Rhodium(I) and Silver(I) Complexes of 4, 5‐Dicyano‐1, 3‐dimesityl‐ and 4, 5‐Dicyano‐1, 3‐dineopentylimidazol‐2‐ylidene

Baier, Heiko; Kelling, Alexandra; Jackstell, Ralf; Holdt, Hans‐Jürgen

doi:10.1002/zaac.201300250

Cited by 8 publications

(14 citation statements)

References 40 publications

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“…The mean C carbene ÀM distances of 206.0(3) pm (M = Rh) and 206(1)pm( M = Ir) are reasonably comparable to those found for otherN HC complexes of [M(cod)Cl]. [15][16][17] One striking feature is furthermore the bending of the structures ( Figure 3b), which is much more pronounced for 2h than 2a (absolutev alue of the averaged eviation from the plane defined by the central arene ring is 105.6 pm for 2a and 175.4 pm for 2h,r espectively).…”

Section: Synthetic Aspectssupporting

confidence: 71%

“…Nevertheless, both the absolutev alues of the 13 C(carbene) chemical shifts of 201.0 and 197.8 ppm for 2a and 2h,r espectively,a nd the 1 J( 103 Rh, 13 C) coupling constant of 49.1 Hz comparer easonably well with literature values. [15][16][17] The experimental UV/Vis spectra of 2a and 2h in CH 2 Cl 2 solution are similar ( Figure 4). Dominant transitions are observed at~33 000 cm À1 (e = 107 and 80 10 3 Lmol À1 cm À1 for 2a and 2h,r espectively)a nd~27 000 cm À1 (e = 56 and 80 10 3 Lmol À1 cm À1 for 2a and 2h,r espectively).…”

Section: Synthetic Aspectsmentioning

confidence: 73%

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Differential Many‐Body Cooperativity in Electronic Spectra of Oligonuclear Transition‐Metal Complexes

et al. 2015

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In computational chemistry, non-additive and cooperative effects can be defined in terms of a (differential) many-body expansion of the energy or any other physical property of the molecular system of interest. One-body terms describe energies or properties of the subsystems, two-body terms describe non-additive but pairwise contributions and three-body as well as higher-order terms can be interpreted as a measure for cooperativity. In the present article, this concept is applied to the analysis of ultraviolet/visible (UV/Vis) spectra of homotrinuclear transition-metal complexes by means of a many-body expansion of the change in the spectrum induced by replacing each of the three transition-metal ions by another transition-metal ion to yield a different homotrinuclear transition-metal complex. Computed spectra for the triangulo-complexes [M3 {Si(mt(Me) )3}2] (M=Pd/Pt, mt(Me) =methimazole) and tritopic triphenylene-based N-heterocyclic carbene Rh/Ir complexes illustrate the concept, showing large and small differential three-body cooperativity, respectively.

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Section: Synthetic Aspectssupporting

confidence: 71%

Section: Synthetic Aspectsmentioning

confidence: 73%

Differential Many‐Body Cooperativity in Electronic Spectra of Oligonuclear Transition‐Metal Complexes

et al. 2015

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“…IDNP (E σ : -8.89 eV; E π : -2.57 eV) [14] is the weakest σ-donor, but the strongest π-acceptor of the five NHCs. These data correlate with the TEP ranking of IPr (2052 cm -1 ), [15] IMeDNP (2058 cm -1 ), [14] (CN) 2 IMes (2060 cm -1 ) [11] and IDNP (2063 cm -1 ). [14] Based on these results, we expect (CN) 2 -IBzPic to show a similar π-accepting behaviour to (CN) 2 -IMes.…”

Section: Dft Calculationssupporting

confidence: 66%

“…[17] Compounds 1, [11] 4, [12] [PdCl 2 (PPh 3 For all manipulations, solvents were dried according to literature procedures.…”

Section: Methodsmentioning

confidence: 99%

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Efficient Palladium(II) Precatalysts Bearing 4,5‐Dicyanoimidazol‐2‐ylidene for the Mizoroki–Heck Reaction

et al. 2014

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The new N-heterocyclic carbene (NHC) complex [PdCl 2 {(CN) 2 IMes}(PPh 3 )] (2) ({(CN) 2 IMes}: 4,5-dicyano-1,3dimesitylimidazol-2-ylidene) and the NHC palladacycle [PdCl(dmba){(CN) 2 IMes}] (3) (dmba: N,N-dimethylbenzylamine) have been synthesized by thermolysis of 4,5-dicyano-1,3-dimesityl-2-(pentafluorophenyl)imidazoline (1) in the presence of suitable palladium(II) precursors. The acyclic complex 2 was formed by ligand exchange using the mononuclear precursor [PdCl 2 (PPh 3 ) 2 ] and the palladacycle 3 was formed by cleavage of the dinuclear chloro-bridged precursor [Pd(μ-Cl)(dmba)] 2 . The new NHC precursor 1-benzyl-4,5dicyano-2-(pentafluorophenyl)-3-picolylimidazoline (5) was formed by condensation of pentafluorobenzaldehyde with Nbenzyl-NЈ-picolyldiaminomaleonitrile (4). The NHC palladacycle [PdCl 2 {(CN) 2 IBzPic}] (6) ({(CN) 2 IBzPic}: 1-benzyl-4,5dicyano-3-picolylimidazol-2-ylidene) was prepared by in situ [a] 2952 thermolysis of 5 in the presence of [PdCl 2 (PhCN) 2 ]. The three palladium(II) complexes were characterized by NMR and IR spectroscopy, mass spectrometry and elemental analysis. In addition, the molecular structures of 2 and 3 were determined by X-ray diffraction. The π-acidity of (CN) 2 IBzPic was compared with (CN) 2 IMes and perviously reported π-acidic imidazol-2-ylidenes by NBO analysis. The Mizoroki-Heck (MH) reactions of various aryl halides with n-butyl acrylate were performed in the presence of complexes 2, 3 and 6. The new precatalysts showed high activity in the MH reactions giving good-to-excellent product yields with 0.1 mol-% precatalyst. The nature of the catalytically active species of 2, 3 and 6 was investigated by poisoning experiments with mercury and transmission electron microscopy. It was found that palladium nanoparticles formed from the precatalysts were involved in the catalytic process.Scheme 2. Preparation of NHC palladium(II) complexes 2 and 3.

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PEPPSI‐Effect on Suzuki–Miyaura Reactions Using 4,5‐Dicyano‐1,3‐dimesitylimidazol‐2‐ylidene‐Palladium Complexes: A Comparison between trans‐Ligands

2015

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The PEPPSI (Pyridine Enhanced Precatalyst Preparation, Stabilization and Initiation) complexes 12-15 with the structure [PdCl 2 {(CN) 2 IMes}(3-R-py)] (12: R = H; 13: R = Cl; 14: R = Br; 15: R = CN) bearing the maleonitrile-based N-heterocyclic carbene (NHC) (CN) 2 IMes ({(CN) 2 IMes}: 4,5-dicyano-1,3-dimesitylimidazol-2-ylidene) were prepared. Solid state structures of 14 and 15 were obtained. Complexes 14 and 15 adopt a slightly distorted square-planar coordination geometry in the solid state with the substituted pyridine ligand trans to the NHC. Catalytic activities of precatalysts 12-15 were studied and subsequently compared to complexes

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Rhodium(I) and Silver(I) Complexes of 4, 5‐Dicyano‐1, 3‐dimesityl‐ and 4, 5‐Dicyano‐1, 3‐dineopentylimidazol‐2‐ylidene

Cited by 8 publications

References 40 publications

Differential Many‐Body Cooperativity in Electronic Spectra of Oligonuclear Transition‐Metal Complexes

Differential Many‐Body Cooperativity in Electronic Spectra of Oligonuclear Transition‐Metal Complexes

Efficient Palladium(II) Precatalysts Bearing 4,5‐Dicyanoimidazol‐2‐ylidene for the Mizoroki–Heck Reaction

PEPPSI‐Effect on Suzuki–Miyaura Reactions Using 4,5‐Dicyano‐1,3‐dimesitylimidazol‐2‐ylidene‐Palladium Complexes: A Comparison between trans‐Ligands

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