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Start Over Descriptor "Tolman electronic parameter" Publisher beilstein-institut
3 results on '"Tolman electronic parameter"'

1. Backbone tuning in indenylidene–ruthenium complexes bearing an unsaturated N-heterocyclic carbene

Author

César A. Urbina-Blanco, Xavier Bantreil, Hervé Clavier, Alexandra M. Z. Slawin, and Steven P. Nolan

Subjects
N-heterocyclic carbene, olefin metathesis, percent buried volume, ruthenium–indenylidene, Tolman electronic parameter, Science, Organic chemistry, QD241-441
Abstract

The steric and electronic influence of backbone substitution in IMes-based (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) N-heterocyclic carbenes (NHC) was probed by synthesizing the [RhCl(CO)2(NHC)] series of complexes to quantify experimentally the Tolman electronic parameter (electronic) and the percent buried volume (%Vbur, steric) parameters. The corresponding ruthenium–indenylidene complexes were also synthesized and tested in benchmark metathesis transformations to establish possible correlations between reactivity and NHC electronic and steric parameters.

Published
2010
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2. Rhodium, iridium and nickel complexes with a 1,3,5-triphenylbenzene tris-MIC ligand. Study of the electronic properties and catalytic activities

Author

Eduardo Peris, Beatriz Royo, Gregorio Guisado-Barrios, and Carmen Mejuto

Subjects
Tolman electronic parameter, Stereochemistry, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Full Research Paper, Rhodium, Catalysis, lcsh:QD241-441, chemistry.chemical_compound, nickel, lcsh:Organic chemistry, Polymer chemistry, Iridium, lcsh:Science, 010405 organic chemistry, Ligand, Organic Chemistry, Mesoionic, iridium, 0104 chemical sciences, 3. Good health, Nickel, Chemistry, arylation of unsaturated ketones, mesoionic carbenes, chemistry, rhodium, lcsh:Q, Carbene
Abstract

The coordination versatility of a 1,3,5-triphenylbenzene-tris-mesoionic carbene ligand is illustrated by the preparation of complexes with three different metals: rhodium, iridium and nickel. The rhodium and iridium complexes contained the [MCl(COD)] fragments, while the nickel compound contained [NiCpCl]. The preparation of the tris-MIC (MIC = mesoionic carbene) complex with three [IrCl(CO)2] fragments, allowed the estimation of the Tolman electronic parameter (TEP) for the ligand, which was compared with the TEP value for a related 1,3,5-triphenylbenzene-tris-NHC ligand. The electronic properties of the tris-MIC ligand were studied by cyclic voltammetry measurements. In all cases, the tris-MIC ligand showed a stronger electron-donating character than the corresponding NHC-based ligands. The catalytic activity of the tri-rhodium complex was tested in the addition reaction of arylboronic acids to α,β-unsaturated ketones. We gratefully acknowledge financial support from MINECO of Spain (CTQ2014-51999-P), UJI (P11B2014-02), Generalitat Valenciana (GV/2015/097) and FCT-Fundação para a Ciência e a Tecnologia (UID/Multi/04551/2013 and PTDC/QEQ- QIN/ 0565/2012). C. M. is thankful to the FPI program for a fellowship, B. R. thanks FCT for IF/00346/2013 and G. G.-B. thanks the MINECO for a postdoctoral grant (FPDI-2013-16525). The authors are grateful to the Serveis Centrals d’Instrumentació Científica (SCIC) of the Universitat Jaume I for providing with spectroscopic and X-ray facilities, and to FCT (RECI/BBBBQB/ 0230/2012).

Published
2015

3. Backbone tuning in indenylidene-ruthenium complexes bearing an unsaturated N-heterocyclic carbene.

Author

Urbina-Blanco CA, Bantreil X, Clavier H, Slawin AM, and Nolan SP

Abstract

The steric and electronic influence of backbone substitution in IMes-based (IMes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) N-heterocyclic carbenes (NHC) was probed by synthesizing the [RhCl(CO)₂(NHC)] series of complexes to quantify experimentally the Tolman electronic parameter (electronic) and the percent buried volume (%V(bur), steric) parameters. The corresponding ruthenium-indenylidene complexes were also synthesized and tested in benchmark metathesis transformations to establish possible correlations between reactivity and NHC electronic and steric parameters.

Published
2010
Full Text
View/download PDF

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