Do Short C–H–M (M = Cu(I), Ag(I)) Distances Represent Agostic Interactions in Pincer-Type Complexes? Unusual NHC Transmetalation from Cu(I) to Ag(I)

Liu, Xianghao; Pattacini, Roberto; Deglmann, Peter; Braunstein, Pierre

doi:10.1021/om200033m

Cited by 58 publications

(35 citation statements)

References 68 publications

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“…The imidazolyl ring plane is almost perpendicular to the gold coordination plane. Albeit the picolyl moiety points in the direction of the C1–Au1–Br2 vector, no close cation–arene‐interactions between the pyridyl ring and the gold atom are present 20,21. The shortest Au–N3 distance is 3.25 Å, i.e.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Gold(III) Complexes Bearing a Picoline‐functionalized N‐Heterocyclic Carbene

Topf

Hirtenlehner

Fleck

et al. 2011

Zeitschrift anorg allge chemie

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3‐Methyl‐1‐(2‐picolyl)‐imidazolium chloride (1) has been synthesized and used as a precursor for the preparation of the (NHC)AgCl complex [NHC = 3‐methyl‐1‐(2‐picolyl)imidazol‐2‐ylidene] (2). Transmetalation of 2 with (tht)AuBr (tht = tetrahydrothiophene) yields the corresponding (NHC)AuBr complex 3, which is further oxidized by Br2 to give the (NHC)AuBr3 compound 4. Treatment of 4 with one equivalent of solid AgBF4 affords the [(NHC)AuBr2][BF4] congener 5 as a pale green, crystalline powder. The structure of 4 and 5 were determined by single‐crystal X‐ray diffraction, revealing for 5 a κ‐N‐coordination of the AuIII atom by the picolyl nitrogen atom. Further attempts to exchange all bromides by carboxylates results in the reduction to the dimeric AuI compound [(NHC)2Au2][BF4]2, 6.

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Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Gold(III) Complexes Bearing a Picoline‐functionalized N‐Heterocyclic Carbene

Topf

Hirtenlehner

Fleck

et al. 2011

Zeitschrift anorg allge chemie

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“…Several methods are known to access Cu(I)eNHC complexes, such as the use of Ag(I)eNHCs as transmetalating reagents, the reaction of free carbenes with Cu(I) halides, or of imidazolium salts with Cu(I) oxide [5,38]. Recently, Cu(I) bis-or multidentate-NHC complexes have attracted much attention and shown interesting redox behaviour [39], luminescence properties [40,41], ability to transmetalate their NHC ligand(s) to Ru [42], Rh [43], Pd [44,45], Ag [46], and Ni [47] precursors, and catalytic properties (Sonogashira reaction [48], nitrene and carbene transfer reactions [49]). Moreover, the nature of the metal-carbene bond in Cu(I)eNHC complexes has been the subject of theoretical studies [50,51] while copper belongs to the very few metals able to form clusters with bridging imidazolinylidenes [47].…”

Section: Introductionmentioning

confidence: 99%

Silver(I) and copper(I) complexes with bis-NHC ligands: Dinuclear complexes, cubanes and coordination polymers

Charra

Frémont

Breuil

et al. 2015

Journal of Organometallic Chemistry

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a b s t r a c tSilver(I) and copper(I) complexes containing neutral bis(N-heterocyclic carbene) (NHC) ligands and coordinated or non-coordinated chloride, bromide, iodide, or tetrafluoroborate anions, were synthesised. The nature of the anions impacts deeply the structural features of the complexes in the solid-state and neutral cubane-, neutral coordination polymer-, or dicationic bridged-type architectures have been characterised. The structures of (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)disilver(I) dichloride (2a), bis(m-1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene-k-C)tetra-m 3 -bromotetrasilver(I) (2b), bis(1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)disilver(I) tetrafluoroborate (2d) in 2d$CH 2 Cl 2 , (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene)dicopper(I) dichloride (3a) and (1,3-bis(3 0 -butylimidazol-2 0 -ylidene)benzene) dicopper(I) dibromide (3b) were established by X-ray diffraction. IntroductionSince the first stable free N-heterocyclic carbene (NHC) was isolated by Arduengo in 1991 [1], this class of ligands has found numerous applications in organometallic chemistry in particular for the preparation of new metal-based catalysts [2e9]. The first NHC silver(I) complex was prepared by Arduengo et al. by reaction between a free carbene and silver(I) triflate [10]. Today, the reaction of imidazol(in)ium salts with a variety of silver(I) precursors such as Ag 2 O [11], Ag(OAc) [12,13], Ag 2 CO 3 [14] or AgCl [15], with K 2 CO 3 or Na 2 CO 3 as external base, allows for the formation of Ag(I)eNHC complexes in high yields. Ag(I)eNHC complexes are stable towards air and moisture. The reaction of Ag 2 O with halide imidazol(in)ium salts, first described in 1998 by Lin, is particularly efficient to synthesise halide Ag(I)eNHC complexes under mild conditions, without having to handle free NHCs [11]. The second product formed following Lin's protocol being water, non-distilled solvents can be employed, which renders this approach very convenient and popular [11]. Ag(I)eNHC complexes are potent catalysts for e.g. the cycloaddition of CO 2 to terminal epoxides [16] and CeN coupling reactions [17]. During pharmacological studies, they proved to release in vivo slowly and steadily free silver cations acting as tumour cell killers or suppressants of infections [18e21]. Ag(I)e NHCs are mostly employed as transmetalating agents to access late transition metal NHC complexes, without the need to handle unwieldy free carbenes. They are indeed known to transmetalate efficiently their NHC ligand(s) to Cu [22], Ni [23,24] Pd [23,25], Pt [25] and Au [26,27] precursors. The coordination geometry around the Ag(I) centre tends to be linear. When the associated anion (X À ) is a halide, the formation of polynuclear complexes or clusters with XeAgeX bridge(s) can lead to a broad structural diversity in the solid-state. In Ag(I)eNHC clusters complexes, d 10 ed 10 interactions are often encountered [28,29], while the coordination geometry around the Ag(I) cations may deviate from linear to trigonal or even tetr...

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“…Different from those in 1 , there are still one disordered water molecule over two positions and they interact with the two Cu II ions in the dinuclear [Cu 2 (L) 2 (H 2 O)] unit from their axial positions with a rather long Cu–O distance [2.6074(4) Å]. For each Cu II ion in 2 , there is one phenyl hydrogen atom located on one of its axial positions with a H ··· Cu distance of 2.8843(3) Å, which is longer than those reported in documents 37,38…”

Section: Resultsmentioning

confidence: 84%

Synthesis and Structures of Two Dinuclear Transition Metal Complexes and Their Catalytic Applications in Hydrogenation of Ketones

Zeng

Cheng

et al. 2013

Zeitschrift anorg allge chemie

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The complexes [Ni 2 (L) 2 ] 2 ·H 2 O (1) and [Cu 2 (L) 2 (H 2 O)]· 2CH 3 OH (2) were prepared by reaction of the chiral Schiff base ligand N-[(1R,2S)-2-hydroxy-1,2-diphenyl]-acetylacetonimine (H 2 L) with Ni II and Cu II ions, respectively, aiming to develop economically and environmentally-friendly catalysts for the hydrogenation of ketones. They have a dinuclear skeleton with axial vacant sites. The catalytic effects of the two complexes for hydrogenation of ketones were tested using dihydrogen gas as hydrogen source. They present some catalytic

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Do Short C–H–M (M = Cu(I), Ag(I)) Distances Represent Agostic Interactions in Pincer-Type Complexes? Unusual NHC Transmetalation from Cu(I) to Ag(I)

Cited by 58 publications

References 68 publications

Synthesis and Characterization of Gold(III) Complexes Bearing a Picoline‐functionalized N‐Heterocyclic Carbene

Synthesis and Characterization of Gold(III) Complexes Bearing a Picoline‐functionalized N‐Heterocyclic Carbene

Silver(I) and copper(I) complexes with bis-NHC ligands: Dinuclear complexes, cubanes and coordination polymers

Synthesis and Structures of Two Dinuclear Transition Metal Complexes and Their Catalytic Applications in Hydrogenation of Ketones

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