A5016381039- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Research on Leishmaniasis Studies
- Trypanosoma species research and implications
- Synthesis and Biological Evaluation
- Supramolecular Chemistry and Complexes
- Synthetic Organic Chemistry Methods
- Study of Mite Species
- Catalytic Alkyne Reactions
- Synthesis and biological activity
- Porphyrin and Phthalocyanine Chemistry
- Asymmetric Hydrogenation and Catalysis
- Luminescence and Fluorescent Materials
- Catalytic C–H Functionalization Methods
- Organometallic Complex Synthesis and Catalysis
- Parasite Biology and Host Interactions
- Chemical Synthesis and Analysis
- Molecular Junctions and Nanostructures
- Bioactive Compounds and Antitumor Agents
- Animal Ecology and Behavior Studies
- Avian ecology and behavior
- Bird parasitology and diseases
- Crystallography and molecular interactions
- Parasites and Host Interactions
- Catalytic Cross-Coupling Reactions
Institut Pasteur de Montevideo
2014-2025
Universidad San Francisco de Quito
2022-2025
Corporation d’Aménagement et de Protection de la Sainte-Anne
2024
Amicrobe (United States)
2017
Ministerio de Salud Pública y Bienestar Social
2015
Universidad de la República de Uruguay
2009-2014
Institut Pasteur
2014
California Institute of Technology
2001-2013
University of California, Berkeley
2009-2011
Korea Advanced Institute of Science and Technology
2011
A new synthetic route to cyclic polymers has been developed in which the ends of growing polymer chains remain attached a metal complex throughout entire polymerization process. The approach eliminates need for linear polymeric precursors and high dilution, drawbacks traditional macrocyclization strategies, it effectively removes barrier producing large quantities pure material. Ultimately, strategy offers facile access unique macromolecular scaffold that may be used meet increasing demand...
In this paper we describe the phosphine-catalyzed [3 + 2], 3], [4 and 2 3] annulations of azomethine imines allenoates. These processes mark first use in nucleophilic phosphine catalysis, producing dinitrogen-fused heterocycles, including tetrahydropyrazolo-pyrazolones, -pyridazinones, -diazepinones, -diazocinones. Counting two different reaction modes cyclizations, there are five distinct pathways-the choice which depends on structure chemical properties allenoate. All reactions...
The first systematic mechanism study of C−F reductive elimination from a transition metal complex is described. bond formation three different Pd(IV) fluoride complexes was mechanistically evaluated. experimental data suggest that occurs cationic via dissociative mechanism. ancillary pyridyl-sulfonamide ligand plays crucial role for elimination, likely due to κ3 coordination mode, in which an oxygen atom the sulfonyl group coordinates Pd. can support and has appropriate geometry electronic...
Gold-ilocks and the 3 mol % catalyst: Bimetallic gold bromides allow room temperature aminoarylation of unactivated terminal olefins with aryl boronic acids using Selectfluor as an oxidant. A catalytic cycle involving gold(I)/gold(III) a bimolecular reductive elimination for key CC bond-forming step is proposed. dppm= bis(diphenylphosphanyl)methane. Detailed facts importance to specialist readers are published "Supporting Information". Such documents peer-reviewed, but not copy-edited or...
In 2009, we reported C−halogen reductive elimination reactions from dinuclear Pd(III) complexes and implicated intermediates in Pd(OAc)2-catalyzed C−H oxidation chemistry. Herein, report results of a thorough experimental theoretical investigation the mechanism such complexes, which establish role each metal during elimination. Our implicate complex core is intact suggest that redox synergy between two metals responsible for facile observed.
We present a detailed study of the mechanism for oxidative heteroarylation, based on DFT calculations and experimental observations. propose binuclear Au(II)-Au(II) complexes to be key intermediates in gold catalyzed heteroarylation. The reaction is thought proceed via redox cycle involving initial oxidation Au(I) by Selectfluor, followed heteroauration reductive elimination. While it tempting invoke transmetalation/reductive elimination similar that proposed other transition metal...
In this article the utility of phosphoramidite ligands in enantioselective Au(I) catalysis was explored development highly diastereo- and Au(I)-catalyzed cycloadditions allenenes. A synthesis 3,4-disubstituted pyrrolidines γ-lactams is described. This reaction proceeds through cyclization allenenes to form a carbocationic intermediate that trapped by an exogenous nucleophile, resulting diastereoselective construction three contiguous stereogenic centers. computational study (DFT) also...
The long and the short of it: A bistable molecular muscle, based on a doubly threaded Janus-type [2]rotaxane, is assembled using template-directed self-assembly process. Under influence changes in pH value, two identical matching components glide along one another through terminal crown ether moieties, bringing about expansion contraction molecule. Supporting information for this article available WWW under http://www.wiley-vch.de/contents/jc_2002/2008/z803036_s.pdf or from author. Please...
The synthesis of cyclic polybutadienes using ring-opening metathesis polymerization (ROMP) was accomplished. A Ru alkylidene catalyst, where a terminal ligand covalently linked to the alkylidene, used polymerize either 1,5-cyclooctadiene (COD) or 1,5,9-trans-cis-trans-cyclododecatriene (CDT). Trace amounts an acyclic impurity, 4-vinylcyclohexene, found in COD led samples which were contaminated with linear polymer. In contrast, CDT, free afforded pure These results provide convenient method...
Two intramolecularly hydrogen-bonded arylhydrazone (aryl = phenyl or naphthyl) molecular switches have been synthesized, and their full reversible switching between the E Z configurations demonstrated. These chemically controlled configurational rotary exist primarily as isomer at equilibrium can be switched to protonated configuration (Z-H(+)) by addition of trifluoroacetic acid. The protonation pyridine moiety in switch induces a rotation around hydrazone C=N double bond, leading...
The intermolecular hydroamination of allenes occurs readily with hydrazide nucleophiles, in the presence 3−12% Ph3PAuNTf2. Mechanistic studies have been conducted to establish resting state gold catalyst, kinetic order reaction, effect ligand electronics on overall rate, and reversibility last steps catalytic cycle. We found reaction be first allene zero nucleophile. Our suggest that rate-limiting transition for does not involve nucleophile active catalyst is monomeric gold(I). Computational...
Alkylgold(I) complexes were formed from the gold(I)-promoted intramolecular addition of various amine nucleophiles to alkenes. These experiments provide first direct experimental evidence for elementary step gold-promoted nucleophilic an alkene. Deuterium-labeling studies and X-ray crystal structures support a mechanism involving anti-addition nucleophile gold-activated alkene, which is verified by DFT analysis mechanism. Ligand indicate that rate aminoauration can be drastically increased...
Most organic radicals possess short lifetimes and quickly undergo dimerization or oxidation. Here, we report on the synthesis by radical templation of a class air- water-stable radicals, trapped within homo[2]catenane composed two rigid fixed cyclobis(paraquat-p-phenylene) rings. The highly energetic octacationic homo[2]catenane, which is capable accepting up to eight electrons, can be configured reversibly, both chemically electrochemically, between each one six experimentally accessible...
It is shown that [4 + 3] and 2] cycloaddition pathways are accessible in the Au(I) catalysis of allene−dienes. Seven-membered ring gold-stabilized carbenes, originating from process, unstable can rearrange via a 1,2-H or 1,2-alkyl shift to yield six- seven-membered products. Both steric electronic properties AuL+ catalyst affect structure intermediate carbene its subsequent reactivity.
The ability of the diradical dicationic cyclobis(paraquat-p-phenylene) (CBPQT2(•+)) ring to form inclusion complexes with 1,1′-dialkyl-4,4′-bipyridinium radical cationic (BIPY•+) guests has been investigated mechanistically and quantitatively. Two BIPY•+ cations, methyl viologen (MV•+) a dibutynyl derivative (V•+), were as for CBPQT2(•+) ring. Both trisradical complexes, namely, CBPQT2(•+)⊂MV•+ CBPQT2(•+)⊂V•+, respectively. structural details complex, which ascertained by single-crystal...
Two donor-acceptor [3]catenanes-composed of a tetracationic molecular square, cyclobis(paraquat-4,4'-biphenylene), as the π-electron deficient ring and either two tetrathiafulvalene (TTF) 1,5-dioxynaphthalene (DNP) containing macrocycles or TTF-butadiyne-containing rich components-have been investigated in order to study their ability form TTF radical dimers. It has proven that mechanically interlocked nature [3]catenanes facilitates formation dimers under redox control, allowing an...
The synthesis of a variety poly(norbornene)s (PNB)s bearing acetoxy, hydroxy, and vinyl end groups was accomplished. PNBs with an acetoxy group at one terminus the other were prepared using norbornene, ruthenium-based olefin metathesis catalyst (PCy3)2Cl2RuCHPh, allyl acetate as chain transfer agent (CTA). Employing more active catalyst, (1,3-dimesityl-4,5-dihydroimidazol-2-ylidene)(PCy3)Cl2RuCHPh, 1,4-diacetoxy-2-butene CTA afforded telechelic both ends polymer chains. Molecular weights...
Using density functional theory with the B3LYP and M06 functionals, we show conclusively that (H2IMes)(Cl)2Ru olefin metathesis mechanism is bottom-bound chlorides remaining trans throughout reaction, thus attempts to effect diastereo- enantioselectivity should focus on manipulations maintain trans-dichloro Ru geometry.
The structure of ruthenium-based olefin metathesis catalyst 3 and model π-complex 5 in solution the solid state are reported. N-tolyl ligands, due to their lower symmetry than traditional N-mesityl substituents, complicate this analysis, but ultimately provide explanation for enhanced reactivity relative standard 2. tilt ring provides additional space near ruthenium center, which is consistent with toward sterically demanding substrates. Due tilt, more accessible face bears two methyl...
Zweikernige Goldbromidkomplexe katalysieren die Aminoarylierung nichtaktivierter terminaler Olefine mit Arylboronsäuren und dem Oxidationsmittel Selectfluor bei Raumtemperatur. Ein Gold(I)-Gold(III)-Katalysezyklus einer bimolekularen reduktiven Eliminierung als Schlüsselschritt der C-C-Verknüpfung wird vorgeschlagen. dppm=Bis(diphenylphosphanyl)methan. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not...
The cis−trans chloride isomerization of a ruthenium olefin metathesis catalyst is studied using quantum mechanics (B3LYP DFT), including the Poisson−Boltzmann (PBF) continuum approximation. predicted geometries agree with experiment. energies in methylene chloride, lead to ΔG = −0.70 kcal/mol and cis:trans ratio 76:24, quite close experimental value −0.78 or c:t 78:22. In contrast, we predict that benzene 4:96 agreement observation only trans isomer. Our calculated relative activation...