property has been more applied in photo-catalysis than in anti-cancer drug development.…”