Relevance of the electron transfer pathway in photodynamic activity of Ru(ii) polypyridyl complexes containing 4,7-diphenyl-1,10-phenanthroline ligands under normoxic and hypoxic conditions

Abstract

The purpose of this study was to investigate a correlation between the spectroscopic and photophysical properties of Ru(II) polypyridyl complexes and their photodynamic activity in vitro. A series of Ru(II)...

Intraligand Excited States Turn a Ruthenium Oligothiophene Complex into a Light-Triggered Ubertoxin with Anticancer Effects in Extreme Hypoxia

“…Several studies have demonstrated this oxygen-independent photochemistry in hypoxia under cell-free conditions, ,− and examples of phototoxic responses toward cancer cells growing in hypoxia are starting to emerge. − Reliable strategies for maintaining hypoxia and assessing the dissolved oxygen concentration at the time of illumination have proven difficult but are now beginning to materialize, ,,− ,− making it possible to examine the potential of PCT agents as hypoxia-active phototherapeutics. In collaboration with the Glazer group, we published the most active PCT agent (at the time)with [Ru­(6,6′-dmb) 2 (1-NIP)]­Cl 2 and a phototherapeutic index (PI) of 15 (ratio of dark to light EC 50 values) at 1% O 2 using visible light, where 1-NIP is 2-(naphthalen-1-yl)-1 H -imidazo­[4,5- f ]­[1,10]­phenanthroline. , Bonnet and co-workers have since achieved a PI near 16 under 1% O 2 …”

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

“…In addition, PDT can induce hypoxia as oxygen is consumed during irradiation. , Decreased generation of ROS limits damage to cancerous cells. To address this, there is motivation to develop light-triggered compounds that exploit oxygen-independent mechanisms for phototoxicity. − In this context, metal complexes such as Ru(II) polypyridyl systems have attracted considerable attention. ,,,− Judicious choice of ligand–metal combinations provides access to a variety of excited-state configurations with characteristic photophysical properties and reactivities. Strategies have included photorelease of bulky ligands to reveal phototoxic metals and/or ligands, ,,,,,− photocaging of chemotherapeutics and enzyme inhibitors, ,,,,,− …”

Energy transfer in metal-exchange binuclear complexes covalently linked by asymmetric ligands

“…The potential luminescence of Ru(bpy)-based units did not exhibit any appreciable emission in complexes C5 and C6 , which was attributed to the intramolecular quenching of the Ru-bpy luminescence by the Os( ii ) center. 35,53 The above comparison suggested that the energy transfer occurred within the Os( ii )/Ru( ii ) binuclear complexes. 18,53,54 Φ c = ( I c / I s )( A c / A s )( η c 2 / η s 2 ) Φ s where c and s stand for the compounds of synthesized and standard complex, η is the refractive index of the solvent, A is the solution absorbance at the excitation wavelength ( λ ex ), I is the integrated emission intensity, and Φ s is the standard luminescence quantum yield of [Ru(bpy) 3 ] 2+ ( Φ = 0.06).…”

“…2, and the corresponding data are listed in Table 1. 35 Complexes C1 , C2 , C3 , and C4 presented three absorption bands, whereas C7 and C8 only showed two absorption bands. However, the heterometallic complexes C5 , C6 , C9 , and C10 exhibited four absorption bands in the range of 200–800 nm.…”

“…The potential luminescence of Ru(bpy)-based units did not exhibit any appreciable emission in complexes C5 and C6, which was attributed to the intramolecular quenching of the Ru-bpy luminescence by the Os(II) center. 35,53 The above comparison suggested that the energy transfer occurred within the Os(II)/ Ru(II) binuclear complexes. 18,53,54…”