Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.
AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.
Electron-spin relaxation is one of the determining factors in the efficacy of MRI contrast agents. Of all the parameters involved in determining relaxivity it remains the least well understood, particularly as it relates to the structure of the complex. On ...
Reaction of N,N-dibenzyl-O-methylsulfonyl serine Me ester with a variety of heteronucleophiles (sodium azide, sodium phthalimide, amines, thiols) and carbanions (sodium malonate) gave, via an aziridinium intermediate, the corresponding beta -amino or alpha ...
The labile cobalt (II) complex [Co(TUF)2(Pic)2] with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (TUF) bidentate and 4-methylpyridine (Pic) monodentate ligands was studied by variable temp. (VT) 19F NMR from 184 to 312 K. In contrast to the solid state, ...
The molecular complex [Re(equivalent toC(t)Bu)(=(CHBu)-Bu-t)((CH2Bu)-Bu-t)2] (1) reacts with a silica partially dehydroxylated at 700 degreesC to give syn-2, [(equivalent toSiO)Re(equivalent toC(t)Bu)(=(CHBu)-Bu-t)((CH2Bu)-Bu-t)], as a single isomer accord ...
The potential role of Hox genes during vertebrate limb development was brought into focus by gene expression analyses in mice (P Dolle, JC Izpisua-Belmonte, H Falkenstein, A Renucci, D Duboule, Nature 1989, 342:767-772), at a time when limb growth and patt ...
Clusters of metal atoms at a fixed size can assume different structural arrangements, known as isomers, which may have nearly the same energy. Therefore at given experimental conditions distribution of these isomers can be present. While the size selection ...
A total asymmetric synthesis of the polyol subunit of the polyene macrolide antibiotic RK-397 was developed through the stereoselective functionalization of (1R,1’S,6S,6’R)-3,3’-methylenebis(cyclohept-3-ene-1,6-diol). The pathway generates a large variety ...
The conformational analysis of a series of configurational isomers of 2-(hydroxymethyl)azepan-3,4,5,6-tetrols 1-4 has been carried out. H-1 NMR spectroscopic data, especially vicinal J couplings and nuclear Overhauser enhancements (NOE), assisted by molecu ...
The reactivity of the cluster family [Ru-3(CO)(12-x)(L)x] (in which L = PMe3, PMe2Ph, PPh3 and PCy3, x = 1 - 3) towards hydrogen is described. When x=2, three isomers of [Ru-3(H)(mu-H)(CO)(9)(L)(2)] are formed, which differ in the arrangement of their equa ...
The Oshima-Nozaki (Et2AlI) condensation of isolevoglucosenone (4) with 2,6-anhydro-3,4,5,7-tetra-O-benzyl-D-glycero-D-gulo-heptose (5) gave an enone 6 that was converted with high stereoselectivity to 3-C-[(IR)-2,6-anhydro-D-glycero-D-gulo-heptitol-1-C-yl] ...