Gold(I) N-Heterocyclic Carbene and Carbazolate Complexes

Wang, Harrison M. J.; Vasam, Chandra Sekhar; Tsai, T. Y. R.; Chen, Shih-Hua; Chang, and A. H. H.; Lin, Ivan J. B.

doi:10.1021/om049221u

Cited by 159 publications

(107 citation statements)

References 94 publications

(51 reference statements)

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“…(Table 1), and are in agreement with the literature for gold(I) complexes [12,[20][21][22][23][24][25][26][27][28][29][30][31]. The Au-C carbene bond lengths in 1a (1.987(9) Å) and 1b (1.983(2) Å) are comparable with those found in substituted NHC gold(I) chloro complexes [12,[18][19][20][21][22][23], and suggest a single bond character, in good agreement with the strong σ-donor character of CAACs. The cationic complexes 2d and 2e have slightly longer Au-C carbene bond lengths [2.0321(11) and 2.033(4) Å, respectively] in the range observed for cationic dicarbene (NHC) gold(I) complexes [24][25][26][27][28][29][30][31].…”

Section: Stable Carbenes; Carbene Complexes; Goldsupporting

confidence: 88%

Cyclic (alkyl)(amino)carbene gold(I) complexes: A synthetic and structural investigation

Frey

Dewhurst

Kousar

et al. 2008

Journal of Organometallic Chemistry

128

101

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A series of mono-and dicarbene gold(I) complexes of types Au(CAAC)(Cl) [CAAC = cyclic (alkyl) (amino)carbene] (1) and [Au(CAAC) 2 ] + [X] -(X = Cl, AuCl 2 ) (2) have been prepared through reaction of AuCl(SMe 2 ) with free carbenes a-e, and structurally characterized by single X-ray diffraction studies (1a, 1b, 2d, 2e). In addition two new free cyclic (alkyl)(amino)carbenes (c and e) have been synthesized. Keywords Stable Carbenes; Carbene Complexes; GoldFollowing the discovery of the first stable derivatives [1,2], singlet carbenes have received considerable attention as ligands for transition metals [3,4]. Carbenes feature a strong σ-donating ability, and strongly bind metal centers of high and low oxidation states [5]. Additionally, the possibility to tune their electronic and steric properties by variation of substituents [6], make carbenes versatile ligands for transition metal catalysts [7]. Since the Au(I) catalyzed asymmetric aldol reaction was published in the late 1980s [8], the use of Au (I) complexes in catalysis has received a lot of attention [9,10]. The first NHC substituted neutral and cationic gold(I) complexes were published in 1989 [11], and their application in catalysis stated in 2003 [12].We have already reported the synthesis and isolation of well-defined cyclic (alkyl)(amino) carbenes (CAAC) [13a], their use for the activation of small molecules [13b-d], their properties as ligand for transition metals [13e,f], and recently the preparation of a CAAC gold(I) complex, which allows for the catalytic formation of allenes, starting from enamines and alkynes [14]. This manuscript describes the synthesis and characterization of a series of Au(I) complexes, featuring one or two CAACs, depending on the bulkiness of the carbene ligand.The free carbenes (a-e) including the new ones (c and e) were readily prepared by deprotonation with LDA of the corresponding iminium salts; the latter were synthesized using the hydroiminiumation route [15] as shown in Scheme 1.The gold complexes 1a-d were then cleanly prepared by stirring the free carbenes a-d overnight in darkness in THF with AuCl(SMe 2 ), the same procedure used for the corresponding NHC complexes [16]. After removing the solvent under vacuum and washing with hexanes, the * To whom correspondence should be addressed. E-mail: gbertran@mail.ucr.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Under the same reaction conditions, a different behavior was observed for carbene e. In this case the reaction of a stoichiometric amount of e with AuCl(SMe 2 ) did not afford the expected mono-carbene gold c...

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Section: Stable Carbenes; Carbene Complexes; Goldsupporting

confidence: 88%

Cyclic (alkyl)(amino)carbene gold(I) complexes: A synthetic and structural investigation

Frey

Dewhurst

Kousar

et al. 2008

Journal of Organometallic Chemistry

128

101

View full text Add to dashboard Cite

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“…The average Au1-C1 and Au1-Cl1 bond lengths of 1.985(9) Å and 2.289(2) Å respectively are comparable to those reported for other Au(I)-NHC complexes. 48,[62][63][64] The average C1-Au1-Cl1 bond angle of figure 4 and was found to be similar to that of the recently described 65 …”

Section: A C C E P T E D Accepted Manuscriptsupporting

confidence: 82%

Some insights into the gold-catalysed A 3 -coupling reaction

Price

Brisdon

Randall

et al. 2017

Journal of Organometallic Chemistry

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Abstract.A series of cyclometallated and functionalised NHC gold(I) and gold(III) complexes, many of which feature chiral ligands, and their application to A 3 -coupling reactions is presented. Gold(III) complexes were found to be particularly effective catalysts for the coupling in a range of solvents, however no asymmetric induction was obtained when using chiral gold complexes and the rate of product formation was found to be similar even when using different ligand systems. In-situ NMR analysis of these reactions indicates that decomposition of the catalyst occurs during the course of the reaction while TEM studies revealed the presence of gold nanoparticles in crude reaction mixtures. Taken together these data suggest that the gold nanoparticales, rather than the intact gold complexes, could be the catalytically active species, and if so this may have significant implications for other gold-catalysed systems.Dedicated to Dr. Mark Whiteley (an outstanding colleague) on his retirement from the School of Chemistry, University of Manchester.

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“…Moreover, it shows the geometry around the Au(I) center is almost linear with a C carbene -Au-Cl angle of approximately 175.88 (7) • . The C carbene -Au and Au-Cl distances are 1.985(5) Å and 2.287(0) Å, respectively, typical to those reported for previous complexes containing a simple carbene ligand [15,23,24]. In addition, the planes of the imidazole-2-ylidene moiety and the NI moiety show an angle of approximately of 65.81 (8) • .…”

Section: X-ray Molecular Structure Of the N-heterocyclic Gold Carbenesupporting

confidence: 79%

“…Inorganics 2017, 5, 58 4 of 11 complexes containing a simple carbene ligand [15,23,24]. In addition, the planes of the imidazole-2-ylidene moiety and the NI moiety show an angle of approximately of 65.81(8)°.…”

Section: Photophysical Propertiesmentioning

confidence: 99%

N-Heterocyclic Carbene Coinage Metal Complexes Containing Naphthalimide Chromophore: Design, Structure, and Photophysical Properties

et al. 2017

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A series of novel N-heterocyclic carbene coinage metal complexes containing a naphthalimide (NI) chromophore has been prepared and fully characterized. Two types of molecules are described those where the NI unit is directly attached to the carbene unit with the general formulae [(L 1 )-M-X], M = Cu, X = Cl (1a); M = Ag, X = I (1b) and M = Au, X = Cl, (1c). While in the second family, a π-extended carbene ligand precursor L 2 -H + I − (3) was prepared where the NI unit is distant from the imidazole unit via a phenyl-alkyne bridge. Only two N-heterocyclic carbene metal complexes were prepared [(L 2 )-M-Cl], M = Cu (2a) and M = Au (2c). The related silver carbene compound could not be isolated. The molecular structure of the carbene complex 1c was determined and confirmed the formation of the target compound. Interestingly, the structure shows the presence of an aurophilic interaction Au···Au at 3.407 Å between two individual molecules. The photophysical properties of the compounds were investigated in solution at room temperature. Preliminary results suggested that all compounds are luminescent and act as blue emitters (420-451 nm). These transition emissions can be attributed to the intraligand origin of the NI chromphore. Moreover, the carbene complexes featuring L 2 ligand with π-extended system were found to be more luminescent.

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Gold(I) N-Heterocyclic Carbene and Carbazolate Complexes

Cited by 159 publications

References 94 publications

Cyclic (alkyl)(amino)carbene gold(I) complexes: A synthetic and structural investigation

Cyclic (alkyl)(amino)carbene gold(I) complexes: A synthetic and structural investigation

Some insights into the gold-catalysed A 3 -coupling reaction

N-Heterocyclic Carbene Coinage Metal Complexes Containing Naphthalimide Chromophore: Design, Structure, and Photophysical Properties

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