Search results for " LIGANDS"
showing 10 items of 196 documents
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.
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…
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…
Nonheme Fe(IV) Oxo Complexes of Two New Pentadentate Ligands and Their Hydrogen-Atom and Oxygen-Atom Transfer Reactions.
2015
Two new pentadentate {N5} donor ligands based on the N4Py (N4Py = N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl)methylamine) framework have been synthesized, viz. [N-(1-methyl-2-benzimidazolyl)methyl-N-(2-pyridyl)methyl-N-(bis-2-pyridyl methyl)amine] (L1) and [N-bis(1-methyl-2-benzimidazolyl)methyl-N-(bis-2-pyridylmethyl)amine] (L2), where one or two pyridyl arms of N4Py have been replaced by corresponding (N-methyl)benzimidazolyl-containing arms. The complexes [FeII(CH3CN)(L)]2+ (L = L1 (1); L2 (2)) were synthesized, and reaction of these ferrous complexes with iodosylbenzene led to the formation of the ferryl complexes [FeIV(O)(L)]2+ (L = L1 (3); L2 (4)), which were characterized by UV–vis spe…
Triazolopyridines 22.1 Description of new 7,9-di(2-pyridyl)[1,2,3]triazolo[5',1':6,1]pyrido[3,2-d]pyrimidines
2002
The new heteroaromatic compounds, 7,9-di(2-pyridyl)[1,2,3]triazolo[5',1':6,1]pyrido[3,2-d] pyrimidines 11a-c, were synthesized in two steps from readily available triazolopyridines 1a-c. Regioselective lithiation of 1a-c followed by treatment with 2-cyanopyridine gave a mixture of compounds 5a-c, and 11a-c in moderate to low yields, together with gums. Similar reactions with the triazolopyridine 1d gave as the only identified compound the triazolopyridine derivative 5d. Abarca Gonzalez, Belen, Belen.Abarca@uv.es ; Ballesteros Campos, Rafael, Rafael.Ballesteros@uv.es ; Chadlaoui, Mimoun, michad@alumni.uv.es
Toxicity of ligand-dependent Cre recombinases and generation of a conditional Cre deleter mouse allowing mosaic recombination in peripheral tissues.
2007
Ligand-activated Cre recombinases are widely used for studying gene function in vitro and in conditional mouse models. To compare ligand-dependent Cre recombinases, different Cre estrogen receptor fusions were introduced into the ROSA26 locus of embryonic stem (ES) cells and assayed for genotoxicity and recombination efficiency. Of the tested recombinases, the CreERT2 variant showed no toxicity and was highly responsive to ligand induction. To constitutively express CreERT2 in mice and also to clarify whether the CreERT2 system displays background activity, we generated a knock-in mouse line harboring the CreERT2 coding region under the control of the ROSA26 locus. Analysis of this ROSA26-…
Expression of spindle assembly checkpoint proteins BubR1 and Mad2 expression as potential biomarkers of malignant transformation of oral leukoplakia:…
2021
Background The Spindle Assembly Checkpoint (SAC) is a surveillance mechanism essential to ensure the accuracy of chromosome segregation during mitosis. Our aim was to evaluate the expression of SAC proteins in oral carcinogenesis, and to assess their potential in predicting malignant transformation of oral leukoplakia. Material and Methods We analysed the immunoexpression of BubR1, Mad2, Bub3, and Spindly proteins in 64 oral biopsies from 52 oral leukoplakias and 12 normal tissues. Univariate and multivariate analysis were performed to evaluate predictive factors for malignant transformation (MT). Results We observed that BubR1 and Mad2 were more highly expressed in high dysplasia grade les…
Cross-species transcriptomic analysis elucidates constitutive aryl hydrocarbon receptor activity
2014
Background Research on the aryl hydrocarbon receptor (AHR) has largely focused on variations in toxic outcomes resulting from its activation by halogenated aromatic hydrocarbons. But the AHR also plays key roles in regulating pathways critical for development, and after decades of research the mechanisms underlying physiological regulation by the AHR remain poorly characterized. Previous studies identified several core genes that respond to xenobiotic AHR ligands across a broad range of species and tissues. However, only limited inferences have been made regarding its role in regulating constitutive gene activity, i.e. in the absence of exogenous ligands. To address this, we profiled transc…
Beta-carbolines as benzodiazepine receptor ligands II: Synthesis and benzodiazepine receptor affinity of beta-carboline-3-carboxylic acid amides.
1985
Numerous beta-carboline-3-carboxamides were synthesized by amidation of beta-carboline-3-carboxylic acid, with various amino acids and amino acid esters serving as amine components, and tested in respect to their affinity for the benzodiazepine receptor in mouse brain membranes. The title compounds have affinities in the low micromolar range. The results are discussed with respect to their relevance for a possible beta-carboline structure containing the endogenous ligand of the benzodiazepine receptor.