Progress reaction profiles are affected by both catalyst activation and deactivation processes occurring alongside the main reaction. These processes complicate the kinetic analysis of reactions, often directing researchers toward incorrect conclusions. We report the application of two kinetic treatments, based on variable time normalization analysis, to reactions involving catalyst activation and deactivation processes. The first kinetic treatment allows the removal of induction periods or the effect of rate perturbations associated with catalyst deactivation from kinetic profiles when the quantity of active catalyst can be measured. The second treatment allows the estimation of the activation or deactivation profile of the catalyst when the order of the reactants for the main reaction is known. Both treatments facilitate kinetic analysis of reactions suffering catalyst activation or deactivation processes.
An efficient approach to (Rp) planar-chiral tri- and tetracyclic ortho-condensed aromatic ferrocenes was developed through the enantioselective cationic Au(i)-catalyzed cycloisomerization, in the presence of bidentate phosphine ligand (R)-DTBM-Segphos, from readily available ortho-alkynylaryl ferrocenes under very mild conditions (11 examples, up to 92% yield and 93% ee).
An enantiopure helical ferrocene (R p )-5 with five ortho-condensed aromatic rings was synthesized using a PtCl 2catalyzed cycloisomerization of planar-chiral 2-ethynyl-1-(4-phenanthrenyl)ferrocene (R p )-6f, prepared in 3 steps from known enantiopure sulfinyl ferrocenyl boronic acid (S S ,S p )-7, as the source of planar chirality. This pentacyclic helical ferrocene showed a very high optical rotation value and strong circular dichroism (CD) signals.
Prof. A. Vidal-Ferran ICREA Passeig LluïsC ompanys,2 3, 08010 Barcelona (Spain) Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.
Active catalysts derived from cobalt and the Xantphos ligand were synthesised, characterised and tested in the hydroformylation of pure linear alkenes or their mixtures. The preformed complex [Co2(CO)6(Xantphos)] showed similar...
Ring-opening
polymerization and teroligomerization processes that
involve two different epoxides and carbon dioxide are significantly
more efficiently executed in a supercritical CO2 medium.
Here, we demonstrate that this generally considered green medium is
advantageous for the catalytic formation of both conventional and
biobased co- and teroligomers avoiding the occurrence of diffusion-limited
catalysis while maximizing the polymer quality, yield, and carbonate
content.
Over several years, our research team has contributed to ligand design for metal-catalyzed stereoselective transformations. This has been achieved with the synthesis and application to organic transformations of interest of an array of structurally diverse P-containing ligands. These range from highly modular enantiopure phosphine–phosphite ligands to supramolecularly regulated enantioselective phosphorus-based catalysts. Our research in supramolecular interactions has also led to the discovery of an unprecedented halogen-bonded rhodium-catalyst.
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