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

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

Beilstein J. Org. Chem. 2015, 11, 2584–2590, doi:10.3762/bjoc.11.278

• 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

• 5 showed the characteristic CO stretching bands at 2057 and 1972 cm−1 from which a Tolman electronic parameter (TEP) of 2042 cm−1 could be estimated by using the well-accepted correlations [54][55][56]. This obtained TEP value is slightly lower than the one shown by the tris-NHC analogue A, for

• average CO stretching frequency at 2018 cm−1 [32]. This frequency is 4 cm−1 higher than the average frequency observed for 5 (2014 cm−1), indicating a stronger electron-donating character of the tris-MIC ligand. In a similar way, the Tolman electronic parameter of 1-ethyl-3-phenylimidazolyidene (which may

Influence of bulky yet flexible N-heterocyclic carbene ligands in gold catalysis

• Alba Collado,
• Scott R. Patrick,
• Danila Gasperini,
• Sebastien Meiries and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 1809–1814, doi:10.3762/bjoc.11.196

• ITent ligands with different metals are currently ongoing. ‘ITent’ family of ligands, including IPr. First row: percentage buried volume (% Vbur) calculated in [Au(ITent)Cl] complexes using the SambVca software [42][43][44][45]. Second and third row: Tolman Electronic Parameter (TEP) calculated from IR

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

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

Beilstein J. Org. Chem. 2010, 6, 1120–1126, doi:10.3762/bjoc.6.128

• parameters. Keywords: N-heterocyclic carbene; olefin metathesis; percent buried volume; ruthenium–indenylidene; Tolman electronic parameter; Introduction The use of N-heterocyclic carbenes (NHC) as spectator ligands in ruthenium-mediated olefin metathesis represents one of the most important breakthroughs

• reaction conditions are required [13][23][24][25]. Herein, we present the synthesis and characterization of three new ruthenium–indenylidene catalysts and their performance in benchmark metathesis transformations. In order to quantify the Tolman electronic parameter associated with IMes-type (IMes = 1,3

• complexes [26][27][28][29][30][31][32]. This method was initially developed by Tolman [33], using the average infrared frequency of CO in [Ni(CO)3L] complexes. This electronic parameter has become known as the Tolman electronic parameter (TEP) and has been used to quantify the electron donor ability of