Light‐responsive and Protic Ruthenium Compounds Bearing Bathophenanthroline and Dihydroxybipyridine Ligands Achieve Nanomolar Toxicity towards Breast Cancer Cells †

Autor: Charles Edwin Webster, Nicholas A. Ward, Fengrui Qu, Olaitan E. Oladipupo, Jessica L. Gray, Robert W. Lamb, Matthew K. Thompson, Alexa R. DeRegnaucourt, Spenser R. Brown, Yifei Xu, Sherri A. McFarland, Colin G. Cameron, James Fletcher Hall, Marco Bonizzoni, Ambar B. Shrestha, Yonghyun Kim, Elizabeth T. Papish, Courtney M. Petersen
Rok vydání: 2021
Předmět:
Zdroj: Photochem Photobiol
ISSN: 1751-1097
0031-8655
Popis: 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)]Cl(2) with n = 6 and 4 in 1(A) and 2(A), respectively). Full characterization data are reported for 1(A) and 2(A) and single crystal X-ray diffraction for 1(A). Both 1(A) and 2(A) are diprotic acids. We have studied 1(A), 1(B), 2(A), and 2(B) (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 1(A) and 2(A) produce singlet oxygen with quantum yields of 0.05 and 0.68, respectively, in acetonitrile. Complexes 1 and 2 are both photocytotoxic towards breast cancer cells, with complex 2 showing EC(50) 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 2(B) 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)O(2) generation explains the excellent photocytotoxicity of 2.
Databáze: OpenAIRE
Externí odkaz: