Search results for " LIGANDS"
showing 10 items of 196 documents
Transition metal ion induced hydrogelation by amino-terpyridine ligands
2014
Hydrogelation behavior of two amino-terpyridine ligands in the presence of divalent metal ions in water was studied in detail. The effect of ligand structure and different counter anions on the gel morphologies was also explored. peerReviewed
An Off-On-Off Fluorescent Sensor for pH Windows Based on the 13aneN4-Zn 2+ System
2016
International audience; The new ligand L was prepared and features a 13-membered tetraaza macrocyclic ring with a 1,8-naphthalimide fluorophore appended to a C atom of its backbone. The protonation constants of L as well as its complexation constants with Zn2+ ions were determined in 1:1 water/methanol solutions by potentiometric titrations. Fluorimetric pH titrations were performed with L alone and L in the presence of Zn2+ ions (1:1), and the species distributions (%) versus pH were compared. A window-shaped fluorescence trend was observed with pH for the L/Zn2+ system, which behaves as an off-on-off pH sensor. The on window is centred in the 6.5-7.5 pH range, in correspondence with the f…
Efficient ethylene polymerisation catalysis by a cationic benzyl hafnium complex containing pyrrolide-imine ligandsElectronic supplementary informati…
2002
A dibenzyl hafnium(IV) complex containing pyrrolide-imine chelate ligands was synthesized and investigated as an ethylene polymerisation catalyst.
Postęp badań w zakresie polimeryzacji olefin
2011
Na podstawie obszernego przeglądu literatury omówiono rozwój katalizatorów metaloorganicznych stosowanych w procesie polimeryzacji olefin z uwzględnieniem najnowszych badań w tym zakresie. Przedstawiono możliwości otrzymywania z ich udziałem produktów o różnej strukturze i właściwościach. Na tle postępu w technologii otrzymywania poliolefin scharakteryzowano wyniki najnowszych prac zespołu opolskiego, od wielu lat biorącego aktywny udział w badaniach nad opracowaniem i oceną właściwości katalitycznych kolejnych, nowych grup metaloorganicznych katalizatorów polimeryzacji i kopolimeryzacji olefin. Szczególną uwagę poświęcono katalizatorom zaliczanym do grupy układów postmetalocenowych z ligan…
Dynamics of weak interactions in the ligand layer of meta-mercaptobenzoic acid protected gold nanoclusters Au68(m-MBA)32 and Au144(m-MBA)40
2020
Atomically precise metal nanoclusters, stabilized and functionalized by organic ligands, are emerging nanomaterials with potential applications in plasmonics, nano-electronics, bio-imaging, nanocatalysis, and as therapeutic agents or drug carriers in nanomedicine. The ligand layer has an important role in modifying the physico-chemical properties of the clusters and in defining the interactions between the clusters and the environment. While this role is well recognized from a great deal of experimental studies, there is very little theoretical information on dynamical processes within the layer itself. Here, we have performed extensive molecular dynamics simulations, with forces calculated…
Nanoparticles as Contrast Agents for MRI of Atherosclerotic Lesions
2008
Nanoparticle contrast agents for MRI may aid in identifying atherosclerotic lesions that give rise to ischemic events by means of penetration and retention in the plaque. These imaging agents may provide valuable information regarding plaque characteristics which can help determine the risk of plaque rupture. By increasing molecular flexibility or adding a means of specifically targeting ligands via antibody or peptide, nanoparticles can enhance certain regions of the atherosclerotic plaque. The development of single contrast agents detectable with multiple imaging modalities may further improve our ability to detect and characterize atherosclerosis in clinical and preclinical applications.…
Macrophages as an Emerging Source of Wnt Ligands: Relevance in Mucosal Integrity
2019
The Wnt signaling pathway is a conserved pathway involved in important cellular processes such as the control of embryonic development, cellular polarity, cellular migration, and cell proliferation. In addition to playing a central role during embryogenesis, this pathway is also an essential part of adult homeostasis. Indeed, it controls the proliferation of epithelial cells in different organs such as intestine, lung, and kidney, and guarantees the maintenance of the mucosa in physiological conditions. The origin of this molecular pathway is the binding between Wnt ligands (belonging to a family of 19 different homologous secreted glycoproteins) and their specific membrane receptors, from …
Binding of RNA Aptamers to Membrane Lipid Rafts: Implications for Exosomal miRNAs Transfer from Cancer to Immune Cells
2020
Intraluminal vesicles (ILVs) are released into the extracellular space as exosomes after the fusion of multivesicular bodies (MVBs) with the plasma membrane. miRNAs are delivered to the raft-like region of MVB by RNA-binding proteins (RBPs). RNA loading into exosomes can be either through direct interaction between RNA and the raft-like region of the MVB membrane, or through interaction between an RBP&ndash
Selection of Membrane RNA Aptamers to Amyloid Beta Peptide: Implications for Exosome-Based Antioxidant Strategies
2019
The distribution of amyloid beta peptide 42 (Aβ42) between model exosomal membranes and a buffer solution was measured. The model membranes contained liquid-ordered regions or phosphatidylserine. Results demonstrated that up to ca. 20% of amyloid peptide, generated in the plasma (or intracellular) membrane as a result of proteolytic cleavage of amyloid precursor proteins by β- and γ-secretases, can stay within the membrane milieu. The selection of RNA aptamers that bind to Aβ42 incorporated into phosphatidylserine-containing liposomal membranes was performed using the selection-amplification (SELEX) method. After eight selection cycles, the pool of RNA aptamers was isol…
Rare‐earth cyclobutadienyl sandwich complexes: Synthesis, structure and dynamic magnetic properties
2018
The potassium cyclobutadienyl [K2{η4‐C4(SiMe3)4}] (1) reacts with MCl3(THF)3.5 (M=Y, Dy) to give the first rare‐earth cyclobutadienyl complexes, that is, the complex anions [M{η4‐C4(SiMe3)4}{η4‐C4(SiMe3)3‐κ‐(CH2SiMe2}]2−, (2M), as their dipotassium salts. The tuck‐in alkyl ligand in 2M is thought to form through deprotonation of the “squarocene” complexes [M{η4‐C4(SiMe3)4}2]− by 1. Complex 2Dy is a single‐molecule magnet, but with prominent quantum tunneling. An anisotropy barrier of 323(22) cm−1 was determined for 2Dy in an applied field of 1 kOe, and magnetic hysteresis loops were observed up to 7 K. nonPeerReviewed