Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin‐2‐ylidene Ligands

Jahnke, Mareike C.; Pape, Tania; Hahn, F. Ekkehardt

doi:10.1002/zaac.201000234

Cited by 16 publications

(6 citation statements)

References 74 publications

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“…The Au-C NHC (2.016(2)Å) as well as the Au-C14 (1.988(2)Å) bond lengths of 1 fall in the range previously reported for similar mixed NHC/acetylide gold(I) complexes featuring a benzimidazolin-2-ylidene ligand [45]. Complex 2 exhibits, as expected, almost linear C1-Au-C14 (177.01 (9) • ) and Au-C14-C15 (177.5 (2) [47], which have been observed for many other gold carbene complexes [43,44], are observed for 1.…”

Section: Resultssupporting

confidence: 53%

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Ligand Exchange at a Gold(I) Carbene Complex

Jahnke

Pape

Hahn

2013

Zeitschrift Für Naturforschung B

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Section: Resultssupporting

confidence: 53%

“…The halide exchange of the chloro ligand in (N,Ndipropylbenzimidazolin-2-ylidene)gold(I) chloride 1 with a bromo ligand proceeds readily [44]. Thus the exchange of the chloro ligand with other ligands was studied.…”

Section: Resultsmentioning

confidence: 99%

Ligand Exchange at a Gold(I) Carbene Complex

Jahnke

Pape

Hahn

2013

Zeitschrift Für Naturforschung B

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“…Table ). This shift is in good agreement with data for previously reported NHC–gold(I) halide complexes and is likely a result of the lower acidity of the gold(I) ion in the bromide species, because the electronegativity of bromine is lower than that of chlorine. Both 1 Cl and 1 Br could be crystallized by slow diffusion of diethyl ether into dichloromethane solutions of the compounds.…”

Section: Resultssupporting

confidence: 91%

Gold(I), Gold(III), and Heterometallic Gold(I)–Silver(I) and Gold(I)–Copper(I) Complexes of a Pyridazine-Bridged NHC/Pyrazole Hybrid Ligand and Their Initial Application in Catalysis

et al. 2012

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The pyridazine-bridged NHC/pyrazole ligand L (HL = 3-[3-(2,4,6-trimethylphenyl)-3H-imidazolium-1-yl]-6-(3,5-dimethylpyrazol-1-yl)-pyridazine) that provides an organometallic and a classical N-donor compartment is shown to serve as a versatile scaffold for a variety of homo- and heterometallic gold(I) carbene complexes. Complexes [LAuX] (1 Cl , X = Cl; 1 Br , X = Br), [L2Au](PF6) (2), [L2AuAg](BF4)(PF6) (3), [L2AuAg3(MeCN)6](BF4)4 (5), and [L2AuCu](OTf)0.75(PF6)1.25 (6) have been characterized by X-ray crystallography. In all cases Au(I) binds to the NHC site while the additional Ag(I) in 3 or Cu(I) in 6 is accommodated in the pyrazole-derived site. Both 3 and 6 form two-stranded helical structures; racemization of the P and M enantiomers is much more facile in the Ag(I) case 3 but has a barrier of around 65 kJ/mol in the Cu(I) case 6, which is rationalized on the basis of the different coordination chemistry preferences of these two metal ions. 3 may bind two further Ag(I) ions to the central pyridazine N, giving 5. Treatment of 1 Br with Br2 leads to bromination at the pyrazole C4 of the ligand backbone, yielding [LBrAuBr] (8). In contrast, 1 Cl could be successfully oxidized to the Au(III) complex [LAuCl3] (7) using PhICl2; both 7 and the gold(I) complex 8 have been characterized crystallographically. Preliminary screening shows that 7, in combination with AgBF4, is a good catalyst for the etherification of 1-indanol with a variety of alcohol substrates and shows significantly higher activity than the gold(I) catalyst 1 Cl .

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“…[8][9][10][11][12] Not surprisingly, the most common synthetic pathway to Au III -NHC complexes involves oxidative addition of halogens or halogen equivalents to Au I -NHC precursor complexes. 8,9,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Other procedures, such as carbene transfer between Ag I and Au III , 8 or reaction of imidazolium ions with Au III in the presence of base, 9,10 are usually complicated by reduction of Au III to Au I . However, Lu et al synthesized the Au III -tetracarbene complex 1 by treatment of HAuCl 4 with an Ag I -NHC complex.…”

Section: Introductionmentioning

confidence: 99%

Stable Au^III complexes with four N-heterocyclic carbene groups can be prepared in high yield directly from KAuCl₄

2017

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Gold(iii) N-heterocyclic carbene (NHC) complexes of form [Au(NHC)Cl]Cl were synthesized by reaction of KAuCl with bis- and tetrakis(imidazolium) salts in the presence of a mild base. Treatment of these complexes with KPF afforded four-coordinate Au complexes of form [Au(NHC)](PF). X-Ray crystallography showed the [Au(NHC)] cations in the hexafluorophosphate salts to have a square planar Au(NHC) moiety [AuC 2.024(4)-2.082(7) Å]. In the [Au(NHC)Cl] cations in the chloride salts, coordination about Au was tetragonally-distorted octahedral, the axial Au-Cl bonds being substantially longer [AuCl 3.148(2)-3.693(1) Å] than the equatorial Au-C bonds [AuC 2.024(4)-2.082(7) Å]. NMR and conductance studies suggested that the structures of the complexes seen in the solid state persisted in DMSO solution, except in one case where a chlorido ligand dissociated from [Au(NHC)Cl] to form [Au(NHC)Cl]. The Au(NHC) unit was surprisingly robust. An Au complex was found to undergo H/D exchange reactions in DO solution at 100 °C with no signs of decomposition detectable by H NMR spectroscopy.H NMR studies showed that various complexes containing Au(NHC) moieties underwent little or no decomposition when heated at 120 °C in DMSO-d for extended periods.

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Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin‐2‐ylidene Ligands

Cited by 16 publications

References 74 publications

Ligand Exchange at a Gold(I) Carbene Complex

Ligand Exchange at a Gold(I) Carbene Complex

Gold(I), Gold(III), and Heterometallic Gold(I)–Silver(I) and Gold(I)–Copper(I) Complexes of a Pyridazine-Bridged NHC/Pyrazole Hybrid Ligand and Their Initial Application in Catalysis

Stable Au^III complexes with four N-heterocyclic carbene groups can be prepared in high yield directly from KAuCl₄

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Synthesis and Characterization of Gold(I) and Gold(III) Complexes Derived from Benzimidazolin‐2‐ylidene Ligands

Cited by 16 publications

References 74 publications

Ligand Exchange at a Gold(I) Carbene Complex

Ligand Exchange at a Gold(I) Carbene Complex

Gold(I), Gold(III), and Heterometallic Gold(I)–Silver(I) and Gold(I)–Copper(I) Complexes of a Pyridazine-Bridged NHC/Pyrazole Hybrid Ligand and Their Initial Application in Catalysis

Stable AuIII complexes with four N-heterocyclic carbene groups can be prepared in high yield directly from KAuCl4

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Stable Au^III complexes with four N-heterocyclic carbene groups can be prepared in high yield directly from KAuCl₄