Search results for "Iridium"
showing 10 items of 296 documents
Electrochemical detection of nitric oxide in plant cell suspensions
2016
SPE IPM UB; Nitric oxide is a hydrophobic radical acting as a physiological mediator in plants. Because of its unique properties, the detection of NO in plant tissues and cell suspensions remains a challenge. For this purpose, several techniques are used, each having certain advantages and limitations such as interferences with other species, questionable sensitivity, and/or selectivity or ex situ measurement. Here we describe a very attractive approach for tracking NO in plant cell suspensions using a NO-sensitive homemade platinum/iridium-based electrochemical microsensor. This method constitutes the absolute real-time proof of the production of free NO in physiological conditions.
Phase stability and electronic structure of iridium metal at the megabar range
2019
[EN] The 5d transition metals have attracted specific interest for high-pressure studies due to their extraordinary stability and intriguing electronic properties. In particular, iridium metal has been proposed to exhibit a recently discovered pressure-induced electronic transition, the so-called core-level crossing transition at the lowest pressure among all the 5d transition metals. Here, we report an experimental structural characterization of iridium by x-ray probes sensitive to both long- and short-range order in matter. Synchrotron-based powder x-ray diffraction results highlight a large stability range (up to 1.4 Mbar) of the low-pressure phase. The compressibility behaviour was char…
Tuning the photophysical properties of cationic iridium(iii) complexes containing cyclometallated 1-(2,4-difluorophenyl)-1H-pyrazole through function…
2012
Four new heteroleptic iridium(III) complexes in the family [Ir(dfppz)(2)((NN)-N-boolean AND)](+), where Hdfppz = 1-(2,4-difluorophenyl)-1H-pyrazole and (NN)-N-boolean AND = 6-phenyl-2,2'-bipyridine (1), 4,4'-(di-tert-butyl)-6-phenyl-2,2'-bipyridine (2), 4,4'-(di-tert-butyl)-6,6'-diphenyl-2,2'-bipyridine (3) and 4,4'-bis(dimethylamino)-2,2'-bipyridine (4), have been synthesized as the hexafluoridophosphate salts and fully characterized. Single crystal structures of ligand 3 and the precursor [Ir-2(dfppz)(4)(mu-Cl)(2)] have been determined, along with the structures of the complexes 4{[Ir(dfppz)(2)(1)][PF6]}center dot 3CH(2)Cl(2), [Ir(dfppz)(2)(3)][PF6]center dot CH2Cl2 and [Ir(dfppz)(2)(4)][…
[Ir(C^N)2(N^N)]+ emitters containing a naphthalene unit within a linker between the two cyclometallating ligands
2016
The synthesis of four cyclometallated [Ir(C^N) 2 (N^N)][PF 6 ] compounds in which N^N is a substituted 2,2’- -bipyridine (bpy) ligand and the naphthyl-centred ligand 2,7-bis(2-(2-(4-(pyridin-2-yl)phenoxy)ethoxy) ethoxy)naphthalene provides the two cyclometallating C^N units is reported. The iridium( III ) complexes have been characterized by 1 H and 13 C NMR spectroscopies, mass spectrometry and elemental analysis, and their electrochemical and photophysical properties are described. Comparisons are made with a model [Ir(ppy) 2 (N^N)][PF 6 ] compound (Hppy = 2-phenylpyridine). The complexes containing the naphthyl-unit exhibit similar absorption spectra and excitation at 280 nm leads to an …
Fetal dose measurements and shielding efficiency assessment in a custom setup of (192)Ir brachytherapy for a pregnant woman with breast cancer.
2015
To assess the radiation dose to the fetus of a pregnant patient undergoing high-dose-rate (HDR) (192)Ir interstitial breast brachytherapy, and to design a new patient setup and lead shielding technique that minimizes the fetal dose.Radiochromic films were placed between the slices of an anthropomorphic phantom modeling the patient. The pregnant woman was seated in a chair with the breast over a table and inside a leaded box. Dose variation as a function of distance from the implant volume as well as dose homogeneity within a representative slice of the fetal position was evaluated without and with shielding.With shielding, the peripheral dose after a complete treatment ranged from 50 cGy at…
A Supramolecularly-Caged Ionic Iridium(III) Complex Yielding Bright and Very Stable Solid-State Light-Emitting Electrochemical Cells
2008
A new iridium(III) complex showing intramolecular interligand pi-stacking has been synthesized and used to improve the stability of single-component, solid-state light-emitting electrochemical cell (LEC) devices. The pi-stacking results in the formation of a very stable supramolecularly caged complex. LECs using this complex show extraordinary stabilities (estimated lifetime of 600 h) and luminance values (average luminance of 230 cd m-2) indicating the path toward stable ionic complexes for use in LECs reaching stabilities required for practical applications.
1,2‐Benzothiazine Derivatives from Sulfonimidamides by Metal‐Catalyzed Annulation Reactions in Solution and under Solvent‐Free Mechanochemical Condit…
2021
Advanced synthesis & catalysis (2021). doi:10.1002/adsc.202001505 special issue: "Hot Topic: C-H Activation"
Lowest triplet excited states of a novel heteroleptic iridium(III) complex and their role in the emission colour
2009
Abstract The [Ir(ppy-F 2 ) 2 Me 4 phen] +1 complex, where ppy-F 2 is 2-(2′,4′-fluorophenyl)pyridine and Me 4 phen is 3,4,7,8-tetramethyl-1,10-phenanthroline, has been theoretically investigated by means of DFT calculations. The molecular and electronic properties calculated for [Ir(ppy-F 2 ) 2 Me 4 phen] +1 are compared with those obtained for the simpler [Ir(ppy)(bpy)] +1 complex. The introduction of fluorine substituents in the ppy ligands and the use of phenanthroline instead of 2,2′-bipyridine as the diimine ligand increase the HOMO–LUMO energy gap and blue-shift the emission colour. The phenanthroline ligand causes the appearance of two nearly-degenerate LUMO orbitals of different symm…
The selective synthesis of metallanucleosides and metallanucleotides: a new tool for the functionalization of nucleic acids.
2012
Nucleobases team up: the efficient and selective preparation of purine-derived metallanucleosides, metallanucleotides, and metalladinucleotides having M-C bonds (M=Ir(III), Rh(III)) is reported for the first time. The results presented may be applied to the synthesis of functionalized nucleic acids, or DNA/RNA-modified segments.
Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands.
2017
A series of bis-cyclometalated iridium(III) complexes of general formula [Ir(ppy)2(N∧N)][PF6] (ppy− = 2-phenylpyridinate; N∧N = 2-(1H-imidazol-2-yl)pyridine (1), 2-(2-pyridyl)benzimidazole (2), 1-methyl-2-pyridin-2-yl- 1H-benzimidazole (3), 2-(4′-thiazolyl)benzimidazole (4), 1- methyl-2-(4′-thiazolyl)benzimidazole (5)) is reported, and their use as electroluminescent materials in light-emitting electrochemical cell (LEC) devices is investigated. [2][PF6] and [3][PF6] are orange emitters with intense unstructured emission around 590 nm in acetonitrile solution. [1][PF6], [4][PF6], and [5][PF6] are green weak emitters with structured emission bands peaking around 500 nm. The different photoph…