As a novel rylene type dye a diimine ligand with a fully rigid and extended π‐system in its backbone was prepared by directly fusing a 1,10‐phenanthroline building block with 1,8‐naphthalimide. The corresponding heteroleptic ruthenium photosensitizer bearing one biipo and two tbbpy ligands was synthesized and extensively analyzed by a combination of NMR, single crystal X‐ray diffraction, steady‐state absorption and emission, time‐resolved spectroscopy and different electrochemical measurements supported by time‐dependent density functional theory calculations. The cyclic and differential pulse voltammograms revealed, that the naphthaloylenebenzene moiety enables an additional second reduction of the ligand. Moreover, this ligand possesses a very broad absorption in the visible region. In the RuII complex this causes an overlap of ligand‐centered and metal‐to‐ligand charge transfer transitions. The emission of the complex is clearly redshifted compared to the ligand emission with very long‐lived excited states lifetimes of 1.7 and 24.7 μs in oxygen‐free acetonitrile solution. This behavior is accompanied by a surprisingly high oxygen sensitivity. Finally, this photosensitizer was successfully applied for the effective evolution of singlet oxygen challenging some of the common RuII prototype complexes.

The Stille coupling method was used to functionalize the 5‐ and 6‐positions of 1,10‐phenanthroline with thiophene substituents. Photophysical investigations of 5,6‐bis(5‐methylthien‐2‐yl)‐1,10‐phenanthroline showed a marked influence of the substituents on the absorption properties, as a bathochromic shift of 50 nm regarding the π–π* transitions was observed. The contribution of the substituents in the corresponding Ru complex, in turn, was negligible on the absorption properties of the compound, while the extinction coefficient for the complex dropped by a factor of 0.5 compared to reference complexes. Structural investigation of the ligand and the complex revealed a perpendicular orientation of the thiophene groups with respect to the phenanthroline plane, while no preferred conformation of sulfur atoms (parallel or antiparallel) could be observed. The newly synthesized complex exhibits a superior photostability relative to [Ru(bpy)3]2+, which is promising for future applications.

This contribution describest he 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 ac andidate for photodynamic therapy in the biological red/NIR window. The complex is takenu pb yMCF7 cells andl ocalizes rather homogeneously within in the cytoplasm. To detail the sub-ns photophysics of 1,c omparativet ransienta bsorptionm easurements were carried out in different solvents to derive am odel of the photoinduced processes. Key to rationalize the excited-state relaxationis al onglived 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 overallm odel remained the same, the excited-state dynamics are affectedstrongly by the intracellular environment. Our study represents the first in depth correlation towards ex-vivo and in vivo ultrafast spectroscopy for apossible photodrug.

Multichromophoric systems based on a Ru II polypyridine moiety containing an additional organic chromophore are of increasing interest with respect to different lightdriven applications. Here, we present the synthesis and detailed characterization of a novel Ru II photosensitizer, namely [(tbbpy) 2 Ru((2-(perylen-3-yl)-1H-imidazo[4,5-f][1,10]phenanthrolline))](PF 6 ) 2 RuipPer, that includes a merged perylene dye in the back of the ip ligand. This complex features two emissive excited states as well as a long-lived (8 μs) dark state in acetonitrile solution. Compared to prototype [(bpy) 3 Ru] 2 + -like complexes, a strongly altered absorption (ɛ = 50.3 × 10 3 M À 1 cm À 1 at 467 nm) and emission behavior caused by the introduction of the perylene unit is found. A combination of spectro-electrochemistry and timeresolved spectroscopy was used to elucidate the nature of the excited states. Finally, this photosensitizer was successfully used for the efficient formation of reactive singlet oxygen.

Two are better than one: In a joint study, groups in two laboratories at TU Braunschweig and Ulm University present a novel bichromophoric RuII complex. This unique photosensitizer was obtained by fusing a ruthenium polypyridine chromophore with an additional perylene dye. This photosensitizer exhibits a strong absorptivity in the visible region and an enhanced excited state lifetime of 8 μs. In addition, this complex enables the efficient production of singlet oxygen. More information can be found in the Research Article by S. Rau, S. Tschierlei, et al. (DOI: 10.1002/chem.202103609).