- Preparation and Bioactivity of Iridium(III) Phenanthroline Complexes with Halide Ions and Pyridine Leaving Groups
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A series of half-sandwich structural iridium(III) phenanthroline (Phen) complexes with halide ions (Cl?, Br?, I?) and pyridine leaving groups ([(η5-CpX)Ir(Phen)Z](PF6)n, Cpx: electron-rich cyclopentadienyl group, Z: leaving group) have been prepared. Target complexes, especially the Cpxbiph (biphenyl-substituted cyclopentadienyl)-based one, showed favourable anticancer activity against human lung cancer (A549) cells; the best one (Ir8) was almost five times that of cisplatin under the same conditions. Compared with complexes involving halide ion leaving groups, the pyridine-based one did not display hydrolysis but effectively caused lysosomal damage, leading to accumulation in the cytosol, inducing an increase in the level of intracellular reactive oxygen species and apoptosis; this indicated an anticancer mechanism of oxidation. Additionally, these complexes could bind to serum albumin through a static quenching mechanism. The data highlight the potential value of half-sandwich iridium(III) phenanthroline complexes as anticancer drugs.
- Liu, Xicheng,Shao, Mingxiao,Liang, Congcong,Guo, Jinghang,Wang, Guangxuan,Yuan, Xiang-Ai,Jing, Zhihong,Tian, Laijin,Liu, Zhe
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p. 557 - 564
(2020/11/30)
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- Metal iridium-ferrocene Schiff base complex and preparation method thereof
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The invention discloses a metal iridium-ferrocene Schiff base complex as well as a preparation method and anti-cancer application thereof. The structural formula is as shown in formula (I), R1 is hydrogen, methyl or phenyl, R2 is methyl or phenyl, and R3 is hydrogen or methyl. The growth inhibition rate of the target complex on human alveolar basal epithelial cancer cells (A549) and cervical cancer cells (Hela) is tested. Compared with a ferrocene thiosemicarbazide Schiff base ligand, a basic metal iridium dimer and a cis-platinum drug, the target complex shows potential anti-cancer activity, and the synergistic effect of the ferrocene and the metal iridium complex on the anti-cancer activity is proved. The target complex can be accumulated in lysosome tissues of A549 cells and cause lysosome damage, thereby causing cancer cell death.
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Paragraph 0077-0078
(2021/07/21)
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- Modulating the water oxidation catalytic activity of iridium complexes by functionalizing the Cp*-ancillary ligand: hints on the nature of the active species
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The catalytic activity toward NaIO4driven water oxidation of a series of [RCp*IrCl(μ-Cl)]2dimeric precursors, containing tetramethylcyclopentadienyl ligands with a variable R substituent (H,1; Me,2; Et,3;nPr,4; CH2CH2NH3+,5; Ph,6; 4-C6H4F,7; 4-C6H4OH,8; Bn,9), has been evaluated at 298 K and pH = 7 (with phosphate buffer). For each dimer, the effect of changing the catalyst (1-10 μM) and NaIO4(5-40 mM) concentration has been studied. All precursors exhibit a high activity with TOF values ranging from 101 min?1to 393 min?1and TON values being always those expected assuming a 100% yield. The catalytic activity was strongly affected by the nature of the R substituent. The highest TOF values were observed when R was electron-donating and small. The results of multiple consecutive injection experiments suggest that a fragment of the initial C5Me4R, still bearing the R-substituent, remains attached at iridium in the active species, despite the oxidativein situdegradation of the same ligand. The decrease of TOF in the second and third catalytic runs was completely ascribed to a drop of the redox potential caused by the conversion of IO4?into IO3?, according to the Nernst equation. This hypothesis was verified by performing catalytic experiments in which the initial redox potential (ΔE) was deliberately varied by using water solutions of IO4?/IO3?mixtures at different relative concentrations. Consistently, TOFversusΔEplots show that, for a given catalyst, the same TOF is obtained at a certain redox potential, irrespective of the initial reaction conditions used. All seems to indicate that after a short activation period, during which the transformation of the precursors occurs, individual active species for each dimer form and remain the same also after multiple additions of the sacrificial oxidant. It can be speculated that such active species are small iridium clusters bearing R-functionalized likelyO,O-bidentate ligands.
- Gatto, Giordano,De Palo, Alice,Carrasco, Ana C.,Pizarro, Ana M.,Zacchini, Stefano,Pampaloni, Guido,Marchetti, Fabio,Macchioni, Alceo
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p. 2885 - 2895
(2021/05/07)
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- A comparative analysis of the in vitro anticancer activity of iridium(III) {η5-C5Me4R} complexes with variable R groups
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Piano-stool iridium complexes based on the pentamethylcyclopentadienyl ligand (Cp*) have been intensively investigated as anticancer drug candidates and hold much promise in this setting. A systematic study aimed at outlining the effect of Cp* mono-derivatization on the antipro-liferative activity is presented here. Thus, the dinuclear complexes [Ir(η5-C5Me4R)Cl(μ-Cl)]2 (R = Me, 1a; R = H, 1b; R = Pr, 1c; R = 4-C6H4F, 1d; R = 4-C6H4OH, 1e), their 2-phenylpyridyl mononuclear derivatives [Ir(η5-C5Me4R)(kN,kCPhPy)Cl] (2a–d), and the dimethylsulfoxide complex [Ir{η5-C5Me4(4-C6H4OH)}Cl2(κS-Me2S=O)] (3) were synthesized, structurally characterized, and assessed for their cytotoxicity towards a panel of six human and rodent cancer cell lines (mouse melanoma, B16; rat glioma, C6; breast adenocarcinoma, MCF-7; colorectal carcinoma, SW620 and HCT116; ovarian carcinoma, A2780) and one primary, human fetal lung fibroblast cell line (MRC5). Complexes 2b (R = H) and 2d (4-C6H4F) emerged as the most active ones and were selected for further investigation. They did not affect the viability of primary mouse peritoneal cells, and their tumor-icidal action arises from the combined influence on cellular proliferation, apoptosis and senescence. The latter is triggered by mitochondrial failure and production of reactive oxygen and nitrogen species.
- De Palo, Alice,Draca, Dijana,Murrali, Maria Grazia,Zacchini, Stefano,Pampaloni, Guido,Mijatovic, Sanja,Maksimovic-Ivanic, Danijela,Marchetti, Fabio
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- In Vitro and in Vivo of Triphenylamine-Appended Fluorescent Half-Sandwich Iridium(III) Thiosemicarbazones Antitumor Complexes
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Half-sandwiched structure iridium(III) complexes appear to be an attractive organometallic antitumor agents in recent years. Here, four triphenylamine-modified fluorescent half-sandwich iridium(III) thiosemicarbazone (TSC) antitumor complexes were developed. Because of the enol configuration of the TSC ligands, these complexes formed a unique dimeric configuration. Aided by the appropriate fluorescence properties, studies found that complexes could enter tumor cells in an energy-dependent mode, accumulate in lysosomes, and result in the damage of lysosome integrity. Complexes could block the cell cycle, improve the levels of intrastitial reactive oxygen species, and lead to apoptosis, which followed an antitumor mechanism of oxidation. Compared with cisplatin, the antitumor potential in vivo and vitro confirmed that Ir4 could effectively inhibit tumor growth. Meanwhile, Ir4 could avoid detectable side effects in the experiments of safety evaluation. Above all, half-sandwich iridium(III) TSC complexes are expected to be an encouraging candidate for the treatment of malignant tumors.
- Shao, Mingxiao,Yao, Meimei,Liu, Xicheng,Gao, Chao,Liu, Weiyan,Guo, Jinghang,Zong, Jiawen,Sun, Xinzhuo,Liu, Zhe
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supporting information
p. 17063 - 17073
(2021/11/16)
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- Lysosome-targeted fluorescent metal iridium dimer, and preparation method and application thereof
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The invention discloses a lysosome-targeted fluorescent metal iridium dimer, and a preparation method and an application thereof. The structural formula of the compound is represented by formula (I),and R in the formula (I) is hydrogen, an alkyl group or an aryl group. Experiments for testing the inhibition rate of target compound (1 to 4) on the growth of human alveolar basal epithelial tumor cells (A549) and cervical tumor cells (Hela) show that the target compound has good antitumor activity in comparison with thiosemicarbazide-triphenylamine Schiff base ligands, basic metal iridium dimersand cis-platinum. In addition, when the substituent R is from hydrogen to the alkyl group to the aryl group, the activity of the target compound is improved. The introduction of triphenylamine and the special structure of the compound endow the compound with good fluorescence characteristics, and the compound can accumulate in lysosome in cells and cause lysosome damage, thereby causing tumor cell apoptosis.
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Paragraph 0025
(2020/06/17)
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- Ru, Rh and Ir metal complexes of pyridyl chalcone derivatives: Their potent antibacterial activity, comparable cytotoxicity potency and selectivity to cisplatin
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Half sandwich ruthenium, rhodium and iridium complexes containing pyridyl chalcone analogues (L1 and L2) are prepared by the reaction of [(arene)M(μ-Cl)Cl]2 (arene = benzene, p-cymene, Cp*) and (M = Ru, Rh/Ir)] with L1 and L2 in 1:2 (M:L) ratio. Eight neutral mononuclear complexes (1–8) were obtained and characterized using FT-IR, 1H NMR, 13C NMR, ESI mass and UV–Vis spectroscopic methods. The molecular structures of complexes 2, 4, 5 and 7 are established by single crystal X-ray diffraction studies. Antibacterial studies were tested against three strains of bacterial microorganisms Staphylococcus aureus (gram +ve), Klebsiella pneumoniae (gram ?ve) and Escherichia coli (gram ?ve). Further the cytotoxicity study of the pyridyl chalcone derivatives and their complexes were evaluated against the human colorectal cancer cell lines HT-29, HCT-116 p53+/+, HCT-116 p53?/? and ARPE-19 (non-cancer retinal epithelium).
- Banothu, Venkanna,Dkhar, Lincoln,Kaminsky, Werner,Kollipara, Mohan Rao,Phillips, Roger M.,Pinder, Emma
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- Iron-iridium heteronuclear metal complex, and preparation method and application thereof
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The invention discloses an iron-iridium heteronuclear metal complex, and a preparation method and an application thereof. The structural formula of the compound is represented by formula (I), and R inthe formula (I) is hydrogen, an alkyl group or an aryl group. Results of experiments for testing the inhibition rate of the target complex on the growth of human alveolar basal epithelial cancer cells (A549) and cervical cancer cells (Hela) show that compared with a ferrocene bipyridine derivative, a metal iridium dimer, a basic metal iridium bipyridine complex and cis-platinum, the target complex especially the complex with a cis-configuration has good anticancer activity, and the synergistic anticancer effect of ferrocene and the metal iridium complex is proved. When the substituent R is from a methyl group to a phenyl group, the activity of the complex is improved, which proves the synergistic effect of improving the electron donating capacity of the ligand on improving the anticanceractivity of the target complex. The target complexes may accumulate within the lysosome of the cell and result in lysosome damage, resulting in cancer cell apoptosis.
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Paragraph 0037
(2020/06/20)
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- Reinvestigating catalytic alcohol dehydrogenation with an iridium dihydroxybipyridine catalyst
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The examined catalyst [Cp*Ir(H2O)(6,6′-dhbp)]2+ (1; 6,6′-dhbp = 6,6′-dihydroxy-2,2′-bipyridine) was reported in 2012 as a highly efficient (92% conversion) and selective catalyst for the conversion of benzyl alcohol to benzaldehyde as the sole product via acceptorless dehydrogenation. We report herein that the observed conversion and selectivity data are not accurate but may have resulted, in part, from other products being produced that are not easily detected. Specifically, benzoic acid is formed as a byproduct via the disproportionation of benzaldehyde, but at high temperatures, most of the benzoic acid produced is converted in situ to benzene and carbon dioxide. While we can explain the observed selectivity, we cannot explain the observed conversion to products. In our hands, we observed 15% conversion to products under the original conditions. Other alcohol substrates were also examined and gave lower conversion to products and decreased selectivity in comparison with the original report. Acceptorless alcohol dehydrogenation to generate aldehydes is a potentially transformative technology which can allow chemists to replace stoichiometric oxidants that produce waste with efficient catalysts that only generate H2 gas as a byproduct. Thus, clarification of the 2012 report to indicate what conditions can lead to high efficiency and selectivity is a worthy topic of discussion in the literature.
- Brewster, Timothy P.,DeRegnaucourt, Alexa R.,Loadholt, Kylie H.,Papish, Elizabeth T.,Qu, Fengrui,Shrewsbury, Emily D.,Silprakob, Weerachai,Yao, Wenzhi
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supporting information
p. 3656 - 3662
(2020/11/23)
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- Synthesis, characterization, molecular structure and computational study of tetrahedral pentamethylcyclopentadienyl iridacycle complexes with α,β-conjugated Schiff base ligands
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Due to the excellent catalytic activities and phosphorescent properties that iridium complexes display, iridium chemistry has been of great interest for scientific investigation over the past 30 years. Iridium metallacycle analogues (also known as an iridacycles) bearing phenylpyridine (ppy) ligands have been well reported on, whilst complexes with R-phenyl-(3-R-phenylallylidene)amine, which is an α,β-conjugated Schiff base ligand, have not had the same attention, despite the fact that both ligands share a similar coordination mode. In this research, four pentamethylcyclopentadienyl iridacycle complexes, Ir1a-Ir1d, with different α,β-conjugated Schiff base ligands were synthesized from a di-μ-chloro-dichloro-bis-(η5-pentamethylcyclopentadienyl)diiridium(III) precursor. The iridacycle complexes were characterized using spectroscopic techniques and the molecular structures of Ir1ab-Ir1d were determined using X-ray crystallography. The X-ray results revealed that the iridacycle complexes have a tetrahedral geometry, the iridium centre being coordinated through the N[dbnd]C[sbnd]Cα[dbnd]Cβ moiety of the α,β-conjugated Schiff base ligand. Computational calculations with the B3LYP method and with LanL2DZ basis sets indicated that the HOMO-LUMO energy gaps Ir1b-Ir1d were in the range 3.31–3.36 eV. The OMe substituent at the C terminal has a greater impact on the HOMO energy level than the one at the N terminal.
- Daud, Adibah Izzati,Khairul, Wan M.,Liu, Zhi-Qiang,Ong, Kok Tong,Tay, Meng Guan
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- Fluorescent iridium(iii) coumarin-salicylaldehyde Schiff base compounds as lysosome-targeted antitumor agents
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Six fluorescent half-sandwich iridium(iii) coumarin-salicylaldehyde Schiff base (O^N) compounds ([(?5-Cp*)Ir(O^N)Cl]) were prepared and characterized. The introduction of a coumarin unit increased the antitumor activity (IC50: 9.9 ± 0.1 μM-40.7 ± 12.9 μM) of these compounds, the best of which was nearly two times that of clinical cisplatin. The results of laser confocal microscopy demonstrated that these compounds possessed an energy-dependent cellular uptake mechanism, accumulated in the lysosomes (Pearson co-localization coefficient: ~0.7), damaged the integrity of the lysosomes, and induced apoptosis. The compounds could also decrease the mitochondrial membrane potential, catalyze the oxidation of the coenzyme (nicotinamide-adenine dinucleotide) and improve the levels of the intracellular reactive oxygen species, following an antitumor mechanism of oxidation. Additionally, these compounds could block the metastasis of tumor cells. Above all, these iridium(iii) compounds show potential as antitumor agents with dual functions: lysosomal damage and anti-metastasis.
- Ge, Xingxing,Liu, Cong,Liu, Xicheng,Liu, Zhe,Shang, Wenjing,Tian, Laijin,Wang, Qinghui,You, Jinmao,Yuan, Xiang Ai,Zhang, Lei,Zhang, Yue
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supporting information
p. 5988 - 5998
(2020/05/25)
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- Preparation and the anticancer mechanism of configuration-controlled Fe(ii)-Ir(iii) heteronuclear metal complexes
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A series of configuration-controlled Fe(ii)-Ir(iii) heteronuclear metal complexes, including ferrocene and half-sandwich like iridium(iii) complex units, have been designed and prepared. These complexes show better anticancer activity than cisplatin under the same conditions, especiallycis-configurational ones. Laser confocal microscopy analysis confirms that the complexes follow a non-energy-dependent cellular uptake mechanism, accumulate in lysosomes (pearson co-localization coefficient: ~0.7), lead to lysosomal damage, and eventually induce apoptosis. These complexes can reduce the mitochondrial membrane potential, disturb the cell circle, catalyze the oxidation of nicotinamide-adenine dinucleotide (NADH) and increase the levels of intracellular reactive oxygen species (ROS), following an anticancer mechanism of oxidation. In addition, the complexes could bind to serum protein, and transport through it. Above all, the Fe(ii)-Ir(iii) heteronuclear metal complexes hold promise as potential anticancer agents for further study.
- Shao, Mingxiao,Liu, Xicheng,Sun, Yiwei,Dou, Shuaihua,Chen, Qi,Yuan, Xiang-Ai,Tian, Laijin,Liu, Zhe
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supporting information
p. 12599 - 12609
(2020/10/05)
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- Lysosomal-targeted anticancer half-sandwich iridium(III) complexes modified with lonidamine amide derivatives
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Ten half-sandwich iridium complexes containing lonidamine amide derivatives were synthesized and characterized. Unlike lonidamine, which acts on mitochondria, its iridium complexes successfully targeted lysosomes and induced lysosomal damage. Antiproliferation studies showed that most of the complexes have higher anticancer activity against A549 and HeLa cells than cisplatin. The antitumor activity of complex 6 is 2.69 times that of cisplatin against A549 cells. We also performed antitumor tests on ligands L1 and L5, and proved that they exhibit excellent antitumor activity only after binding to the metal center. The bovine serum albumin (BSA) binding test showed that the complexes had the ability to bind to BSA, and they interact with BSA by a static mechanism. The complexes can also cause changes in mitochondrial membrane potential and can produce active oxygen species better than active control. NADH/NAD+ transformation experiments were used to determine if the production of ROS was caused by the transformation of NADH/NAD+. We also explored the way that the complexes enter cells.
- Xie, Yongkang,Zhang, Shumiao,Ge, Xingxing,Ma, Wenli,He, Xiaolin,Zhao, Yao,Ye, Juan,Zhang, Hongmin,Wang, Anwei,Liu, Zhe
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- Versatile coordination modes of benzothiazole hydrazone derivatives towards Ru(II), Rh(III) and Ir(III) complexes and their reactivity studies with azides and activated alkynes
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Metal precursors of the type [(p-cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) on reacting with benzothiazole hydrazones ligands (L1 = benzylidenehydrazinyl benzothiazole, L2 = 4-flourobenzylidenehydrazinyl benzothiazole and L3 = 4-methylbenzylidenehydrazinyl benzothiazole) in the ratio of 1:2 (M:L), leads to the formation of range of complexes. In the case of ruthenium precursor with ligand L1, a cationic complex [(p-cymene)Ru{κ2(NN’)L1}Cl]Cl (1) is formed whereas with L2 and L3 neutral complexes [(p-cymene)Ru{κ2(NN’)L2/L3}Cl2] (4 and 7) are obtained. Rhodium precursor with L1 and L2 forms mono dentate neutral complexes [Cp*Rh{κ1(N)L1/L2}Cl2] (2 and 5) while with L3 bidentate NN′ bonding complex [Cp*Rh{κ1(NN’)L3}Cl] (8) is obtained. However, iridium precursor with these ligands yielded neutral bidentate complexes (3, 6 and 9) having the general formula [Cp*Ir{κ2(NN’)L}Cl] where L = L1, L2 and L3 respectively. Some of these complexes have been treated with sodium azide to yield azido compounds. Conformational switching of the benzothiazole hydrazone derivatives of complexes 2 and 5 from trans (E) to cis (Z) are observed on treatment with sodium azide. These azido complexes obtained, have been treated with activated acetylenes of dimethyl and diethyl acetylene carboxylates, which undergo [3 + 2] cycloadditions to form arene ruthenium triazolato complexes. All these complexes have been characterized by analytical, spectroscopic and single crystal x-ray diffraction studies. These complexes have also been carried out for antibacterial studies, but unfortunately none of these compounds or ligands exhibits antibacterial activity towards gram-positive and gram-negative bacteria.
- Dkhar, Lincoln,Kaminsky, Werner,Poluri, Krishna Mohan,Kollipara, Mohan Rao
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- Half sandwich platinum group metal complexes of thiourea derivative ligands with benzothiazole moiety possessing anti-bacterial activity and colorimetric sensing: Synthesis and characterisation
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Complexes 1–9 were prepared by the reaction of [(arene)MCl2]2 (arene = p-cymene, Cp*; M = Ru, Rh and Ir) with thiourea derivative ligands L1, L2 and L3. These complexes have been isolated as cationic bidentate (N, S), neutral bidentate (N, S) as well as neutral mono-dentate (S) complexes. Anti-bacterial activity studies were carried out for these complexes as well as the ligands against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli; Klebsiella pneumoniae) in which all the complexes (except complexes 2 and 6) as well as the ligands (except L3) showed anti-bacterial activity. In addition to the biological studies, colorimetric sensing study using silver nanoparticles was also carried out where, ligands L1 and L3 showed agglomeration effects.
- Shadap, Lathewdeipor,Diamai, Siewdorlang,Banothu, Venkanna,Negi,Adepally, Uma,Kaminsky, Werner,Kollipara, Mohan Rao
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- Synthesis, characterization and chemosensitivity studies of half-sandwich ruthenium, rhodium and iridium complexes containing к1(S) and к2(N,S) aroylthiourea ligands
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The reaction of [(p-cymene)RuCl2]2 and [Cp*MCl2]2 (M = Rh/Ir) metal precursors with aroylthiourea ligands (L1-L3) yielded a series of neutral mono-dentate complexes 1–9. The neutral mono-dentate coordination of aroylthiourea with metals via S atom was confirmed by single crystal X-ray diffraction study. Further reaction of mono-dentate complexes 1–9 with excess NaN3 in polar solvent resulted in the formation of highly strained four member ring к2(N,S) azido complexes 10–18. Further these complexes were treated with activated alkynes to isolate triazole complexes, but unfortunately the reaction was unsuccessful. All these complexes were fully characterized by various spectroscopic techniques. The molecular structures of the representative complexes have been determined by single crystal X-ray diffraction studies. The molecular structures of the complexes revealed typical piano stool geometry around the metal center. The chemosensitivity activities of the complexes 1–9 evaluated against the cancer cell line HCT-116 (human colorectal carcinoma) and ARPE-19 (human retinal epithelial cells) cell line. Of these, complex 3 was the most potent and whilst its potency was less than cisplatin, its selectivity for cancer as opposed to non-cancer cell lines in vitro was comparable to cisplatin.
- Lapasam, Agreeda,Hussain, Omar,Phillips, Roger M.,Kaminsky, Werner,Kollipara, Mohan Rao
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p. 272 - 280
(2018/11/26)
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- Spectroscopic and electrochemical study for evaluating DNA interaction activity of 4-(3-halophenyl)-6-(pyridin-2-yl)pyrimidin-2-amine based piano stool Cp* Rh (III) and Ir (III) complexes
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Six novel organometallic half sandwich complexes [(η5-C5Me5)M(L1–3)Cl]Cl.2H2O were synthesized using [{(η5-C5Me5)M(μ-Cl)Cl2], where M?=?Ir (III)/Rh (III) and L1–3?=?three pyridyl pyrimidine based ligands; and characterized by NMR, Infra-red spectroscopy, conductance, elemental and thermal analysis. The complex-DNA binding mode and/or strength evaluated using absorption titration, electrochemical studies and hydrodynamic measurement proposed intercalative binding mode, which was also confirmed by molecular docking study. Differential pulse voltammetry and cyclic voltammetry studies indicated an alteration in oxidation and reduction potentials of complexes (M+4/M+3) in presence of CT-DNA. The metal complexes can cleave plasmid DNA as proposed in gel electrophoretic analysis. The LC50 values of complexes evaluated on brine shrimp suggested their potent cytotoxic nature.
- Vekariya, Pankajkumar A.,Karia, Parag S.,Bhatt, Bhupesh S.,Patel, Mohan N.
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- Challenges in cyclometalation: Steric effects leading to competing pathways and η1,η2-cyclometalated iridium(iii) complexes
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The iridation of (R)-N,N-dimethyl-1-(1-naphthyl)ethylamine in the presence of a base afforded an assortment of products ranging from organic molecules to coordinated systems and cyclometalated complexes. The transformation affirmed the postulation where steric effects within the coordination sphere favor a β-hydride elimination-like decomposition pathway, competing alongside ortho-metalation, thus leading to iminium intermediates. The same procedure also generated an unprecedented carbocyclic η1,η2-cycloiridated species that could not be attained from the direct cyclometalation of its organic ligand.
- Chen, Houguang Jeremy,Teo, Ronald Hong Xiang,Wong, Jonathan,Li, Yongxin,Pullarkat, Sumod A.,Leung, Pak-Hing
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p. 13046 - 13051
(2018/10/02)
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- With anticancer activity of ion iridium complex and its preparation method, application (by machine translation)
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The invention relates to a metal complex, in particular relates to a ion iridium complexes with anticancer activity and its preparation method, application, which belongs to the chemical-pharmaceutical field. The complex structural formula is: , The present invention provides organic iridium complex is a phosphorus-oxygen atom with the iridium coordination complex, has high anticancer activity, small side effect, property is good, and is not easy to produce the drug resistance; the invention provides a preparation method, the synthesis efficiency is high, in the preparation of the complexes in biomedical Sciences has broad application prospects; the invention [P, O] introduced into the neutral ligands of this complex has androgenic activity, for the follow-up anti-cancer pharmaceutical ligand synthetic study provides a new line of research. (by machine translation)
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Paragraph 0034; 0035
(2018/03/01)
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- Iridium- and Rhodium-Catalyzed Directed C-H Heteroarylation of Benzaldehydes with Benziodoxolone Hypervalent Iodine Reagents
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The C-H heteroarylation of benzaldehydes with indoles and pyrroles was realized using the benziodoxolone hypervalent iodine reagents indole- and pyrroleBX. Functionalization of the aldehyde C-H bond using either an o-hydroxy or amino directing group and catalyzed by an iridium or a rhodium complex allowed the synthesis of salicyloylindoles and (2-sulfonamino)benzoylindoles, respectively, with good to excellent yields (74-98%). This new transformation could be carried out under mild conditions (rt to 40 °C) and tolerated a broad range of functionalities, such as ethers, halogens, carbonyls, or nitro groups.
- Grenet, Erwann,Waser, Jér?me
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supporting information
p. 1473 - 1476
(2018/03/09)
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- Novel and Versatile Imine-N-Heterocyclic Carbene Half-Sandwich Iridium(III) Complexes as Lysosome-Targeted Anticancer Agents
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We, herein, report the synthesis, characterization, luminescence properties, anticancer, and antibacterial activities of a family of novel half-sandwich iridium(III) complexes of the general formula [(n5-Cpx)Ir(C^N)Cl]PF6- [Cpx = pentamethylcyclopentadienyl (Cp) or tetramethyl(biphenyl)-cyclopentadienyl (Cpxbiph)] bearing versatile imine-N-heterocyclic carbene ligands. In this complex framework, substituents on four positions could be modulated, which distinguishes this class of complex and provides a large amount of flexibility and opportunity to tune the cytotoxicity of complexes. The X-ray crystal structures of complexes 4 and 10 exhibit the expected "piano-stool" geometry. With the exception of 1, 2, and 11, each complex shows potent cytotoxicity, with IC50 (half-maximum inhibitory concentration) values ranging from 1.99 to 25.86 μM toward A549 human lung cancer cells. First, the effect of four positions bearing different substituents in the complex framework on the anticancer activity, that is, structure-activity relationship, was systematically studied. Complex 8 (IC50 = 1.99 μM) displays the highest anticancer activities, whose cytotoxicity is more than 10-fold higher than that of the clinical platinum drug cisplatin against A549 cancer cells. Second, their chemical reactivity including nucleobases binding, catalytic activity in converting coenzyme NADH to NAD+, reaction with glutathione (GSH), and bovine serum albumin (BSA) binding is investigated. No reaction with nucleobase is observed. However, these iridium(III) complexes bind rapidly to GSH and can catalyze oxidation of NADH to NAD+. In addition, they show moderate binding affinity to BSA and the fluorescence quenching of BSA by the iridium (III) complexes is due to the static quenching. Third, the mode of cell death was also explored through flow cytometry experiments, including cell cycle, apoptosis induction, reactive oxygen species (ROS) and mitochondrial membrane potential. It seems that cell cycle perturbation, apoptosis induction, increase of ROS level and loss of mitochondrial membrane potential together contribute to the anticancer potency of these complexes. Last, the use of confocal microscopy provides insights into the microscopic mechanism that the typical and most active complex 8 enters A549 lung cancer cells mainly through energy-dependent pathway and is located in lysosome. Furthermore, lysosome damage and nuclear morphology were detected by confocal microscopy. Nuclear condensation and apoptotic bodies may finally induce cells apoptosis. Interestingly, complex 8 also shows antibacterial activity against Gram-positive Staphylococcus aureus. This work may provide an alternative and effective strategy to smart design of potent organometallic half-sandwich iridium(III) anticancer drugs.
- Yang, Yuliang,Guo, Lihua,Tian, Zhenzhen,Gong, Yuteng,Zheng, Hongmei,Zhang, Shumiao,Xu, Zhishan,Ge, Xingxing,Liu, Zhe
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supporting information
p. 11087 - 11098
(2018/09/14)
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- Carbene imine semi-sandwich iridium complex capable of targeting lysosome as well as preparation method and application thereof
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The invention relates to a metal compound, in particular to a carbene imine semi-sandwich iridium complex capable of targeting lysosome as well as a preparation method and application thereof, and belongs to the technical field of chemical pharmacy. The compound has a structure formula shown in the description. The prepared compound can be easily modified, can be modified in a plurality of positions, has good anticancer activity, and belongs to a novel kind of potential anticancer medicine. The condition that the semi-sandwich iridium complex can perform cell imaging through laser a co-focusing microscope is found for the first time; the problem of unclear targeting of the semi-sandwich compound is solved; a method for effectively studying the anticancer mechanism of the compound is provided; the cell imaging result shows that the compound can well target the lysosome.
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Paragraph 0056; 0057
(2018/09/08)
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- Rhodamine B modified semi-sandwich iridium complex with fluorescence characteristics as well as preparation method and application thereof
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The invention particularly relates to a rhodamine B modified semi-sandwich iridium complex with fluorescence characteristics as well as a preparation method and application thereof, and belongs to thefield of chemical pharmacy. The complex has a molecular structural formula shown in the description. The rhodamine B is creatively used for modifying the iridium complex; the high anti-cancer activity and the mitochondria targeting performance can be given to the whole complex; the selectivity can be realized on cancer cells; the ideal goals of action process visibility and real-time detection performance can be achieved; the important significance is realized on the medicine targeting performance study. The N^N is used as the two-tooth chelation anion ligand; a novel ion type iridium complexwith higher anti-cancer activity and fluorescence characteristics is synthesized; the complex has the good effect and high activity in anti-cancer and cell imaging aspects.
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Paragraph 0030
(2018/07/28)
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- Semi-sandwich iridium complex having fluorescent property and containing N-N two-tooth chelated ligand, and preparation method and application of semi-sandwich iridium complex
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The invention relates to a semi-sandwich iridium complex having fluorescent properties and containing N-N two-tooth chelated ligand and belongs to the field of chemical pharmaceutical. The molecular structural formula of the iridium complex is as shown in the specification. As the iridium complex is creatively modified with rhodamine B, the whole complex has high anti-cancer activity and mitochondria targeting, has selectivity upon cancer cells, action process visibility and ideal purposes of real-time detection, and has a great significance on medicine targeting research. N-N is adopted as anion ligand for two-tooth chelation, the novel anionic iridium complex with relatively high anti-cancer activity and fluorescent properties can be synthesized, and the complex is good in effect and high in activity in cancer prevention and cell imaging.
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Paragraph 0032
(2018/07/30)
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- Half-Sandwich Iridium and Ruthenium Complexes: Effective Tracking in Cells and Anticancer Studies
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Half-sandwich metal-based anticancer complexes suffer from uncertain targets and mechanisms of action. Herein we report the observation of the images of half-sandwich iridium and ruthenium complexes in cells detected by confocal microscopy. The confocal microscopy images showed that the cyclopentadienyl iridium complex 1 mainly accumulated in nuclei in A549 lung cancer cells, whereas the arene ruthenium complex 3 is located in mitochondria and lysosomes, mostly in mitochondria, although both complexes entered A549 cells mainly through energy-dependent active transport. The nuclear morphological changes caused by Ir complex 1 were also detected by confocal microscopy. Ir complex 1 is more potent than cisplatin toward A549 and HeLa cells. DNA binding studies involved interaction with the nucleobases 9-ethylguanine, 9-methyladenine, ctDNA, and plasmid DNA. The determination of bovine serum albumin binding was also performed. Hydrolysis, stability, nucleobase binding, and catalytic NAD+/NADH hydride transfer tests for complexes 1 and 3 were also carried out. Both complexes activated depolarization of mitochondrial membrane potential and intracellular ROS overproduction and induced cell apoptosis. Complex 3 arrested the cell cycle at the G0/G1 phase by inactivation of CDK 4/cyclin D1. This work paves the way to track and monitor half-sandwich metal complexes in cells, shines a light on understanding their mechanism of action, and indicates their potential application as theranostic agents.
- Li, Juanjuan,Guo, Lihua,Tian, Zhenzhen,Zhang, Shumiao,Xu, Zhishan,Han, Yali,Li, Ruixia,Li, Yan,Liu, Zhe
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p. 13552 - 13563
(2018/10/20)
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- Iridium-catalysed primary alcohol oxidation and hydrogen shuttling for the depolymerisation of lignin
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Lignin is a potentially abundant renewable resource for the production of aromatic chemicals, however its selective depolymerisation is challenging. Here, we report a new catalytic system for the depolymerisation of lignin to novel, non-phenolic monoaromatic products based on the selective β-O-4 primary alcohol dehydrogenation with a Cp?Ir-bipyridonate catalyst complex under basic conditions. We show that this system is capable of promoting the depolymerisation of model compounds and isolated lignins via a sequence of selective primary alcohol dehydrogenation, retro-aldol (Cα-Cβ) bond cleavage and in situ stabilisation of the aldehyde products by transfer (de)hydrogenation to alcohols and carboxylic acids. This method was found to give good to excellent yields of cleavage products with both etherified and free-phenolic lignin model compounds and could be applied to real lignin to generate a range of novel non-phenolic monomers including diols and di-acids. We additionally show, by using the same catalyst in a convergent, one-pot procedure, that these products can be selectively channelled towards a single di-acid product, giving much simpler product mixtures as a result.
- Lancefield, Christopher S.,Teunissen, Lucas W.,Weckhuysen, Bert M.,Bruijnincx, Pieter C. A.
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supporting information
p. 3214 - 3221
(2018/07/31)
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- CO2 as a hydrogen vector-transition metal diamine catalysts for selective HCOOH dehydrogenation
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The homogeneous catalytic dehydrogenation of formic acid in aqueous solution provides an efficient in situ method for hydrogen production, under mild conditions, and at an adjustable rate. We synthesized a series of catalysts with the chemical formula [(Cp?)M(N-N′)Cl] (M = Ir, Rh; Cp? = pentamethylcyclopentadienyl; N-N = bidentate chelating nitrogen donor ligands), which have been proven to be active in selective formic acid decomposition in aqueous media. The scope of the study was to examine the relationship between stability and activity of catalysts for formic acid dehydrogenation versus electronic and steric properties of selected ligands, following a bottom-up approach by increasing the complexity of the N,N′-ligands progressively. The highest turnover frequency, TOF = 3300 h-1 was observed with a Cp?Ir(iii) complex bearing 1,2-diaminocyclohexane as the N,N′-donor ligand. From the variable temperature studies, the activation energy of formic acid dehydrogenation has been determined, Ea = 77.94 ± 3.2 kJ mol-1. It was observed that the different steric and electronic properties of the bidentate nitrogen donor ligands alter the catalytic activity and stability of the Ir and Rh compounds profoundly.
- Fink, Cornel,Laurenczy, Gábor
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p. 1670 - 1676
(2017/02/10)
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- Selective Arene Cleavage by Direct Insertion of Iridium into the Aromatic Ring
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We report an unprecedented selective cleavage of aromatic C?C bonds through the insertion of well-defined iridium complexes into the aromatic ring of simple alkylarenes. The insertion occurs at 50–100 °C without the activation of weaker C?H and C?C bonds
- Jakoobi, Martin,Halcovitch, Nathan,Whitehead, George F. S.,Sergeev, Alexey G.
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supporting information
p. 3266 - 3269
(2017/03/17)
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- Half-sandwich iridium N-heterocyclic carbene anticancer complexes
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Half-sandwich pseudo-octahedral pentamethylcyclopentadienyl IrIII complexes of the type [(η5-Cpx)Ir(C^C)Cl]PF6, where Cpx is pentamethylcyclopentadienyl (Cp?), or its phenyl (Cpxph = C
- Wang, Chuanlan,Liu, Jinfeng,Tian, Zhenzhen,Tian, Meng,Tian, Laijin,Zhao, Wenqian,Liu, Zhe
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p. 6870 - 6883
(2017/07/10)
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- Novel half-sandwich iridium(iii) imino-pyridyl complexes showing remarkable: In vitro anticancer activity
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Seven novel half-sandwich IrIII cyclopentadienyl complexes, [(η5-Cpx)Ir(N^N)Cl]PF6, have been prepared and characterized, where Cpx is Cp? or the biphenyl derivative Cpxbiph (C5Me4C6H4C6H5), and the N^N-chelating ligands are imino-pyridyl Schiff-bases. The X-ray crystal structures of complexes 2A, 2B, and 3A have been determined. Excitingly, most of the complexes show potent antiproliferative activity towards A549 and HeLa cancer cells, except for Cp? complex 1A towards HeLa cells. Cpxbiph complex 2B displayed the highest potency, about 19 and 6 times more active than the clinically used drug cisplatin toward A549 and HeLa cells, respectively. These complexes undergo hydrolysis, and the kinetics data have been calculated. DNA binding has been studied by interaction with nucleobases 9-ethylguanine and 9-methyladenine, cleavage of plasmid DNA, and interaction with ctDNA. Interaction with DNA does not appear to be the major mechanism of action. Protein binding (bovine serum albumin, BSA) has been established by UV-Vis, fluorescence and synchronous spectroscopic studies. The stability of complex 2B in the presence of GSH was evaluated. The complexes catalytically convert coenzyme NADH to NAD+via hydride transfer. Cpxbiph complexes 2B and 4B induce cell apoptosis and arrest cell cycles at the S and G2/M phases towards A549 cancer cells and increase the reactive oxygen species dramatically, which appear to contribute to the remarkable anticancer activity.
- Li, Juanjuan,Guo, Lihua,Tian, Zhenzhen,Tian, Meng,Zhang, Shumiao,Xu, Ke,Qian, Yuchuan,Liu, Zhe
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p. 15520 - 15534
(2017/11/22)
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- Effect of Cp*Iridium(III) Complex and acid co-catalyst on conversion of furfural compounds to cyclopentanones or straight chain ketones
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In this paper, Cp*Ir (III) Complex and acid co-catalyst system was developed. By using Cp*Ir and γ-Al2O3 (Lewis acid), 5-hydroxymethylfurfural (5-HMF) can be converted efficiently to 3-hydroxymethyl cyclopentanone (HCPN). Meanwhile, Cp*Ir and Br?nsted acid can promote conversion of 5-HMF to 1-Hydroxy-2,5-hexanedione (HHD). The effect of Lewis acid and Br?nsted acid on the hydrogenation of furan derivatives was studied. Mechanism of conversion of 5-HMF to HCPN was discussed in detail and mechanism proposed by our predecessors was revised. Instead of being an intermediate for the formation of HCPN, it is believed that, HHD is a product of another reaction pathway. HHD condensed via Aldol reaction to produce 3-methylcyclopenten-2-ol-1-one (MCP) instead of HCPN. Under the promotion of Lewis acid, 5-HMF firstly convert to the precursor of HHD. After that, the reaction is through 4 π-electrocyclic ring closure process and HCPN was formed ultimately. Furthermore, we found that our Cp*Ir and acid co-catalyst system is suitable for a variety of furfural compounds. By using Cp*Ir, Br?nsted acid can promote conversion of furfural compounds to straight chain ketones and Lewis acid can promote the rearrangement of furfural compounds to cyclopentanone derivatives.
- Xu, Yong-Jian,Shi, Jing,Wu, Wei-Peng,Zhu, Rui,Li, Xing-Long,Deng, Jin,Fu, Yao
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p. 266 - 273
(2017/07/13)
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- Ligand Tuning in Pyridine-Alkoxide Ligated Cp?IrIII Oxidation Catalysts
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Six novel derivatives of pyridine-alkoxide ligated Cp?IrIII complexes, potent precursors for homogeneous water and C-H oxidation catalysts, have been synthesized, characterized, and analyzed spectroscopically and kinetically for ligand effects. Variation of alkoxide and pyridine substituents was found to affect their solution speciation, activation behavior, and oxidation kinetics. Application of these precursors to catalytic C-H oxidation of ethyl benzenesulfonate with aqueous sodium periodate showed that the ligand substitution pattern, solution pH, and solvent all have pronounced influences on initial rates and final conversion values. Correlation with O2 evolution profiles during C-H oxidation catalysis showed these competing reactions to occur sequentially, and demonstrates how it is possible to tune the activity and selectivity of the active species through the NO ligand structure.
- Sackville, Emma V.,Kociok-K?hn, Gabriele,Hintermair, Ulrich
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p. 3578 - 3588
(2017/10/03)
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- “Half-sandwich” Schiff-base Ir(III) complexes as anticancer agents
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A series of “half-sandwich” Schiff-base Ir(III) complexes were synthesized and investigated for their in vitro activities against the leukemia K562 cell line. These compounds demonstrated antiproliferative activities against K562 cells with IC50 values of 0.26–4.77 μM. In particular, compound 10c showed cytotoxicity against five cancer cell lines/sublines and stronger activities than cisplatin in K562, K562/A02, MCF-7, MCF-7/ADM, and A549 cells. Mechanism studies illustrated that compound 10c increased the level of reactive oxygen species and induced apoptosis of K562 cells. This compound effectively decreased the mitochondrial membrane potential and the protein level of Bcl-2. It also increased the protein levels of Bax, caspase-3, and caspase-9, and led to release of cytochrome c in K562 cells, indicating that the apoptosis induced by compound 10c was mediated by the intrinsic mitochondria apoptosis pathway.
- Mou, Ze-dong,Deng, Ning,Zhang, Feng,Zhang, Jiaying,Cen, Juan,Zhang, Xia
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- Promotion of iridium complex catalysts for HCOOH dehydrogenation by trace oxygen
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Ir complexes are important homogeneous catalysts for formic acid (FA) dehydrogenation. This paper reports that the activity of Ir complexes can be greatly improved through the activation by trace amounts of oxygen. After activation the activity of the heterodinuclear Ir–Ru catalyst increased 18-fold whereas for the mononuclear catalyst a 23-fold increase was observed. Oxygen is the key factor for the activation. But an excessive concentration of oxygen has a negative effect on the activity. There is an optimal concentration of H2O2 for the activation of Ir complex catalysts in HCOOH dehydrogenation. A very low concentration of oxygen (2.4 × 10–6 M) is needed for the activation of the heterodinuclear Ir–Ru catalyst while the mononuclear catalyst requires the presence of oxygen in a much higher concentration (290 × 10–6 M). From the results of the study it can be inferred that the activation of complex catalysts is due to the interplay of chemical and structural changes. These findings may be helpful in the attempts to improve the catalytic activity of homogeneous catalysts, which are widely used in formic acid dehydrogenation, CO2 reduction and in other processes. In addition, this paper indicates that iridium complexes are excellent catalysts for the direct synthesis of H2O2 from the H2 and O2.
- Zhan, Yulu,Shen, Yangbin,Du, Ying,Yue, Baohua,Zhou, Xiaochun
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p. 499 - 505
(2017/10/11)
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- Highly active iridium catalyst for hydrogen production from formic acid
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Formic acid (FA) dehydrogenation has attracted a lot of attentions since it is a convenient method for H2 production. In this work, we designed a self-supporting fuel cell system, in which H2 from FA is supplied into the fuel cell, and the exhaust heat from the fuel cell supported the FA dehydrogenation. In order to realize the system, we synthesized a highly active and selective homogeneous catalyst IrCp*Cl2bpym for FA dehydrogenation. The turnover frequency (TOF) of the catalyst for FA dehydrogenation is as high as 7150?h?1 at 50?°C, and is up to 144,000?h?1 at 90?°C. The catalyst also shows excellent catalytic stability for FA dehydrogenation after several cycles of test. The conversion ratio of FA can achieve 93.2%, and no carbon monoxide is detected in the evolved gas. Therefore, the evolved gas could be applied in the proton exchange membrane fuel cell (PEMFC) directly. This is a potential technology for hydrogen storage and generation. The power density of the PEMFC driven by the evolved gas could approximate to that using pure hydrogen.
- Du, Ying,Shen, Yang-Bin,Zhan, Yu-Lu,Ning, Fan-Di,Yan, Liu-Ming,Zhou, Xiao-Chun
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p. 1746 - 1750
(2017/07/27)
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- Evolution of rhodium(III) and iridium(III) chelates as metallonucleases
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Half sandwich cationic mononuclear rhodium(III) and iridium(III) complexes [(η5-C5Me5)M(L)Cl]Cl·2H2O where L = dipyridylamine (dpa) (M = Rh, 1 and Ir, 2) and dipyridylketone (dpk) (M = Rh, 3 and Ir, 4) have been synthesized and characterized. The structure of a representative complex (1) was authenticated by single crystal X-ray diffraction analysis. Complexes 1–4 have been fully characterized by various physicochemical techniques, namely elemental analysis, spectral (IR, 1H, NMR, UV–Vis), electrochemical studies (cyclic voltammetry (CV) and differential pulse voltammetry (DPV)). Notably, the UV absorption spectral titrations of the synthesized complexes with DNA reveal that the complexes bind to calf thymus DNA (CT-DNA) through the intercalation mode. The DNA solution hydrodynamic volume (viscosity) measurements show that the interaction of the compounds with CT-DNA occurs by classical intercalation. A molecular docking study suggested intercalation between the synthesized compounds and nucleotide base pairs. Cyclic voltammetry studies of the complexes indicate irreversible oxidation and reduction potentials. A gel electrophoresis assay demonstrates the ability of the complexes to cleave pUC19 DNA. The antibacterial activities were assayed against selected Gram(?ve) and Gram(+ve) microorganisms. The cytotoxic properties of the metal complexes have been evaluated using a brine shrimp lethality bioassay. The results suggest that the binding affinity of 1–4 lies in the order 1 > 4?> 2 > 3.
- Vekariya, Pankajkumar A.,Karia, Parag S.,Vaghasiya, Jayraj V.,Soni, Saurabh,Suresh,Patel, Mohan N.
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- Transition metal diamine complexes with antimicrobial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA)
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Pentaalkylcyclopentadienyl (Cp?R) iridium (Ir) and cobalt (Co) 1,2-diamine complexes were synthesized. Susceptibility of Staphylococcus aureus and recent patient methicillin-resistant S. aureus (MRSA) isolates to the transition metal-diamine complexes were measured by broth microdilution and reported as the MIC and MBC. Hemolytic activities of the transition metal-complexes as well as toxicity toward Vero cells were also measured. The transition metal complex of Cp?RIr with cis-1,2-diaminocyclohexane, had strong antibiotic activity against S. aureus and MRSA (MIC = 4 μg mL-1, MBC = 8 μg mL-1) strains and killed 99% of S. aureus cells in 6 hours. Stronger antibiotic activity was associated with the presence of octyl linked to the cyclopentadienyl group and cyclohexane as the diamine backbone. Activity was greatly diminished by tri- or tetramethylation of the nitrogen of the diamine. A cyclopentadienylcobalt complex of cis-1,2-diaminocyclohexane also showed significant anti-microbial activity against both S. aureus and MRSA strains. The absence of hemolytic activity, Vero cell cytotoxicity and the significant anti-microbial activity of several members of the family of compounds reported suggest this is an area worth further development.
- Karpin,Morris,Ngo,Merola,Falkinham Iii
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p. 1471 - 1478
(2015/08/18)
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- Structural diversity of bimetallic rhodium and iridium half sandwich dithiolato complexes
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The synthesis of a range of rhodium(iii) and iridium(iii) half sandwich complexes with aryl dithiolato ligands of varying geometry and flexibility are reported. These include dinuclear [CpM(S-R-S)]2 complexes 3b and 4b, M = Rh, Ir; S-R-S = naphthalene-1,8-dithiolate (b) and four dinuclear complexes bearing bridging dithiolate ligands [(CpM)2(μ2-Cl)(μ2-S-R-S)]Cl 3c, 4c, 5b, 6b, M = Rh, Ir; S-R-S = naphthalene-1,8-dithiolate (b) or acenaphthene-5,6-dithiolate (c). The introduction of a less rigid biphenyl dithiolate backbone resulted in the tetranuclear dicationic complex [(CpRh)4(S-R-S)3]Cl2 (3d), S-R-S = biphenyl-2,2′-dithiolate (d) with dithiolate ligands in two different bridging modes. All new complexes were fully characterised by multinuclear NMR, IR, Raman and MS spectroscopy and single crystal X-ray diffraction.
- Nejman, Phillip S.,Morton-Fernandez, Brian,Moulding, David J.,Athukorala Arachchige, Kasun S.,Cordes, David B.,Slawin, Alexandra M. Z.,Kilian, Petr,Woollins, J. Derek
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supporting information
p. 16758 - 16766
(2015/10/05)
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- Alkylation of Amines with Alcohols and Amines by a Single Catalyst under Mild Conditions
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An efficient catalytic system for the alkylation of amines with either alcohols or amines under mild conditions has been developed, using cyclometallated iridium complexes as catalysts. The method has broad substrate scope, allowing for the synthesis of a diverse range of secondary and tertiary amines with good to excellent yields. By controlling the ratio of substrates, both mono- and bis-alkylated amines can be obtained with high selectivity. In particular, methanol can be used as the alkylating reagent, affording N-methylated products selectively. A strong solvent effect is observed for the reaction.
- Zou, Qingzhu,Wang, Chao,Smith, Jen,Xue, Dong,Xiao, Jianliang
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supporting information
p. 9656 - 9661
(2015/06/30)
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- A monolith immobilised iridium Cp catalyst for hydrogen transfer reactions under flow conditions
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An immobilised iridium hydrogen transfer catalyst has been developed for use in flow based processing by incorporation of a ligand into a porous polymeric monolithic flow reactor. The monolithic construct has been used for several redox reductions demonstrating excellent recyclability, good turnover numbers and high chemical stability giving negligible metal leaching over extended periods of use.
- Rojo, Maria Victoria,Guetzoyan, Lucie,Baxendale, Ian. R.
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p. 1768 - 1777
(2015/02/19)
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- Catalytic acceptorless dehydrogenative coupling of arylhydrazines and alcohols for the synthesis of arylhydrazones
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The direct synthesis of arylhydrazones via catalytic acceptorless dehydrogenative coupling of arylhydrazines and alcohols has been accomplished. More importantly, complete selectivity for arylhydrazones and none of the N-alkylated byproducts were generated in this process, which exhibit new potential and provide a new horizon for the development of catalytic acceptorless dehydrogenative coupling reactions.
- Li, Feng,Sun, Chunlou,Wang, Nana
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p. 8031 - 8039
(2015/03/18)
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- Efficient and rapid synthesis of chlorido-bridged half-sandwich complexes of ruthenium, rhodium, and iridium by microwave heating
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The dinuclear complexes [(p-cymene)RuCl2]2 and [(cyclopentadienyl)MCl2]2 (M = Ru, Rh, Ir) are important starting materials in organometallic chemistry. The standard synthesis of these complexes involves heating of an alcoholic solution of RuIII, Rh III, or IrIII salts with precursors of the π-ligands for several hours under reflux. Microwave heating allows these complexes to be obtained within a few minutes without compromising the yields. Furthermore, the microwave-assisted syntheses require less solvent and, in some cases, lower amounts of ligand precursors. The important organometallic starting materials [(p-cymene)RuCl2]2 and [(cyclopentadienyl)MCl 2]2 (M = Ru, Rh, Ir) can be obtained by microwave heating. This methodology shortens their synthesis times from several hours to a few minutes. Copyright
- Toennemann, Justus,Risse, Julie,Grote, Zacharias,Scopelliti, Rosario,Severin, Kay
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p. 4558 - 4562
(2013/09/23)
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- BIMETALLIC CATALYSTS FOR CO2 HYDROGENATION AND H2 GENERATION FROM FORMIC ACID AND/OR SALTS THEREOF
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The invention relates to a ligand that may be used to create a catalyst including a coordination complex is formed by the addition of two metals; Cp, Cp* or an unsubstituted or substituted π-arene; and two coordinating solvent species or solvent molecules. The bimetallic catalyst may be used in the hydrogenation of C02 to form formic acid and/or salts thereof, and in the dehydrogenation of formic acid and/or salts thereof to form H2 and C02.
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Page/Page column 26
(2013/03/28)
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- Cyclometalated iridium complexes for transfer hydrogenation of carbonyl groups in water
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Cyclometalated iridium complexes are shown to be excellent catalysts for transfer hydrogenation of carbonyl compounds in water using formate as a hydrogen source. A wide range of ketones and aldehydes have been reduced at 0.05% catalyst loading with no need for any organic solvents. Solution pH is found to play a critical role, with acidic conditions needed for fast transfer hydrogenation.
- Wei, Yawen,Xue, Dong,Lei, Qian,Wang, Chao,Xiao, Jianliang
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p. 629 - 634
(2013/04/10)
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- Highly efficient transformation of levulinic acid into pyrrolidinones by iridium catalysed transfer hydrogenation
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Levulinic acid (LA) is transformed into pyrrolidinones via iridium-catalysed reductive amination using formic acid as the hydrogen source under aqueous conditions. The catalytic system is the most active and performs under the mildest conditions ever reported for the reductive amination of LA.
- Wei, Yawen,Wang, Chao,Jiang, Xue,Xue, Dong,Li, Jia,Xiao, Jianliang
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supporting information
p. 5408 - 5410
(2013/07/05)
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- MONONUCLEAR METAL COMPLEX, HYDROGENATION REDUCTION CATALYST, DEHYDROGENATION CATALYST, METHOD FOR PRODUCING HYDROGENATION REDUCTION PRODUCT, METHOD FOR PRODUCING HYDROGEN (H2), AND METHOD FOR PRODUCING DEHYDROGENATION REACTION
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The present invention provides: a mononuclear metal complex that has high catalytic activity and can be used as a hydrogenation reduction catalyst that allows efficient hydrogenation reduction of a substance to be reduced; a tautomer or stereoisomer thereof; or a salt thereof. Provided is the mononuclear metal complex represented by the following formula (1), a tautomer or stereoisomer thereof; or a salt thereof. In the formula (1), Ar1 is an aromatic anionic ligand or an aromatic ligand, or is not present, Ar2 is a ligand having aromaticity and may or may not be substituted, and when Ar2 is substituted, the number of substituents may be one or more, M is an atom or ion of a transition metal, A1 and A2 are both carbon atoms, or one of A1 and A2 is a carbon atom and the other is a nitrogen atom, Y is an anionic group or a cationic group, or is not present, L is any ligand or is not present, and m is a positive integer, 0, or a negative integer.
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Page/Page column 27
(2013/02/27)
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- The mechanism of N-vinylindole formation via tandem imine formation and cycloisomerisation of o-ethynylanilines
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The reaction of 2-(2-phenylethynyl)aniline with acetone in presence of [IrCp*Cl2]2 has previously been found to yield a vinyl indole derivative and not the indole expected to form following a hydroamination reaction. Experimental dat
- Kennedy, Danielle F.,Nova, Ainara,Willis, Anthony C.,Eisenstein, Odile,Messerle, Barbara A.
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p. 10296 - 10304
(2010/03/25)
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- Organometallic dithiolene complexes of benzenedithiolate analogues with π-coordinating and π-interacting Cp* ligand
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Organometallic dithiolene complexes, which were formulated as [Cp*M(dcbdt)] and [Cp*M(dcdmp)] (M = Co, Rh, Ir; Cp* = η5-pentamethylcyclopentadienyl, dcbdt = 4,5-dicyanobenzene-1,2-dithiolate, dcdmp = 2,3-dicyano-5,6-dimercaptopyrazine) were pre
- Nomura, Mitsushiro,Tsukano, Eriko,Fujita-Takayama, Chikako,Sugiyama, Toru,Kajitani, Masatsugu
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p. 3116 - 3124
(2009/12/08)
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- Carbon-sulfur bond cleavage of methyl-substituted thiophenes with iridium(III)
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Reaction of [Cp*IrHCl]2 (Cp* = η5- C5Me5) with 2-methylthiophene and 2,5-dimethylthiophene at 120 °C in the presence of H2 results in the cleavage of the thiophene carbon-sulfur bond(s). In both cases
- Grochowski, Matthew R.,Brennessel, William W.,Jones, William D.
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p. 2661 - 2667
(2009/09/26)
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- Vapor pressure of some volatile iridium(I) compounds with carbonyl, acetylacetonate and cyclopentadienyl ligands
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Volatile compounds of iridium(I): (acetylacetonato)(1,5-cyclooctadiene) iridium(I) Ir(acac)(cod), (methylcyclopentadienyl) (1,5-cyclooctadiene) iridium(I) Ir(Cp')(cod), (pentamethylcyclopentadienyl)(dicarbonyl) iridium(I) Ir(Cp*)(CO)2 and (acet
- Morozova,Semyannikov,Trubin,Stabnikov,Bessonov,Zherikova,Igumenov
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p. 261 - 266
(2009/05/06)
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