Ru(II) Phenanthroline-Based Oligothienyl Complexes as Phototherapy Agents

Ru(II) Oligothienyl Complexes with Fluorinated Ligands: Photophysical, Electrochemical, and Photobiological Properties

“…These 3 MLCT energies are lower (by ∼0.2 to 0.3 eV) than those for related Ru(II) polypyridyl systems without substituted ligands due to the electron-withdrawing groups of the 4,4′-btfmb coligands in this series. These groups do not impact the 3 ILCT/ 3 LLCT/ 3 IL energies, which are very similar to those computed for the related series with 1,10-phenanthroline (phen) coligands . However, the lower 3 MLCT energies in the Ru(II) 4,4′-btfmb complexes result in an 3 MLCT-based T 1 for Ru-2T (rather than the IP- n T-based triplet that tends to be T 1 in other related families).…”

“…The mixed 3 ILCT/ 3 LLCT/ 3 IL states that are T 1 in the case of Ru-3T and Ru-4T have computed adiabatic energies of 1.54 and 1.42 eV, respectively. The drop in energy of the T 1 state for Ru-3T and Ru-4T is directly related to its organic 3 ILCT character and length of the n T chain as we have seen previously. , …”

“…The lowest-energy singlet–singlet transition is mixed 1 MLCT/ 1 LLCT for Ru-2T wherein 1 LLCT involves n T → 4,4′-btfmb CT, while these transitions are mixed 1 LLCT/ 1 IL/ 1 ILCT and 1 LLCT/ 1 ILCT/ 1 IL for Ru-3T and Ru-4T , respectively. In these cases, 1 LLCT is the major contributor and involves n T → IP CT, 1 ILCT involves n T → n T CT, and 1 IL involves localized ππ* transitions within n T. These mixed transitions shift to longer wavelengths and increase in 1 ILCT character with increasing n as we have observed previously in related compounds. ,,,, …”

“…To expand our understanding of oligothiophene-containing coordination complexes, we are examining variations in their central metals, coordinating ligands, thienyl groups, counterions, and coordination geometries. ,,,,,− We aim to establish structure–activity relationships (SARs) for medicinally active complexes that reconcile their physicochemical, photophysical, electrochemical, and biological properties with the ideal phototherapy profile for a given clinical setting. In this study we introduce a series of Ru­(II) PSs ( Ru- n T ), each featuring two 4,4′-bis­(trifluoromethyl)-2,2′-bipyridine (4,4′-btfmb) coligands and a thienyl-containing imidazo­[4,5- f ]­[1,10]­phenanthroline (IP- n T) ligand with n = 1–4 thiophene rings.…”

Controlling Excited State Localization in Bichromophoric Photosensitizers via the Bridging Group

“…Similarly, a study by Wenger and co-workers showed that naphthalene was able to function as a triplet reservoir in an Ir­(III) complex, leading to lifetimes of 72.1 μs . Excited state lifetimes may also be increased through the formation of intraligand charge-transfer (ILCT) states, which involve incorporation of an organic-based donor substituent. − …”