Papish ET, Oladipupo OE. Factors that influence singlet oxygen formation vs. ligand substitution for light-activated ruthenium anticancer compounds.
Curr Opin Chem Biol 2022;
68:102143. [PMID:
35483128 DOI:
10.1016/j.cbpa.2022.102143]
[Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 11/03/2022]
Abstract
This review focuses on light-activated ruthenium anticancer compounds and the factors that influence which pathway is favored. Photodynamic therapy (PDT) is favored by π expansion and the presence of low-lying triplet excited states (e.g. 3MLCT, 3IL). Photoactivated chemotherapy (PACT) refers to light-driven ligand dissociation to give a toxic metal complex or a toxic ligand upon photo substitution. This process is driven by steric bulk near the metal center and weak metal-ligand bonds to create a low-energy 3MC state with antibonding character. With protic dihydroxybipyridine ligands, ligand charge can play a key role in these processes, with a more electron-rich deprotonated ligand favoring PDT and an electron-poor protonated ligand favoring PACT in several cases.
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