- Evaluation of anticancer effect in vitro and in vivo of iridium(III) complexes on gastric carcinoma SGC-7901 cells. [Journal Article]
- EJEur J Med Chem 2019 Jun 05; 178:401-416
- This work mainly introduces the synthesis and characterization of three iridium(III) complexes [Ir(ppy)2(adppz)](PF6) (Ir-1), [Ir(bzq)2(addpz)](PF6) (Ir-2) and [Ir(piq)2(adppz)](PF6) (Ir-3). The comp…
This work mainly introduces the synthesis and characterization of three iridium(III) complexes [Ir(ppy)2(adppz)](PF6) (Ir-1), [Ir(bzq)2(addpz)](PF6) (Ir-2) and [Ir(piq)2(adppz)](PF6) (Ir-3). The complexes are more cytotoxic than cisplatin against tumor cell lines such as SGC-7901, A549, HeLa, Eca-109, HepG2 and BEL-7402. The toxicity test results indicated that complexes Ir-1, Ir-2 and Ir-3 can effectively inhibit the cell growth of SGC-7901 cells, and the measured IC50 values are 1.8 ± 0.4, 1.6 ± 0.3 and 0.8 ± 0.1 μM, respectively. AO/EB staining and flow apoptosis confirmed that SGC-7901 cells were caused apoptosis after being treated with the complexes. Along with the increase of endogenous ROS and Ca2+ levels, mitochondrial membrane potential collapse and massive release of cytochrome c, it is fully demonstrated that these complexes induce apoptosis through ROS-mediated mitochondrial pathway. At the same time, the complex Ir-3 is outstanding in the inhibition of tumor growth in vivo. Combined with the above results, it provides a favorable foundation for the future development of more effective anti-tumor drugs.
- Studies of anticancer activity in vitro and in vivo of iridium(III) polypyridyl complexes-loaded liposomes as drug delivery system. [Journal Article]
- EJEur J Med Chem 2019 Jun 04; 178:390-400
- Two iridium(III) polypyridyl complexes [Ir(ppy)2(HPIP)](PF6) (Ir-1), [Ir(ppy)2(BHPIP)](PF6) (Ir-2) and their liposomes Ir-1-Lipo and Ir-2-Lipo were synthesized and characterized by elemental analysis…
Two iridium(III) polypyridyl complexes [Ir(ppy)2(HPIP)](PF6) (Ir-1), [Ir(ppy)2(BHPIP)](PF6) (Ir-2) and their liposomes Ir-1-Lipo and Ir-2-Lipo were synthesized and characterized by elemental analysis, IR, 1H NMR and 13C NMR. The anticancer activity in vitro and in vivo was evaluated. The cytotoxic activity in vitro of the complexes and their liposomes Ir-1-Lipo and Ir-2-Lipo against cancer cells was investigated by MTT methods. Ir-1 and Ir-2 show no cytotoxic activity, while Ir-1-Lipo and Ir-2-Lipo exhibit high cytotoxic effect. The IC50 values range from 5.2 ± 0.8 to 22.3 ± 1.8 μM. The apoptosis, reactive oxygen species, the change of mitochondrial membrane potential, intracellular Ca2+ levels and a release of cytochrome c were investigated. The effect of Ir-1-Lipo and Ir-2-Lipo on microtubules was also explored. In the C57BL/6 mice model, Ir-1 only displays a tumor inhibitory rate of 23.21%, while lr-1-Lipo exhibits satisfactory in vivo antitumor efficacy with tumor inhibitory rate of 72.55%. This study demonstrates that complexes encapsulated in liposomes induce apoptosis in B16 through ROS-mediated lysosomal-mitochondria dysfunction, inhibition of polymerization of microtubules and induce cell cycle arrest at S phase.
- Formation of Amidinyl Radicals via Visible-Light-Promoted Reduction of N-Phenyl Amidoxime Esters and Application to the Synthesis of 2-Substituted Benzimidazoles. [Journal Article]
- JOJ Org Chem 2019 Jun 14
- We have developed a new method for the synthesis of 2-substituted benzimidazoles via amidinyl radicals generated by visible-light-promoted reduction of N-phenyl amidoxime esters in the presence of an…
We have developed a new method for the synthesis of 2-substituted benzimidazoles via amidinyl radicals generated by visible-light-promoted reduction of N-phenyl amidoxime esters in the presence of an iridium photocatalyst. This is the first report of the use of N-phenyl amidoxime esters as amidinyl radical precursors, and the first use of substituted benzene rings as amidinyl radical acceptors. This method overcomes the shortcomings of the traditional methods for synthesis of 2-substituted benzimidazoles, which require harsh reaction conditions, involve difficult-to-prepare substituted o-phenylenediamine substrates, and produce acidic waste.
- Complementary approaches to imaging sub-cellular lipid architectures in live bacteria using phosphorescent iridium complexes and Raman spectroscopy. [Journal Article]
- CChemistry 2019 Jun 13
- A family of three neutral iridium(III) tetrazolato complexes are investigated as bacterial imaging agents. The complexes offer a facile tuning of the emission colour from green (520 nm) to red (600 n…
A family of three neutral iridium(III) tetrazolato complexes are investigated as bacterial imaging agents. The complexes offer a facile tuning of the emission colour from green (520 nm) to red (600 nm) in aqueous media, while keeping the excitation wavelength unchanged. The three complexes do not inhibit the bacterial growth of Bacillus Cereus, used as a model in this study, and exhibit extremely fast cellular uptake. After a minute incubation time, the non-toxic complexes show sub-cellular localisation in spherical structures identified as lipid vacuoles. Confocal Raman imaging has been exploited for the first time on live bacteria, to provide direct and label-free mapping of the lipid-enriched organelles within B. cereus, complementing the use of luminescent probes. Examination of the Raman spectra not only confirmed the presence of lipophilic inclusions in B. cereus but offered additional information about their chemical composition, suggesting that the lipid vacuoles may contain polyhydroxybutyrate (PHB).
- Catalytic Decomposition of an Ionic Liquid Monopropellant Over Ir/Hexaaluminate Catalysts. [Journal Article]
- JNJ Nanosci Nanotechnol 2019 Dec 01; 19(12):7906-7910
- The aim of this study is to elucidate the influence of an iridium loading strategy over hexaaluminate on the catalytic performance during the decomposition of liquid monopropellants based on ammonium…
The aim of this study is to elucidate the influence of an iridium loading strategy over hexaaluminate on the catalytic performance during the decomposition of liquid monopropellants based on ammonium dinitramide (ADN). Powder-type and pellet-type Ir/hexaaluminate catalysts were prepared and their chemico-physical properties were characterized by N₂ adsorption, XRD, XRF, and SEM. There were considerable differences in the Ir amounts present on the surface according to the impregnation method employed. The catalytic activities of three types of Ir/hexaaluminate catalysts to decompose the ADN-based liquid monopropellant were compared using a semi-batch type of reactor. Pellet-type Ir/hexaaluminate catalyst, which formed hexaaluminate into a pellet and where iridium was impregnated during the last stage, showed the lowest onset temperature during the decomposition of the ADN-based liquid monopropellant, having the effect of lowering the decomposition onset temperature by around 60 °C compared to that without a catalyst. This was due to the pellet-type Ir/hexaaluminate having a larger surface area and a large number of Ir active sites on its surface.
- An iridium(III) complex/G-quadruplex ensemble for detection of ochratoxin A based on long-lifetime luminescent. [Journal Article]
- ABAnal Biochem 2019 Jun 11; 580:49-55
- A G-quadruplex-based platform has been developed for the time-resolved monitoring of ochratoxin A (OTA). The simple platform displays good sensitivity for OTA with a detection limit of 40 nM via stea…
A G-quadruplex-based platform has been developed for the time-resolved monitoring of ochratoxin A (OTA). The simple platform displays good sensitivity for OTA with a detection limit of 40 nM via steady-state emission spectroscopy. Notably, the platform showed a detection limit of 10.8 nM via time-resolved emission spectroscopy (TRES), which is about 4 times more sensitive than steady-state mode. Moreover, the probe showed excellent selectivity for OTA over other mycotoxins. Furthermore, OTA was successfully detected in actual herbal plant extracts samples. Our platform is the first to detect OTA using TRES to distinguish between the target signals versus the auto-fluorescence of real samples. This platform shows improved detection speed, accuracy and sensitivity with simple operation, low cost, and no requirement for complicated pre-processing.
- The status of radiation oncology (RO) teaching to medical students in Europe. [Journal Article]
- CTClin Transl Radiat Oncol 2019; 17:40-46
- CONCLUSIONS: RO teaching to medical students was not uniform in Europe. RO teaching during undergraduate education in Europe was undervalued, and its knowledge and learning tools could be broadened and updated in the core curricula of medical students.
- Utilization of Ternary Europium Complex for Organic Electroluminescent Devices and as a Sensitizer to Improve Electroluminescence of Red-Emitting Iridium Complex. [Journal Article]
- ICInorg Chem 2019 Jun 13
- Two new lanthanide complexes [Ln(hfaa)3(Py-Im)] [hfaa = hexafluoroacetylacetone, Py-Im = 2-(2-pyridyl)benzimidazole and Ln = Eu(III) (1) and Tb(III) (2)] were synthesized and characterized. An X-ray …
Two new lanthanide complexes [Ln(hfaa)3(Py-Im)] [hfaa = hexafluoroacetylacetone, Py-Im = 2-(2-pyridyl)benzimidazole and Ln = Eu(III) (1) and Tb(III) (2)] were synthesized and characterized. An X-ray crystal structure determination confirms that complex 1 is eight-coordinate with a distorted trigonal dodecahedral geometry. It shows typical vivid red Eu(III) emission in the solid state, in solution, and in a polymer matrix. The observed lifetime (τobs) of complex 1 in the solid state, in dichloromethane (DCM) solution, and in thin films is 833.01, 837.95, and 626.16-715.69 μs, respectively, with a photoluminescence quantum yield QEuL ≈ 33% in DCM solution. Complex 2 displays a yellowish-green emission in the solid state (τobs ≈ 36.99 μs), while a near white-light emission in solution (x; 0.2574: y; 0.3371) and in thin films. Therefore, it is a potential candidate for generating single-component white light-emitting materials for solid-state lighting applications. The kinetic scheme for modeling energy-transfer processes shows that the main donor state for 1 is the ligand triplet state (T1) and that energy transfer occurs to both the 5D1 (56.55%) and 5D0 (40.58%) levels. We fabricated a series of single- and double-layer organic light-emitting devices using complex 1. The luminance of the optimized double-layer electroluminescence (EL) device was 373 cd/m2 with very low turn-on voltage of ∼4.2 V. Complex 1 was further utilized as a sensitizer to improve the EL of a red-emitting iridium complex PQ2Ir(dpm) (PQ = phenylquinoly-N,C2', dpm = dipivaloylmethane). The codoped device achieved a maximum brightness and maximum current efficiency (ηc) of 93 224 cd/m2 and 36.38 cd/A, respectively.
- Synthesis of Arylacetaldehydes by Iridium-Catalyzed Arylation of Vinylene Carbonate with Arylboronic Acids. [Journal Article]
- ACAngew Chem Int Ed Engl 2019 Jun 13
- One-step synthesis of arylacetaldehydes by carbon-carbon bond formation between formylmethyl and aryl groups has been realized by the reaction of vinylene carbonate with arylboronic acids in the pres…
One-step synthesis of arylacetaldehydes by carbon-carbon bond formation between formylmethyl and aryl groups has been realized by the reaction of vinylene carbonate with arylboronic acids in the presence of an iridium/bisphosphine catalyst and a catalytic amount of tetrahydroxydiboron.
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- Using coligands to gain mechanistic insight into iridium complexes hyperpolarized with para-hydrogen. [Journal Article]
- CSChem Sci 2019 May 28; 10(20):5235-5245
- We report the formation of a series of novel [Ir(H)2(IMes)(α-13C2-carboxyimine)L] complexes in which the identity of the coligand L is varied. When examined with para-hydrogen, complexes in which L i…
We report the formation of a series of novel [Ir(H)2(IMes)(α-13C2-carboxyimine)L] complexes in which the identity of the coligand L is varied. When examined with para-hydrogen, complexes in which L is benzylamine or phenethylamine show significant 1H hydride and 13C2 imine enhancements and may exist in 13C2 singlet spin order. Isotopic labeling techniques are used to double 13C2 enhancements (up to 750-fold) and singlet state lifetimes (up to 20 seconds) compared to those previously reported. Exchange spectroscopy and Density Functional Theory are used to investigate the stability and mechanism of rapid hydrogen exchange in these complexes, a process driven by dissociative coligand loss to form a key five coordinate intermediate. When L is pyridine or imidazole, competitive binding to such intermediates leads to novel complexes whose formation, kinetics, behaviour, structure, and hyperpolarization is investigated. The ratio of the observed PHIP enhancements were found to be affected not only by the hydrogen exchange rates but the identity of the coligands. This ligand reactivity is accompanied by decoherence of any 13C2 singlet order which can be preserved by isotopic labeling. Addition of a thiol coligand proved to yield a thiol oxidative addition product which is characterized by NMR and MS techniques. Significant 870-fold 13C enhancements of pyridine can be achieved using the Signal Amplification By Reversible Exchange (SABRE) process when α-carboxyimines are used to block active coordination sites. [Ir(H)2(IMes)(α-13C2-carboxyimine)L] therefore acts as unique sensors whose 1H hydride chemical shifts and corresponding hyperpolarization levels are indicative of the identity of a coligand and its binding strength.