Search results for "Phosphore"
showing 10 items of 114 documents
Iridium(III) Complexes with Phenyl-tetrazoles as Cyclometalating Ligands
2014
Ir(II) cationic complexes with cyclometalating tetrazolate ligands were prepared for the first time, following a two-step strategy based on (i) a silver-assisted cyclometalation reaction of a tetrazole derivative with IrCl3 affording a bis-cyclometalated solvato-complex P ([Ir(ptrz)(2)(CH3CN)(2)](+), Hptrz = 2-methyl-5-phenyl-2H-tetrazole); (ii) a substitution reaction with five neutral ancillary ligands to get [Ir(ptrz)(2)L](+), with L = 2,2'-bypiridine (1), 4,4'-di-tert-butyl-2,2'-bipyridine (2), 1,10-phenanthroline (3), and 2-(1-phenyl-1H-1,2,3-triazol-4-yl)pyridine (4), and [Ir(ptrz)(2)L-2](+), with L = tertbutyl isocyanide (5). X-ray crystal structures of P, 2, and 3 were solved. Elect…
Ship-in-a-Bottle Synthesis of a Large Guest Occupying Two Y Zeolite Neighbour Supercages: Characterisation and Photocatalytic Activity of the Encapsu…
2003
In a series of papers we reported the ship-in-a-bottle synthesis, photochemical properties and photocatalytic applications of 2,4,6-triphenylpyrylium cation (TP ) encapsulated inside the cavities of large pore zeolites Y and Beta. 2] The identity of encapsulated TP was then confirmed spectroscopically, particularly by the match of the IR spectra of the encapsulated organic material and that of the tetrafluoroborate solid of TP (TPBF4). In addition, the electrochemical response of zeolite Y encapsulated TP (TP@Y) consisted of a reversible single reduction process taking place at the same redox potential as that measured for TPBF4 solutions. Encapsulation of TP has a dramatic influence on its…
An inconvenient influence of iridium(III) isomer on OLED efficiency.
2010
The recently reported heteroleptic cyclometallated iridium(III) complex [Ir(2-phenylpyridine)(2)(2-carboxy-4-dimethylaminopyridine)] N984 and its isomer N984b have been studied more in detail. While photo- and electrochemical properties are very similar, DFT/TDDFT calculations show that the two isomers have different HOMO orbital characteristics. As a consequence, solution processed OLEDs made using a mixture of N984 and isomer N984b similar to vacuum processed devices show that the isomer has a dramatic detrimental effect on the performances of the device. In addition, commonly used thermogravimetric analysis is not suitable for showing the isomerization process. The isomer could impact pe…
Ilgstošas fosforescences dizains karbazola atvasinājumos
2020
Ilgstošas fosforescences dizains karbazola atvasinājumos. Mazarevičs A., zinātniskie vadītāji Mg. chem. Leduskrasts K., Prof., Dr. chem. Sūna E. Bakalaura darbs, 62 lapaspuse, 55 attēli, 10 tabula, 42 literatūrās avoti, 4 pielikumi. Latviešu valodā. Literatūras apskatā analizēta luminiscence un fosforescence. Iekļauti organiskās fosforescences iegūšanas piemēri izmantojot kristalizāciju, smagā atoma efektu, starpmolekulāru un iekšmolekulāru mijiedarbību veidošanu kā arī nedalīta elektronu pāra vai karbonilgrupas ievadīšanu molekulā. Rezultātu izvērtējumā aprakstīta sintezēto savienojumu iegūšana, analizētas to luminiscentās īpašības, kā arī apskatīti rentgenstruktūras attēli no sintezētajie…
Xanthone-photosensitized detoxification of the veterinary anthelmintic fenbendazole
2013
Fenbendazole (1) is a common veterinary anthelmintic, toxic to water living microorganisms. Fluorescence quantum yields of 1 were found to be 0.11 in acetonitrile, 0.068 in methanol, 0.034 in cyclohexane, and 0.013 in water. The singlet excited state energy was ca. 96 kcal mol(-1) in all solvents. The phosphorescence spectrum of 1 in ethanol at 77 K displayed a maximum at 450 nm, leading to a triplet energy of 75 kcal mol(-1). Experimental excited state energies agree well with the results of OFT calculations at the time-dependent B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level. Laser flash photolysis (LFP) of 1 at 266 nm led to transients absorbing in the 300-700 nm range, ascribed to radical cat…
Near-IR to Near-IR Upconversion Luminescence in Molecular Chromium Ytterbium Salts
2020
Abstract Upconversion photoluminescence in hetero‐oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex ions was developed that exhibits excitation‐power density‐dependent cooperative sensitization of the chromium‐centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2→2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric ox…
Restitution de l’atelier 1 : Services écosystémiques recherchés relatifs aux cycles C,N ,P
2013
Coopération entre des bactéries solubilisatrices de phosphate et le champignon mycorhizien à arbuscule Rhizophagus irregularis dans la nutrition phos…
2019
National audience; Le phosphore est un élément essentiel pour le développement des plantes. Néanmoins, la majorité des ions phosphate est incorporée dans des structures organiques (Po) et inorganiques (Pi) insolubles qui rende cet élément très peu disponible pour les plantes et en particulier pour la pomme de terre (Solanum tuberosum). Dans les sols, le phytate (molécule de réserve phosphatée des plantes), est une source essentielle. Pour accéder au phosphate, les plantes ont développé des symbioses mutualistes à bénéfices réciproques avec des microorganismes de la rhizosphère capables d’extraire le P. Dans ce contexte, les objectifs de cette étude étaient de i) déterminer si la disponibili…
Density-functional tight-binding modeling of electromechanics of phosphorene
2018
Single-layer black phosphorus or phosphorene is a two-dimensional material made from a puckered honeycomb structure. It is a semiconductor with a tunable band gap and both its mechanical and electronic properties are highly asymmetric because of the puckering. Recently there has been numerous computational studies and some experimental works trying to bring deeper understanding about this relatively new 2D material. In this study we simulate phosphorene using computationally low-cost density functional tight-binding (DFTB) method to see how stretching, shearing and bending affect its electronic properties. The band structure analysis shows that there is a relation between shearing and bendi…
Structure and luminescence properties of supramolecular polymers of amphiphilic aromatic thioether–peptide conjugates in water
2019
We present the preparation of luminophore–peptide conjugates that self-assemble into supramolecular polymers in neutral buffer. To this end, we have prepared a small library of six conjugates with varying substitution patterns of the aromatic thioethers, as well as varying amino acid sequences. The latter have allowed us to tune the thermodynamic driving force for self-assembly and probe their photoluminescent properties either in the monomeric or polymeric state, while fully avoiding selective solvent techniques or organic solvent mixtures. All of the supramolecular structures were characterised with transmission electron microscopy, circular dichroism measurements, as well as steady-state…