58345-97-4Relevant academic research and scientific papers
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.
Cobalt bis(2-ethylhexanoate) and terpyridine derivatives as catalysts for the hydrosilylation of olefins
Dai, Zinan,Yu, Zehao,Bai, Ying,Li, Jiayun,Peng, Jiajian
, (2020/10/14)
A simple method for the hydrosilylation of olefins by using air-stable cobalt catalysts is developed. The catalyst system is composed of simple, cheap, and readily available cobalt(II) salts and well-defined terpyridine derivatives as cocatalysts or ligands, and the hydrosilylation processes can be processed smoothly under mild conditions without either Grignard reagents or NaHBEt3 as activator.
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.
Coordination Environment Prevents Access to Intraligand Charge-Transfer States through Remote Substitution in Rhenium(I) Terpyridinedicarbonyl Complexes
Fernández-Terán, Ricardo J.,Sévery, Laurent
, p. 1325 - 1333 (2021/01/11)
Six rhenium(I) κ3N-dicarbonyl complexes with 4′-(4-substituted phenyl)terpyridine ligands were evaluated in their ground and excited states. These complexes, bearing substituents of different electron-donating strengths - from CN to NMe2 - were studied by a combination of transient IR (TRIR), electrochemistry, and IR spectroelectrochemistry, as well as time-dependent density functional theory (TD-DFT). They exhibit panchromatic absorption and can act as stronger photoreductants than their tricarbonyl counterparts. The ground- and excited-state potentials, absorption maxima, and lifetimes (250-750 ps) of these complexes correlate well with the Hammett σp substituent constants, showing the systematic effect of remote substitution in the ligand framework. TRIR spectroscopy allowed us to assign the lowest singlet and triplet excited states to a metal-to-ligand charge-transfer (MLCT) character. This result contrasts our previous report on analogous κ2N-tricarbonyl complexes, where remote substitution switched the character from MLCT to intraligand charge transfer. With the help of TD-DFT calculations, we dissect the geometric and electronic effects of coordination of the third pyridine, local symmetries, and increasing conjugation length. These results give valuable insights for the design of complexes with long-lived triplet excited states and enhanced absorption throughout the visible spectrum, while showcasing the boundaries of the excited-state switching strategy via remote substitution.
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.
Chemical and photochemical behavior of ruthenium nitrosyl complexes with terpyridine ligands in aqueous media
Labra-Vázquez, Pablo,Bocé, Mathilde,Tassé, Marine,Mallet-Ladeira, Sonia,Lacroix, Pascal G.,Farfán, Norberto,Malfant, Isabelle
, p. 3138 - 3154 (2020/03/19)
The synthesis and behavior in water of a set of various cis(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) and trans(Cl,Cl)-[R-tpyRuCl2(NO)](PF6) (R = fluorenyl, phenyl, thiophenyl; tpy = 2,2′:6′,2′′-terpyridine) complexes are presented. In any case, one chlorido ligand is substituted by a hydroxo ligand and the final species arises as a single trans(NO,OH) isomer, whatever the nature of the starting cis/trans(Cl,Cl) complexes. Six X-ray crystal structures are presented for cis(Cl,Cl)-[thiophenyl-tpyRuCl2(NO)](PF6) (cis-3a), trans(Cl,Cl)-[thiophenyl-tpyRuCl2(NO)](PF6) (trans-3a), trans(NO,OH)-[phenyl-tpyRu(Cl)(OH)(NO)](PF6) (4a), trans(NO,OH)-[thiophenyl-tpyRu(Cl)(OH)(NO)](PF6) (4b), trans(NO,OEt)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF6) (5a), and trans(NO,OH)-[phenyl-tpyRu(Cl)(OEt)(NO)](PF6) (5b) compounds. The different cis/trans(Cl,Cl) complexes exhibit an intense low-lying transition in the λ = 330-390 nm range, which appears to be slightly blue-shifted after Cl → OH substitution. In water, both cis/trans(Cl,Cl) isomers are converted to a single trans(NO,OH) isomer in which one chlorido- is replaced by one hydroxo-ligand, which avoids tedious separation workout. The water stable trans(NO,OH)-species all release NO with quantum yields of 0.010 to 0.075 under irradiation at 365 nm. The properties are discussed with computational analysis performed within the framework of Density Functional Theory.
A convenient method for synthesis of terpyridines: Via a cooperative vinylogous anomeric based oxidation
Karimi, Fatemeh,Yarie, Meysam,Zolfigol, Mohammad Ali
, p. 25828 - 25835 (2020/07/28)
The presented study is the first report of the synthesis of terpyridines in the presence of a nanomagnetic catalyst instead of harmful reagents. Herein, Fe3O4&at;O2PO2(CH2)2NH3+CF3CO2- as a retrievable nanocatalyst with magnetic properties was applied for the multi-component reaction between acetylpyridine derivatives (2 or 3 or 4-isomer), aryl aldehydes and ammonium acetate under conventional heating conditions in the absence of any solvent. The derived terpyridines were obtained with acceptable yields and brief reaction times via a cooperative vinylogous anomeric based oxidation route. Fe3O4&at;O2PO2(CH2)2NH3+CF3CO2- showed a high capability for recovery and reuse in the mentioned reaction.
Rhodium-terpyridine catalyzed redox-neutral depolymerization of lignin in water
Liu, Yuxuan,Li, Changzhi,Miao, Wang,Tang, Weijun,Xue, Dong,Xiao, Jianliang,Zhang, Tao,Wang, Chao
supporting information, p. 33 - 38 (2020/01/13)
Simple rhodium terpyridine complexes were found to be suitable catalysts for the redox neutral cleavage of lignin in water. Apart from cleaving lignin model compounds into ketones and phenols, the catalytic system could also be applied to depolymerize dioxasolv lignin and lignocellulose, affording aromatic ketones as the major monomer products. The (hemi)cellulose components in the lignocellulose sample remain almost intact during lignin depolymerization, providing an example of a "lignin-first" process under mild conditions. Mechanistic studies suggest that the reaction proceeds via a rhodium catalyzed hydrogen autotransfer process.
Synthesis, characterization and anticancer mechanism studies of fluorinated cyclometalated ruthenium(ii) complexes
Wen, Ya,Ouyang, Cheng,Li, Quanwen,Rees, Thomas W.,Qiu, Kangqiang,Ji, Liangnian,Chao, Hui
supporting information, p. 7044 - 7052 (2020/06/04)
The drug-resistance of cancer cells has become a major obstacle to the development of clinical drugs for chemotherapy. In order to overcome cisplatin-resistance, seven cyclometalated ruthenium(ii) complexes were synthesized with a varying degree of fluorine substitution, for use as anticancer agents. A cytotoxicity assay testified that the complexes possessed a more cytotoxic effect than cisplatin towards the cisplatin-resistant cell line A549R. The number of fluorine atoms regulated the lipophilicity of the complexes, but the relationship was not linear.Ru1containing one fluorine atom had the highest lipophilicity and the best therapeutic effect. The complexes enter cells through an energy-dependent pathway and then localize in the nuclei and mitochondria. The complexes induced nuclear dysfunction by the inhibition of DNA replication as well as mitochondrial dysfunction by the loss of membrane potential. The damage to these vital organelles leads to cell apoptosisviathe caspase 3/7 pathway. Our results indicated that the modulation of the number of fluorine atoms in therapeutic agents can have a profound effect andRu1is a complex with a high potential as a drug for the treatment of cisplatin-resistant cancer.
A Mitochondrion-Localized Two-Photon Photosensitizer Generating Carbon Radicals Against Hypoxic Tumors
Chao, Hui,Chen, Yu,Ji, Liangnian,Kuang, Shi,Liao, Xinxing,Rees, Thomas W.,Sun, Lingli,Zeng, Leli,Zhang, Xianrui,Zhang, Xiting
supporting information, p. 20697 - 20703 (2020/09/07)
The efficacy of photodynamic therapy is typically reliant on the local concentration and diffusion of oxygen. Due to the hypoxic microenvironment found in solid tumors, oxygen-independent photosensitizers are in great demand for cancer therapy. We herein report an iridium(III) anthraquinone complex as a mitochondrion-localized carbon-radical initiator. Its emission is turned on under hypoxic conditions after reduction by reductase. Furthermore, its two-photon excitation properties (λex=730 nm) are highly desirable for imaging. Upon irradiation, the reduced form of the complex generates carbon radicals, leading to a loss of mitochondrial membrane potential and cell death (IC50light=2.1 μm, IC50dark=58.2 μm, PI=27.7). The efficacy of the complex as a PDT agent was also demonstrated under hypoxic conditions in vivo. To the best of our knowledge, it is the first metal-complex-based theranostic agent which can generate carbon radicals for oxygen-independent two-photon photodynamic therapy.
