Search results for "ligands"
showing 10 items of 721 documents
Enantioselective addition of nitromethane to α-keto esters catalyzed by copper(ii)–iminopyridine complexes
2008
The copper complex of a chiral iminopyridine easily prepared from (R)-(-)-fenchone and picolylamine catalyzes the enantioselective Henry (nitroaldol) reaction between nitromethane and alpha-keto esters. Good yields and modest to good enantioselectivities are obtained for a wide range of alpha-keto esters, bearing aromatic, alkyl or alkenyl groups attached to the ketone carbonyl group.
Liver X Receptor ligand cytotoxicity in colon cancer cells and not in normal colon epithelial cells depends on LXRβ subcellular localization
2015
Increasing evidence indicates that Liver X Receptors (LXRs) have some anticancer properties. We recently demonstrated that LXR ligands induce colon cancer cell pyroptosis through an LXRβ-dependent pathway. In the present study, we showed that human colon cancer cell lines presented differential cytoplasmic localizations of LXRβ. This localization correlated with caspase-1 activation and cell death induction under treatment with LXR ligand. The association of LXRβ with the truncated form of RXRα (t-RXRα) was responsible for the sequestration of LXRβ in the cytoplasm in colon cancer cells. Moreover t-RXRα was not expressed in normal colon epithelial cells. These cells presented a predominantl…
The construction of open GdIII metal–organic frameworks based on methanetriacetic acid: New objects with an old ligand
2010
11 páginas, 11 figuras, 2 esquemas.-- et al.
Lanthanide molecular oxohydroxides: Synthesis and characterisation of [Y4(μ4-O)(μ-OEt)2(μ,η2-AAA)2(η2-AAA)3]2(μ3-OH)4(μ3-OEt)2 (HAAA = allylacetatoac…
2007
International audience; The reaction between Y5O(OPri)13 and allylacetatoacetate or 2-(methacryloyloxy)ethyl acetatoacetate in 1:5 stoichiometry afforded octanuclear oxohydroxo species. Structural characterization was achieved for the allylacetatoacetate derivative homo and copolymerisation reactions with styrene were evaluated for doping of polystyrene. Hydoxo species, Y4(OH)2(AAA)10, where also obtained by reacting Y[N(SiMe3)]3 and HAAA.
Divergent Adsorption-Dependent Luminescence of Amino-Functionalized Lanthanide Metal-Organic Frameworks for Highly Sensitive NO2 Sensors
2020
International audience; A novel gas sensing mechanism exploiting lanthanide luminescence modulation upon NO2 adsorption is demonstrated here. Two isostructural lanthanide-based metal–organic frameworks (MOFs) are used, including an amino group as the sensitive recognition center for NO2 molecules. The transfer of energy from the organic ligands to Ln is strongly dependent on the presence of NO2, resulting in an unprecedented photoluminescent sensing scheme. Thereby, NO2 exposition triggers either a reversible enhancement or a decrease in the luminescence intensity, depending on the lanthanide ion (Eu or Tb). Our experimental studies combined with density functional theory and complete activ…
Extended dipyrrin ligands : candidates for optical metal ion detection under competitive conditions
2017
Acylhydrazone based extended dipyrrins L1-H and L2-H are introduced as complexometric ppb sensitive metal ion detectors. The binding of lanthanide, transition as well as post-transition metal ions is followed by UV-Vis measurements. The carbohydrate based ligand L2 is water soluble and thus can act as a metal ion sensor in this medium.
A Dysprosium Metallocene Single-Molecule Magnet Functioning at the Axial Limit
2017
Abstraction of a chloride ligand from the dysprosium metallocene [(Cpttt)2DyCl] (1Dy Cpttt=1,2,4‐tri(tert‐butyl)cyclopentadienide) by the triethylsilylium cation produces the first base‐free rare‐earth metallocenium cation [(Cpttt)2Dy]+ (2Dy) as a salt of the non‐coordinating [B(C6F5)4]− anion. Magnetic measurements reveal that [2Dy][B(C6F5)4] is an SMM with a record anisotropy barrier up to 1277 cm−1 (1837 K) in zero field and a record magnetic blocking temperature of 60 K, including hysteresis with coercivity. The exceptional magnetic axiality of 2Dy is further highlighted by computational studies, which reveal this system to be the first lanthanide SMM in which all low‐lying Kramers doub…
Effects of PPARγ agonists on the expression of leptin and vascular endothelial growth factor in breast cancer cells.
2013
The obesity hormone leptin has been implicated in breast cancer development. Breast cancer cells express the leptin receptor and are able to synthesize leptin in response to obesity-related stimuli. Furthermore, leptin is a positive regulator of vascular endothelial growth factor (VEGF) and high levels of both proteins are associated with worse prognosis in breast cancer patients. Peroxisome proliferator-activated receptor γ (PPARγ) ligands are therapeutic agents used in patient with Type 2 diabetes and obesity which have recently been studied for their potential anti-tumor effect. Here, we studied if these compounds, ciglitazone and GW1929, can affect the expression of leptin and VEGF in b…
Thermodynamics of the Interaction between the Spike Protein of Severe Acute Respiratory Syndrome Coronavirus-2 and the Receptor of Human Angiotensin-…
2020
Since the end of 2019, the coronavirus SARS-CoV-2 has caused more than 1000000 deaths all over the world and still lacks a medical treatment despite the attention of the whole scientific community. Human angiotensin-converting enzyme 2 (ACE2) was recently recognized as the transmembrane protein that serves as the point of entry of SARS-CoV-2 into cells, thus constituting the first biomolecular event leading to COVID-19 disease. Here, by means of a state-of-the-art computational approach, we propose a rational evaluation of the molecular mechanisms behind the formation of the protein complex. Moreover, the free energy of binding between ACE2 and the active receptor binding domain of the SARS…
Guidelines to design new spin crossover materials
2010
International audience; This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been r…