TY - JOUR

T1 - Primary processes in photophysics and photochemistry of a potential light-activated anti-cancer dirhodium complex

AU - Semionova, Veronica V

AU - Pozdnyakov, Ivan P

AU - Grivin, Vjacheslav P

AU - Eltsov, Ilia V

AU - Vasilchenko, Danila B

AU - Polyakova, Evgeniya V

AU - Melnikov, Alexei A

AU - Chekalin, Sergei V

AU - Wang, Lei

AU - Glebov, Evgeni M

N1 - The fnancial support of the Russian Science Foundation (Grant No. 22-23-00248) is gratefully acknowledged. Sergei V. Chekalin acknowledges funding by the research project FFUU2022-0004 of the Institute of Spectroscopy of the Russian Academy of Sciences. © 2023. The Author(s), under exclusive licence to European Photochemistry Association, European Society for Photobiology.

PY - 2024/1

Y1 - 2024/1

N2 - Photophysics and photochemistry of a potential light-activated cytotoxic dirhodium complex [Rh2(µ-O2CCH3)2(bpy)(dppz)](O2CCH3)2, where bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine (Complex 1 or Rh2) in aqueous solutions was studied by means of stationary photolysis and time-resolved methods in time range from hundreds of femtoseconds to microseconds. According to the literature, Complex 1 demonstrates both oxygen-dependent (due to singlet oxygen formation) and oxygen-independent cytotoxicity. Photoexchange of an acetate ligand to a water molecule was the only observed photochemical reaction, which rate was increased by oxygen removal from solutions. Photoexcitation of Complex 1 results in the formation of the lowest triplet electronic excited state, which lifetime is less than 10 ns. This time is too short for diffusion-controlled quenching of the triplet state by dissolved oxygen resulting in 1O2 formation. We proposed that singlet oxygen is produced by photoexcitation of weakly bound van der Waals complexes [Rh2…O2], which are formed in solutions. If this is true, no oxygen-independent light-induced cytotoxicity of Complex 1 exists. Residual cytotoxicity deaerated solutions are caused by the remaining [Rh2…O2] complexes.

AB - Photophysics and photochemistry of a potential light-activated cytotoxic dirhodium complex [Rh2(µ-O2CCH3)2(bpy)(dppz)](O2CCH3)2, where bpy = 2,2'-bipyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine (Complex 1 or Rh2) in aqueous solutions was studied by means of stationary photolysis and time-resolved methods in time range from hundreds of femtoseconds to microseconds. According to the literature, Complex 1 demonstrates both oxygen-dependent (due to singlet oxygen formation) and oxygen-independent cytotoxicity. Photoexchange of an acetate ligand to a water molecule was the only observed photochemical reaction, which rate was increased by oxygen removal from solutions. Photoexcitation of Complex 1 results in the formation of the lowest triplet electronic excited state, which lifetime is less than 10 ns. This time is too short for diffusion-controlled quenching of the triplet state by dissolved oxygen resulting in 1O2 formation. We proposed that singlet oxygen is produced by photoexcitation of weakly bound van der Waals complexes [Rh2…O2], which are formed in solutions. If this is true, no oxygen-independent light-induced cytotoxicity of Complex 1 exists. Residual cytotoxicity deaerated solutions are caused by the remaining [Rh2…O2] complexes.

KW - Dirhodium complexes

KW - Laser flash photolysis

KW - Photo-activated chemotherapy

KW - Photochemistry

KW - Photophysics

KW - Ultrafast TA spectroscopy

KW - Antineoplastic Agents/pharmacology

KW - Oxygen

KW - Singlet Oxygen

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85178954749&origin=inward&txGid=1a975781d9b22e2f3802fd01689c0511

UR - https://www.mendeley.com/catalogue/2c219975-d589-3d76-82ff-a26b558eb950/

U2 - 10.1007/s43630-023-00509-y

DO - 10.1007/s43630-023-00509-y

M3 - Article

C2 - 38066379

VL - 23

SP - 153

EP - 162

JO - Photochemical and Photobiological Sciences

JF - Photochemical and Photobiological Sciences

SN - 1474-905X

IS - 1

ER -