Spin-Orbit Charge-Transfer Intersystem Crossing (ISC) in Compact Electron Donor-Acceptor Dyads: ISC Mechanism and Application as Novel and Potent Photodynamic Therapy Reagents
Year: 2020
Authors: Wang ZJ., Ivanov M., Gao YT., Bussotti L., Foggi P., Zhang HM., Russo N., Dick B., Zhao JZ., Di Donato M., Mazzone G., Luo L., Fedin M.
Autors Affiliation: Dalian Univ Technol, Sch Chem Engn, State Key Lab Fine Chem, E-208 West Campus,2 Ling Gong Rd, Dalian 116024, Peoples R China; RAS, SB, Int Tomog Ctr, Inst Skaya Str 3A, Novosibirsk 630090, Russia; Novosibirsk State Univ, Pirogova Str 2, Novosibirsk 630090, Russia; Huazhong Univ Sci & Technol, Coll Life Sci & Technol, Natl Engn Res Ctr Nanomed, Wuhan 430074, Peoples R China; LENS, Via N Carrara 1, I-50019 Sesto Fiorentino, FI, Italy; Univ Perugia, Dipartimento Chim, Via Elce Sotto 8, I-06123 Perugia, Italy; Univ Calabria, Dipartimento Chim & Tecnol Chim, I-87036 Arcavacata Di Rende, Italy; Univ Regensburg, Inst Phys & Theoret Chem, Lehrstuhl Phys Chem, Univ Str 31, D-93053 Regensburg, Germany; Ist Nazl Ottica, Largo Enrico Fermi 6, I-50125 Florence, Italy.
Abstract: Spin-orbit charge-transfer intersystem crossing (SOCT-ISC) is useful for the preparation of heavy atom-free triplet photosensitisers (PSs). Herein, a series of perylene-Bodipy compact electron donor/acceptor dyads showing efficient SOCT-ISC is prepared. The photophysical properties of the dyads were studied with steady-state and time-resolved spectroscopies. Efficient triplet state formation (quantum yield phi(T)=60 %) was observed, with a triplet state lifetime (tau(T)=436 mu s) much longer than that accessed with the conventional heavy atom effect (tau(T)=62 mu s). The SOCT-ISC mechanism was unambiguously confirmed by direct excitation of the charge transfer (CT) absorption band by using nanosecond transient absorption spectroscopy and time-resolved electron paramagnetic resonance (TREPR) spectroscopy. The factors affecting the SOCT-ISC efficiency include the geometry, the potential energy surface of the torsion, the spin density for the atoms of the linker, solvent polarity, and the energy matching of the (CT)-C-1/(LE)-L-3 states. Remarkably, these heavy atom-free triplet PSs were demonstrated as a new type of efficient photodynamic therapy (PDT) reagents (phototoxicity, EC50=75 nm), with a negligible dark toxicity (EC50=78.1 mu m) compared with the conventional heavy atom PSs (dark toxicity, EC50=6.0 mu m, light toxicity, EC50=4.0 nm). This study provides in-depth understanding of the SOCT-ISC, unveils the design principles of triplet PSs based on SOCT-ISC, and underlines their application as a new generation of potent PDT reagents.
Journal/Review: CHEMISTRY-A EUROPEAN JOURNAL
Volume: 26 (5) Pages from: 1091 to: 1102
More Information: J.Z. thanks the NSFC (21673031, 21761142005, 21911530095 and 21421005), State Key Laboratory of Fine Chemicals (ZYTS201901) and the State Key Laboratory of Fine Chemicals (ZYTS201901) for financial support. M.F. thanks the Ministry of High Education and Science of Russia for access to EPR equipment. M.I. thanks RFBR (grant no. 19-29-10035). B.D. acknowledges Dalian University of Technology for the Haitian Professorship support. We thank Dr. Peter Sherin (ITC) for helpful discussions.KeyWords: Bodipy; electron spin polarization; perylenes; photodynamic therapy; spin-orbital charge-transfer intersystem crossing (SOCT-ISC)DOI: 10.1002/chem.201904306ImpactFactor: 5.236Citations: 83data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-24References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here
