Heterogeneous Ligands
Mostrando 1-12 de 25 artigos, teses e dissertações.
-
1. Gold Catalysis for Selective Hydrogenation of Aldehydes and Valorization of Bio-Based Chemical Building Blocks
Gold catalysts are best known for their selectivity in oxidation reactions, however, there is a promising future for gold in selective hydrogenations. Herein, the hydrogenation of several aldehydes and important bio-based chemical building blocks, namely 5-hydroxymethylfurfural (5-HMF), furfural and vanillin, was performed throughout the combination of Au na
J. Braz. Chem. Soc.. Publicado em: 21/10/2019
-
2. Estudo de interação de Hg(II) com ligantes heterogêneos de ocorrência natural usando voltametria de redissolução anódica automatizada em sistema de análise por injeção sequencial / Interaction of Hg (II) with heterogeneous naturally occurring ligands studied by anodic stripping voltammetry automated by sequential injection analysis
Dentre as espécies químicas metálicas responsáveis pela contaminação do meio aquático, mercúrio e outros compostos mercuriais têm recebido atenção especial devido a sua alta toxicidade. Os ligantes de ocorrência natural formam complexos com íons de Hg2+, influenciando a sua biodisponibilidade. Em meio a esses ligantes, dá-se destaque aos ligant
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/05/2012
-
3. Oligomerização de olefinas leves catalisada por complexos contendo ligantes B-diimina heterogeneizados em sílica
This work describes ¿-diimine ligands synthesis and the corresponding nickel complexes, homogeneous and heterogeneized, its catalytic application in ethylene oligomerization. Initially held the ¿-diimine ligands synthesis with different substituents in the aromatic ring. These ligands were characterized by CHN elemental analysis, IR, UV-Vis and 1H NRM. Fro
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2011
-
4. Sintese e heterogeneização de complexos de paladio : aplicação em reações de acoplamento C-C / Synthesis and heterogeneization of palladium complexes : application in C-C cross-coupling reactions
In this work, palladium complexes, in which phosphored ligands are anchored to cyclophosphazenes were synthesized. These complexes, in solution or immobilized in inorganic matrices, were tested in the Suzuki cross-coupling reaction (between phenylboronic acid and bromobenzene, for example), the Stille cross-coupling reaction (between tributylvinyltin and
Publicado em: 2007
-
5. Preparation and reative studies of catalytic systems based on zirconocenes, face to homo-and co-polimerization reation of etene / Preparação e estudo de reatividade de sistemas catalíticos, a base de zirconocenos, frente à reação de homo- e copolimerização de eteno
Catalytic systems based on zirconoces which are able to polymerize ethene have been studied. Structural modifications on the basic catalytic precursor, diphenylmethylidene(η5- cyclopentadienyl)(η5-9-fluorenyl) zirconium dichloride (5a) have been carried out. The catalytic precursors 5a and bis(para-fluorophenyl)methylidene(η5-cyclopentadienyl)
Publicado em: 2007
-
6. Novel catalyst systems based on Ni(II), Ti(IV), and Cr(III) complexes for oligo-and polymerization of ethylene
The complex of Brookhart Ni(α-diimine)Cl2 (1) (α-diimine = 1,4-bis(2,6- diisopropylphenyl)-acenaphthenediimine) has been characterized after impregnation on silica (S1) and MAO-modified silicas (4.0, 8.0 and 23.0 wts.% Al/SiO2 called S2, S3 and S4, respectively). The treatment of these heterogeneous systems with MAO produces some active catalysts for the p
Publicado em: 2007
-
7. Sintese , caracterizaÃÃo e eletroatividade de sams formadas com compostos catiÃnicos de tetraaminas de rutÃnio / Synthesis, characterization and eletroatividade of sams formed with composites catiÃnicos of tetraaminas of rutÃnio
Trans-[Ru(CNpy)(NH3)4(L)]2+ type complexes, where CNpy (4- Cyanopyridine), L= 1,4-dt (1,4-dithiane), pyS (4-mercaptopyridine), and Tio (thionicotinamide), were synthesized and characterized by HPLC, microanalysis, eletrochemistry and vibrational and eletronic spectroscopies. The eletrochemical and eletronic absorption results are indicative of a π back-
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 08/09/2006
-
8. CCR5 genotype and plasma ß-chemokine concentration of Brazilian HIV-infected individuals
The 32-bp deletion in the HIV-1 co-receptor CCR5 confers a high degree of resistance to HIV-1 infection in homozygous individuals for the deleted allele and partial protection against HIV-1 during disease progression in heterozygotes. Natural ligands for CCR5, MIP-1alpha, MIP-1ß and RANTES, have been shown to inhibit HIV replication in CD4+ T cells. In the
Brazilian Journal of Medical and Biological Research. Publicado em: 2002-11
-
9. Characterization of the mRNA ligands bound by the RNA binding protein hnRNP A2 utilizing a novel in vivo technique
Post-transcriptional regulation is an important mechanism in cellular response to stimuli, allowing for the rapid and discrete expression of relevant proteins. Genes regulated by this mechanism have specific cis-acting elements, frequently in their 3′ untranslated regions (UTRs), that have been shown to serve as recognition sites for trans-acting RNA-bindi
Oxford University Press.
-
10. Sequence specificity of actinomycin D and Netropsin binding to pBR322 DNA analyzed by protection from DNase I.
A direct approach to determining the sequence specificities of equilibrium binding drugs by using the DNase protection technique is described. The method utilizes singly end-labeled restriction fragments and partial digestion of the drug fragment complex with DNase I. Microdensitometry of autoradiograms produced after electrophoretic separation of digestion
-
11. Retinoic acid receptor α1 variants, RARα1ΔB and RARα1ΔBC, define a new class of nuclear receptor isoforms
Retinoic acid (RA) binds and activates retinoid X receptor (RXR)/retinoic acid receptor (RAR) heterodimers, which regulate the transcription of genes that have retinoic acid response elements (RARE). The RAR isotypes (α, β and γ) are comprised of six regions designated A–F. Two isoforms of RARα, 1 and 2, have been identified in humans, which have diffe
Oxford University Press.
-
12. Single-molecule enzymology of RNA: Essential functional groups impact catalysis from a distance
The hairpin ribozyme is a minimalist paradigm for studying RNA folding and function. In this enzyme, two domains dock by induced fit to form a catalytic core that mediates a specific backbone cleavage reaction. Here, we have fully dissected its reversible reaction pathway, which comprises two structural transitions (docking/undocking) and a chemistry step (c
National Academy of Sciences.