12354-84-6Relevant articles and documents
Transition metal diamine complexes with antimicrobial activity against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA)
Karpin,Morris,Ngo,Merola,Falkinham Iii
, p. 1471 - 1478 (2015)
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.
Promotion of iridium complex catalysts for HCOOH dehydrogenation by trace oxygen
Zhan, Yulu,Shen, Yangbin,Du, Ying,Yue, Baohua,Zhou, Xiaochun
, p. 499 - 505 (2017)
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.
Half-Sandwich Iridium and Ruthenium Complexes: Effective Tracking in Cells and Anticancer Studies
Li, Juanjuan,Guo, Lihua,Tian, Zhenzhen,Zhang, Shumiao,Xu, Zhishan,Han, Yali,Li, Ruixia,Li, Yan,Liu, Zhe
, p. 13552 - 13563 (2018)
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.
Half sandwich platinum group metal complexes of thiourea derivative ligands with benzothiazole moiety possessing anti-bacterial activity and colorimetric sensing: Synthesis and characterisation
Shadap, Lathewdeipor,Diamai, Siewdorlang,Banothu, Venkanna,Negi,Adepally, Uma,Kaminsky, Werner,Kollipara, Mohan Rao
, p. 44 - 54 (2019)
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.
Organometallic dithiolene complexes of benzenedithiolate analogues with π-coordinating and π-interacting Cp* ligand
Nomura, Mitsushiro,Tsukano, Eriko,Fujita-Takayama, Chikako,Sugiyama, Toru,Kajitani, Masatsugu
, p. 3116 - 3124 (2009)
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
Lysosomal-targeted anticancer half-sandwich iridium(III) complexes modified with lonidamine amide derivatives
Xie, Yongkang,Zhang, Shumiao,Ge, Xingxing,Ma, Wenli,He, Xiaolin,Zhao, Yao,Ye, Juan,Zhang, Hongmin,Wang, Anwei,Liu, Zhe
, (2020)
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.
Synthesis, characterization and chemosensitivity studies of half-sandwich ruthenium, rhodium and iridium complexes containing к1(S) and к2(N,S) aroylthiourea ligands
Lapasam, Agreeda,Hussain, Omar,Phillips, Roger M.,Kaminsky, Werner,Kollipara, Mohan Rao
, p. 272 - 280 (2019)
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.
Ligand Tuning in Pyridine-Alkoxide Ligated Cp?IrIII Oxidation Catalysts
Sackville, Emma V.,Kociok-K?hn, Gabriele,Hintermair, Ulrich
, p. 3578 - 3588 (2017)
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.
Highly active iridium catalyst for hydrogen production from formic acid
Du, Ying,Shen, Yang-Bin,Zhan, Yu-Lu,Ning, Fan-Di,Yan, Liu-Ming,Zhou, Xiao-Chun
, p. 1746 - 1750 (2017)
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.
Novel half-sandwich iridium(iii) imino-pyridyl complexes showing remarkable: In vitro anticancer activity
Li, Juanjuan,Guo, Lihua,Tian, Zhenzhen,Tian, Meng,Zhang, Shumiao,Xu, Ke,Qian, Yuchuan,Liu, Zhe
, p. 15520 - 15534 (2017)
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.
