Abstract |
We report new ruthenium complexes bearing the lipophilic bathophenanthroline (BPhen) ligand and dihydroxybipyridine (dhbp) ligands which differ in the placement of the OH groups ([(BPhen)2 Ru(n,n'-dhbp)]Cl2 with n = 6 and 4 in 1A and 2A , respectively). Full characterization data are reported for 1A and 2A and single crystal X-ray diffraction for 1A . Both 1A and 2A are diprotic acids. We have studied 1A , 1B , 2A , and 2B (B = deprotonated forms) by UV-vis spectroscopy and 1 photodissociates, but 2 is light stable. Luminescence studies reveal that the basic forms have lower energy 3 MLCT states relative to the acidic forms. Complexes 1A and 2A produce singlet oxygen with quantum yields of 0.05 and 0.68, respectively, in acetonitrile. Complexes 1 and 2 are both photocytotoxic toward breast cancer cells, with complex 2 showing EC50 light values as low as 0.50 μM with PI values as high as >200 vs. MCF7. Computational studies were used to predict the energies of the 3 MLCT and 3 MC states. An inaccessible 3 MC state for 2B suggests a rationale for why photodissociation does not occur with the 4,4'-dhbp ligand. Low dark toxicity combined with an accessible 3 MLCT state for 1 O2 generation explains the excellent photocytotoxicity of 2.
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Authors | Olaitan E Oladipupo, Spenser R Brown, Robert W Lamb, Jessica L Gray, Colin G Cameron, Alexa R DeRegnaucourt, Nicholas A Ward, James Fletcher Hall, Yifei Xu, Courtney M Petersen, Fengrui Qu, Ambar B Shrestha, Matthew K Thompson, Marco Bonizzoni, Charles Edwin Webster, Sherri A McFarland, Yonghyun Kim, Elizabeth T Papish |
Journal | Photochemistry and photobiology
(Photochem Photobiol)
Vol. 98
Issue 1
Pg. 102-116
(01 2022)
ISSN: 1751-1097 [Electronic] United States |
PMID | 34411308
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
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Copyright | © 2021 American Society for Photobiology. |
Chemical References |
- Ligands
- Phenanthrolines
- Ruthenium Compounds
- bathophenanthroline
- Ruthenium
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Topics |
- Breast Neoplasms
- Female
- Humans
- Ligands
- Phenanthrolines
- Ruthenium
(chemistry)
- Ruthenium Compounds
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