Bio-inspired, side-on attachment of a ruthenium photosensitizer to an iron hydrogenase active site model.
The first ruthenium-diiron complex [(mu-pdt)Fe2(CO)5{PPh2(C6H4CCbpy)}Ru(bpy)2]2+ 1 (pdt = propyldithiolate, bpy = 2,2'-bipyridine) is described in which the photoactive ruthenium trisbipyridyl unit is linked to a model of the iron hydrogenase active site by a ligand directly attached to one of the iron centers. Electrochemical and photophysical studies show that the light-induced MLCT excited state of the title complex is localized towards the potential diiron acceptor unit. However, the relatively mild potential required for the reduction of the acetylenic bipyridine together with the easily oxidized diiron portion leads to a reductive quenching of the excited state, instead. This process results in a transiently oxidized diiron unit which may explain the surprisingly high light sensitivity of complex 1.
Ekström
Jesper
J
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691, Stockholm, Sweden.
Abrahamsson
Maria
M
Olson
Carol
C
Bergquist
Jonas
J
Kaynak
Filiz B
FB
Eriksson
Lars
L
Sun
Licheng
L
Becker
Hans-Christian
HC
Akermark
Björn
B
Hammarström
Leif
L
Ott
Sascha
S
D001665:Binding Sites; D004563:Electrochemistry; D006864:Hydrogenase / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010777:Photochemistry; D017319:Photosensitizing Agents / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
D007506:Iron-Sulfur Proteins; D008024:Ligands; D017319:Photosensitizing Agents; D012428:Ruthenium; C118830:iron hydrogenase; D006864:Hydrogenase