Carbene Complexes Made Easily: Decomposition of Reissert Compounds and Further Synthetic Approaches

Bittermann, Agnes; Baskakov, Denys; Herrmann, Wolfgang A.

doi:10.1021/om900354v

Cited by 34 publications

(16 citation statements)

References 61 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The characteristic downfield signals for the NC H N + protons of the imidazol(in)ium salts disappeared in the 1 H NMR spectra of complexes 4a , 4b , 5a , 5b , 6a , 6b . These complexes exhibit 13 C chemical shifts and coupling constants that are comparable to those of other reported NHC–rhodium(I) complexes . 13 C chemical shifts showed that C carbene is substantially deshielded.…”

Section: Resultssupporting

confidence: 79%

“…Practically almost all catalytic studies have been devoted to saturated imidazolin‐2‐ylidene and unsaturated imidazol‐2‐ylidene bearing symmetric aryl or benzyl substituents, while related dissymmetrically substituted imidazol(in)‐2‐ylidenes have not received sufficient attention . Therefore, a comparative experimental study of NHCs with Mes and CH 2 Mes substituents on the N atoms is presented.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Symmetric and dissymmetric N‐heterocyclic carbene rhodium(I) complexes: a comparative study of their catalytic activities in transfer hydrogenation reaction

Gülcemal

2012

Applied Organom Chemis

View full text Add to dashboard Cite

Six new [RhBr(NHC)(cod)] (NHC = N-heterocyclic carbene; cod = 1,5-cyclooctadiene) type rhodium complexes (4-6) have been prepared by the reaction of [Rh(m-OMe)(cod)] 2 with a series of corresponding imidazoli(in)ium bromides (1-3) bearing mesityl (Mes) or 2,4,6-trimethylbenzyl (CH 2 Mes) substituents at N 1 and N 3 positions. They have been fully characterized by 1 H, 13 C and heteronuclear multiple quantum correlation NMR analyses, elemental analysis and mass spectroscopy. Complexes of type [(NHC)RhBr(CO) 2 ] (NHC = imidazol-2-ylidene) (7b-9b) were also synthesized to compare s-donor/p-acceptor strength of NHC ligands. Transfer hydrogenation (TH) reaction of acetophenone has been comparatively studied by using complexes 4-6 as catalysts. The symmetrically CH 2 Mes-substituted rhodium complex bearing a saturated NHC ligand (5a) showed the highest catalytic activity for TH reaction.

show abstract

Section: Resultssupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Symmetric and dissymmetric N‐heterocyclic carbene rhodium(I) complexes: a comparative study of their catalytic activities in transfer hydrogenation reaction

Gülcemal

2012

Applied Organom Chemis

View full text Add to dashboard Cite

show abstract

“…38 4,5-dimethyl-1,3-diisopropyl-imidazol-2-ylidene copper chloride was prepared by following established literature methods for NHC CuCl. 39 4,5-dimethyl-1,3-diisopropyl-imidazol-2-ylidene 40 and 1,3-diisopropyl-imidazolinium chloride 41 were prepared according to literature. The diethyl ether adduct of lithium hexamethyldisilazide was prepared according to literature.…”

Section: Resultsmentioning

confidence: 99%

Deposition of Copper by Plasma-Enhanced Atomic Layer Deposition Using a Novel N-Heterocyclic Carbene Precursor

et al. 2013

View full text Add to dashboard Cite

Access to the full text of the published version may require a subscription. Rights AbstractTwo novel N-heterocyclic carbene (NHC)-containing copper(I) amides are reported as atomic layer deposition (ALD) precursors. 1,3-diisopropyl-imidazolin-2-ylidene copper hexamethyldisilazide (1) and 4,5-dimethyl-1,3-diisopropyl-imidazol-2-ylidene copper hexamethyldisilazide (2) were synthesized and structurally characterized. The thermal behaviour of both compounds was studied by thermogravimetric analysis (TGA), and they were both found to be reasonably volatile compounds. Compound 1 had no residual mass in the TGA and showed long-term stability at temperatures as high as 130 °C, while 2 had a residual mass of 7.4 %. Copper metal with good resistivity was deposited using 1 by plasma-enhanced atomic layer deposition. The precursor demonstrated self-limiting behaviour indicative of ALD, and gave a growth rate of 0.2 Å/cycle. Compound 2 was unsuccessful as an ALD precursor under similar conditions. Density functional theory calculations showed that both compounds adsorb dissociatively onto a growing copper film as long as there is some atomic roughness, via cleavage of the Cu-carbene bond.

show abstract

“…We developed a synthetic method for obtaining these known compounds [44,46,48,49,[52][53][54][55][56], which does not require the use of the isolated free carbenes or the use of the corresponding Ag(I)-NHC transmetallating agents. In general, the synthesis of 1-4 (Scheme 1) involved stirring of the respective 1,3diarylimidazolium or 1,3-diarylimidazolinium salt in toluene at 70 °C together with [RhCl(cod)]2 and K2CO3 as an efficient and mild base (A) [47] or with [Rh(OH)(cod)]2 (no base added; B). After removal of the toluene solvent the products were dissolved in CH2Cl2-ethyl acetate and purified by passing through a short silica column; complexes 1-4 were isolated in 58-88% yield.…”

Section: Synthesis and Characterization Of The [Rhcl(cod)(nhc)] Complmentioning

confidence: 99%

Selective Hydration of Nitriles to Corresponding Amides in Air with Rh(I)-N-Heterocyclic Complex Catalysts

Czégéni¹,

Udvardy

et al. 2020

Catalysts

View full text Add to dashboard Cite

A new synthetic method for obtaining [RhCl(cod)(NHC)] complexes (1–4) (cod = η4-1,5-cyclooctadiene, NHC = N-heterocyclic carbene: IMes, SIMes, IPr, and SIPr, respectively) is reported together with the catalytic properties of 1–4 in nitrile hydration. In addition to the characterization of 1–4 in solution by 13C NMR spectroscopy, the structures of complexes 3, and 4 have been established also in the solid state with single-crystal X-ray diffraction analysis. The Rh(I)-NHC complexes displayed excellent catalytic activity in hydration of aromatic nitriles (up to TOF = 276 h−1) in water/2-propanol (1/1 v/v) mixtures in air.

show abstract

Carbene Complexes Made Easily: Decomposition of Reissert Compounds and Further Synthetic Approaches

Cited by 34 publications

References 61 publications

Symmetric and dissymmetric N‐heterocyclic carbene rhodium(I) complexes: a comparative study of their catalytic activities in transfer hydrogenation reaction

Symmetric and dissymmetric N‐heterocyclic carbene rhodium(I) complexes: a comparative study of their catalytic activities in transfer hydrogenation reaction

Deposition of Copper by Plasma-Enhanced Atomic Layer Deposition Using a Novel N-Heterocyclic Carbene Precursor

Selective Hydration of Nitriles to Corresponding Amides in Air with Rh(I)-N-Heterocyclic Complex Catalysts

Contact Info

Product

Resources

About