Search results for "Chela"
showing 10 items of 415 documents
New potential bimodal imaging contrast agents based on DOTA-like and porphyrin macrocycles
2011
A bifunctional chelator featuring (DO3A-AM)-Porphyrin units has been prepared. The high-field relaxivity of the Gd complex is similar to those of currently available contrast agents clearly showing that the first coordination sphere remains identical to the parent molecule [Gd(DO3A-AM)(H2O)], with one coordinated water molecule.
Approaching ‘kit-type’ labelling with 68Ga : the DATA chelators.
2015
The DATA chelators are a novel class of tri-anionic ligands based on 6-amino-1,4-diazepine-triacetic acid, which have been introduced recently for the chelation of (68)Ga. Compared with macrocyclic chelators based on the cyclen scaffold (i.e., DOTA, DO3A, and DO2A derivatives), DATA chelators undergo quantitative radiolabelling more rapidly and under milder conditions. In this study, a systematic evaluation of the labelling of four DATA chelators--DATA(M), DATA(P), DATA(Ph), and DATA(PPh)--with (68)Ga is presented. The results highlight the extraordinary potential of this new class of chelators for application in molecular imaging using (68)Ga positron emission tomography (PET).
NODAPA-OH and NODAPA-(NCS)n: Synthesis, 68Ga-radiolabelling and in vitro characterisation of novel versatile bifunctional chelators for molecular ima…
2008
This report concerns synthesis, (68)Ga-radiolabelling and stability data of 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-isothio-cyanatophenyl-acetic acid (NODAPA-NCS), 1,4,7-triazacyclononane-1-acetic acid-4,7-di-p-isothiocyanatophenyl-acetic acid (NODAPA-(NCS)(2)) and 1,4,7-triazacyclononane-1,4-diacetic acid-7-p-hydroxyphenyl-acetic acid (NODAPA-OH), versatile bifunctional chelators with potential for molecular imaging. Protein binding and exemplified conjugation are also reported.
Calix[4]arenes as Selective Extracting Agents. An NMR Dynamic and Conformational Investigation of the Lanthanide(III) and Thorium(IV) Complexes
2000
The lanthanide and Th4+ complexes with calix[4]arene ligands substituted either on the narrow or at the wide rim by four coordinating groups behave totally differently as shown by an NMR investigation of the dia- and paramagnetic complexes. Solutions of complexes were prepared by reacting anhydrous metal perchlorate salts with the ligands in dry acetonitrile (CAUTION). Relaxation time T1 titrations of acetonitrile solutions of Gd3+ by calixarenes indicate that ligands subsituted on the narrow rim form stable 1:1 complexes whether they feature four amide groups (1) or four phosphine oxide functions. In contrast, a ligand substituted by four (carbamoylmethyl)-diphenylphosphine oxide moieties …
Highly Photoluminescent Blue Ionic Platinum-Based Emitters
2019
New cycloplatinated N-heterocyclic carbene (NHC) compounds with chelate diphosphines (P^P) as ancillary ligands: [Pt(R-C^C*)(P^P)]PF6 (R = H, P^P = dppm (1A), dppe (2A), dppbz (3A); R = CN, P^P = dppm (1B), dppe (2B), dppbz (3B)) have been prepared from the corresponding starting material [{Pt(R-C^C*)(μ-Cl)}2] (R = H, A, R = CN, B) and fully characterized. The new compound A has been prepared by a stepwise protocol. The photophysical properties of 1A–3A and 1B–3B have been widely studied and supported by the time-dependent-density functional theory. These compounds show an efficient blue (dppe, dppbz) or cyan (dppm) emission in PMMA films (5 wt %), with photoluminescence quantum yield (PLQY…
Wide-Bite-Angle Diphosphine Ligands in Thermally Activated Delayed Fluorescent Copper(I) Complexes: Impact on the Performance of Electroluminescence …
2021
We report a series of seven cationic heteroleptic copper(I) complexes of the form [Cu(P^P)(dmphen)]BF4, where dmphen is 2,9-dimethyl-1,10-phenanthroline and P^P is a diphosphine chelate, in which the effect of the bite angle of the diphosphine ligand on the photophysical properties of the complexes was studied. Several of the complexes exhibit moderately high photoluminescence quantum yields in the solid state, with ΦPL of up to 35%, and in solution, with ΦPL of up to 98%. We were able to correlate the powder photoluminescence quantum yields with the % Vbur of the P^P ligand. The most emissive complexes were used to fabricate both organic light-emitting diodes and light-emitting electrochem…
Flux of protons released by wild type and ferritin over-expressor tobacco plants : effect of phosphorus and iron nutrition
2003
Abstract Tobacco ( Nicotiana tabacum ) plants over-expressing the iron storage protein ferritin, either in the cytoplasm or in the plastids, were grown under various P and Fe conditions. The crossed effects of both the genotypes and the environmental conditions on iron and chlorophyll concentrations in leaves, ferric reductase (EC 1.6.99.13) and plasmalemma H + -ATPase (EC 3.6.3.6) activities in roots, and fluxes of H + released by roots were determined. The increase in leaf Fe concentration observed in plants over-expressing ferritin was accompanied by an increase in root ferric reductase and H + -ATPase activities. Iron deficient conditions induced a decrease in Fe and chlorophyll concent…
β-Aminobutyric Acid (BABA)-Induced Resistance in Arabidopsis thaliana: Link with Iron Homeostasis
2014
International audience; Bêta-Aminobutyric acid (BABA) is a nonprotein amino acid inducing resistance in many different plant species against a wide range of abiotic and biotic stresses. Nevertheless, how BABA primes plant natural defense reactions remains poorly understood. Based on its structure, we hypothesized and confirmed that BABA is able to chelate iron (Fe) in vitro. In vivo, we showed that it led to a transient Fe deficiency response in Arabidopsis thaliana plants exemplified by a reduction of ferritin accumulation and disturbances in the expression of genes related to Fe homeostasis. This response was not correlated to changes in Fe concentrations, suggesting that BABA affects the…
Simultaneous determination of 4-nitroanisole, 4-nitrophenol, and 4-nitrocatechol by phase-sensitive ac polarography.
1977
Abstract Phase‐sensitive ac polarography was applied to the simultaneous quantitative determination of 4‐nitroanisole, 4‐nitrophenol and 4‐nitrocatechol in alkaline solutions. Certain experimental precautions are necessary to determine each compound in the presence of the other two. Thus, 4‐nitrocatechol is determined indirectly by forming a yellow ratio chelate with cupric ions, whereas 4‐nitroanisole is determined directly by the reduction waves of the nitro group. For the determination of 4‐nitrophenol, the interference by the simultaneously present 4‐nitrocatechol must be eliminated by masking it by the addition of magnesium ions. The method described permits a qualitative and quantitat…
Conventional Oxyanionic versus Monomer-Activated Anionic Copolymerization of Ethylene Oxide with Glycidyl Ethers: Striking Differences in Reactivity …
2022
Detailed understanding of the monomer distribution in copolymers is essential to tailor their properties. For the first time, we have been able to utilize in situ 1H NMR spectroscopy to monitor the monomer-activated anionic ring opening copolymerization (AROP) of ethylene oxide (EO) with a glycidyl ether comonomer, namely, ethoxy ethyl glycidyl ether (EEGE). We determine reactivity ratios and draw a direct comparison to conventional oxyanionic ROP. Surprisingly, the respective monomer reactivities differ strongly between the different types of AROP. Under conventional oxyanionic conditions similar monomer reactivities of EO and EEGE are observed, leading to random structures (rEO = 1.05 ± 0…