58345-97-4Relevant articles and documents
Photocytotoxic oxovanadium(IV) complexes of ferrocenyl-terpyridine and acetylacetonate derivatives
Balaji, Babu,Balakrishnan, Babita,Perumalla, Sravanakumar,Karande, Anjali A.,Chakravarty, Akhil R.
, p. 332 - 341 (2015)
Oxovanadium(IV) complexes [VO(Fc-tpy)(acac)](C104) (1), [VO(Fc-tpy)(nap-acac)](C104) (2), [VO(Fc-tpy)(py-acac)](C104) (3) and [VO(Ph-tpy)(py-acac)](C104) (4) of 4'-ferrocenyl-2,2':6',2"-terpyridine (Fc-tpy) and 4'-phenyl-2,2':6',2"-terpyridine (Ph-tpy) having monoanionic acetylacetonate (acac), naph-thylacetylacetonate (nap-acac) or pyre ny lace ty lace to nate (py-acac) ligand were prepared, characterized and their photocytotoxicity in visible light studied. The ferrocenyl complexes 1-3 showed an intense charge transfer band near 585 nm in DMFand displayed Fc'/Fc and V(1V)/V(111) redox couples near 0.66 V and -0.95 V vs. SCE in DMF-0.1 M TBAP. The complexes as avid binders to calf thymus DNA showed significant photocleavage of plasmid DNA in green light (568 nm) forming "OH radicals. The complexes that are photocytotoxic in HeLa and MCF-7 cancer cells in visible light (400 700 nm) with low dark toxicity remain nontoxic in normal fibroblast 3T3 cells. ICP-MS and fluorescence microscopic studies show significant cellular uptake of the complexes. Photo-irradiation of the complexes causes apoptotic cell death by ROS as evidenced from the DCFDA assay.
Living Long and Prosperous: Productive Intraligand Charge-Transfer States from a Rhenium(I) Terpyridine Photosensitizer with Enhanced Light Absorption
Fernández-Terán, Ricardo,Sévery, Laurent
supporting information, p. 1334 - 1343 (2020/10/09)
The ground- and excited-state properties of six rhenium(I) κ2N-tricarbonyl complexes with 4′-(4-substituted-phenyl)terpyridine ligands bearing substituents of different electron-donating abilities were evaluated. Significant modulation of the electrochemical potentials and a nearly 4-fold variation of the triplet metal-to-ligand charge-transfer (3MLCT) lifetimes were observed upon going from CN to OMe. With the more electron-donating NMe2group, we observed in the κ2N complex the appearance of a very strong absorption band, red-shifted by ca. 100 nm with respect to the other complexes. This was accompanied by a dramatic enhancement of the excited-state lifetime (380 vs 1.5 ns), and a character change from 3MLCT to intraligand charge transfer (3ILCT), despite the remote location of the substituent. The dynamics and character of the excited states of all complexes were assigned by combining transient IR spectroscopy, IR spectroelectrochemistry, and (time-dependent) density functional theory calculations. Selected complexes were evaluated as photosensitizers for hydrogen production, with the κ2N-NMe2complex resulting in a stable and efficient photocatalytic system reaching TONRevalues of over 2100, representing the first application of the 3ILCT state of a rhenium(I) carbonyl complex in a stable photocatalytic system.
Osmium Complex-Chromophore Conjugates with Both Singlet-to-Triplet Absorption and Long Triplet Lifetime through Tuning of the Heavy-Atom Effect
Kimizuka, Nobuo,Sasaki, Yoichi,Yanai, Nobuhiro
supporting information, (2022/02/09)
Os(II) complexes showing singlet-to-triplet absorption are of growing interest as a new class of triplet sensitizers that circumvent energy loss during intersystem crossing, and they enable effective utilization of input photon energy in various applications, such as photoredox catalysis, photodynamic therapy, and photon upconversion. However, triplet excited-state lifetimes of Os(II) complexes are often too short (τ a series of Os(II) and Ru(II) bis(terpyridine) complexes modified with perylene units. Phosphorescence lifetimes of these compounds strongly depend on the lifetimes of the perylenyl group-localized excited states that are shortened by the heavy-atom effect. The degree of heavy-atom effect can be largely circumvented by introducing meta-phenylene bridges, where the perylene unit retains its intrinsic long excited-state lifetime. The thermal activation to the short-lived excited states is suppressed, thanks to sufficient but still small energy losses during the IMET process. Involvement of the metal center was also confirmed by the prolonged lifetime by replacing Os(II) with Ru(II) that possesses a smaller spin-orbit coupling constant. These results indicate the importance of ligand structures that give a minimum heavy-atom effect as well as the sufficient energy gap among the excited states and fast IMET for elongating the triplet excited-state lifetime without sacrificing the excitation energy.
