The coordination of heterocumulenes and other unsaturated molecules to RhCl(P(C6H11)3)2

Gaal, H.L.M. van; Verlaan, J.P.J.

doi:10.1016/s0022-328x(00)98121-x

Cited by 53 publications

(6 citation statements)

References 32 publications

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“…We also considered the possibility that an iron(I)–carbodiimide complex is part of the mechanism, since carbodiimides are known to coordinate to low-valent metals. ,,− To investigate this hypothesis, a carbodiimide complex was independently prepared by adding 1,3-dicyclohexylcarbodiimide (DCC, CyNCNCy) to L t Bu FeNNFeL t Bu in hexane. Cooling the mixture at −45 °C afforded single crystals of the carbodiimide complex L t Bu Fe(η 2 -CyNCNCy) in 46% yield.…”

Section: Resultsmentioning

confidence: 99%

Mechanism of Catalytic Nitrene Transfer Using Iron(I)–Isocyanide Complexes

et al. 2013

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Low-spin iron(I) complexes supported by bulky β-diketiminate ligands catalyze the formation of unsymmetric carbodiimides (RNCNR′, R ≠ R′) from isocyanides and organoazides. In situ EPR studies indicate that the catalytic resting state in these reactions is the tris(isocyanide)iron(I) complex LFe(CNR)3, and kinetic experiments show that the reaction is inverse second-order in isocyanide concentration, suggesting that two isocyanide molecules dissociate prior to the rate-determining step. An unusual iron–carbodiimide complex can be isolated independently, and facile displacement of the coordinated carbodiimide by both isocyanide and N2 demonstrate that product release is not kinetically limiting during catalysis. These experimental data fit a coherent mechanism for the catalytic C–N coupling reaction, and the implications for catalytic nitrene transfer are discussed.

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Section: Resultsmentioning

confidence: 99%

Mechanism of Catalytic Nitrene Transfer Using Iron(I)–Isocyanide Complexes

et al. 2013

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“…Both the chemical shift and the observed coupling constants of the 13 C NMR carbene resonance in [6] match previously reported values obtained for Rh I complexs bearing classical NR,NR-functionalized NHCs and two additional phosphine ligands in cis and trans positions to the NHC ligand. 22 Given the high steric demand of the PCy 3 ligand, which, under standard conditions, yields with Rh I the 14-electron complex [RhCl(PCy 3 ) 2 ], 23 the formation of the two isomeric complexes [6] and [7] due to steric interactions of the phosphine ligands is not surprising. To avoid the formation of geometric isomers, we reacted the ligand precursor 3 with [RhCl(COE) 2 ] 2 in the presence of the sterically less demanding triphenyl phosphine (Scheme 3).…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…The 2 J PP coupling constant in [9] is of similar magnitude as the 2 J PP coupling constant in [7] ( 2 J P1P2 = 339 Hz), confirming the assignment of [7] as a trans-P,P complex. Both, the length of the spacer between the benzimidazole nitrogen atom and the phosphorus atom P1, leading to a larger P1ÀRhÀC carbene angle, and the bulkiness of the tricylohexyl phosphine, 23 contribute to the formation of the trans-P,P complex [9] compared to the cis-P, P complexes [6] and [8]. However, even with the P ∧ C chelate ligand featuring a methylene spacer obtained from 3, formation of trans-P,P complexes like [7] as a minor reaction was observed in the presence of a bulky monodentate phosphine like PCy 3 .…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…Given the high steric demand of the PCy 3 ligand, which, under standard conditions, yields with Rh I the 14-electron complex [RhCl(PCy 3 ) 2 ], the formation of the two isomeric complexes [ 6 ] and [ 7 ] due to steric interactions of the phosphine ligands is not surprising. To avoid the formation of geometric isomers, we reacted the ligand precursor 3 with [RhCl(COE) 2 ] 2 in the presence of the sterically less demanding triphenyl phosphine (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of Rhodium(I) Complexes Bearing Bidentate NH,NR-NHC/Phosphine Ligands

et al. 2011

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The N-alkyphosphine-substituted benzimidazoles 5 (R = methylenedicyclohexylphosphine), 7 (R = ethylene-di(tBu)phosphine), and 8 (R = ethylenedicyclohexylphosphine) have been prepared. The benzimidazoles react with [RhCl(COE)2]2 in the presence of tertiary phosphines under formal tautomerization of the benzimidazole and chelating coordination of the resulting bidentate NH,NR-NHC/phosphine ligand (P∧C) to give complexes [RhCl(P∧C)PR3] [6]–[9]. Depending on the steric demand of the PR3, the phosphines of the P∧C ligands, and on the spacer linking the benzimidazole ring nitrogen atom to the alkylphosphine, complexes with cis-P,P and trans-P,P geometry have been obtained and crystallographically characterized.

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“…13C NMR (C6D6,100.6 MHz): 161.0 (d, «/(PC) = 15.4 Hz, N=C=N), 145.5,129.4,127.0, and 120.9 (all s, CeH4), 92.7 (d, «/(PC) = 1.5 Hz, C6(CH3)6), 41.0 (d, «/(PC) = 1.5 Hz, NCH3), 20.9 (s, C6H4CH3), 17.1 (d,«/(PC) = 24. 6 Hz, PMe3), 10.5 (s, CB(CH3)B).…”

Section: Methodsmentioning

confidence: 99%