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Intracellular Photophysics of an Osmium Complex bearing an Oligothiophene Extended Ligand
Author(s) -
Schneider Kilian R. A.,
Chettri Avinash,
Cole Houston D.,
Reglinski Katharina,
Brückmann Jannik,
Roque John A.,
Stumper Anne,
Nauroozi Djawed,
Schmid Sylvia,
Lagerholm Christoffer B.,
Rau Sven,
Bäuerle Peter,
Eggeling Christian,
Cameron Colin G.,
McFarland Sherri A.,
Dietzek Benjamin
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202002667
Subject(s) - excited state , intracellular , relaxation (psychology) , chemistry , ultrafast laser spectroscopy , ligand (biochemistry) , osmium , photochemistry , bipyridine , spectroscopy , biophysics , crystallography , receptor , biochemistry , ruthenium , biology , atomic physics , physics , catalysis , quantum mechanics , neuroscience , crystal structure
This contribution describes the excited‐state properties of an Osmium‐complex when taken up into human cells. The complex 1 [Os(bpy) 2 (IP‐4T)](PF 6 ) 2 with bpy=2,2′‐bipyridine and IP‐4T=2‐{5′‐[3′,4′‐diethyl‐(2,2′‐bithien‐5‐yl)]‐3,4‐diethyl‐2,2′‐bithiophene}imidazo[4,5‐ f ][1,10]phenanthroline) can be discussed as a candidate for photodynamic therapy in the biological red/NIR window. The complex is taken up by MCF7 cells and localizes rather homogeneously within in the cytoplasm. To detail the sub‐ns photophysics of 1 , comparative transient absorption measurements were carried out in different solvents to derive a model of the photoinduced processes. Key to rationalize the excited‐state relaxation is a long‐lived 3 ILCT state associated with the oligothiophene chain. This model was then tested with the complex internalized into MCF7 cells, since the intracellular environment has long been suspected to take big influence on the excited state properties. In our study of 1 in cells, we were able to show that, though the overall model remained the same, the excited‐state dynamics are affected strongly by the intracellular environment. Our study represents the first in depth correlation towards ex‐vivo and in vivo ultrafast spectroscopy for a possible photodrug.