NHC-stabilized copper(I) aryl complexes and their transmetalation reaction with aryl halides

Tris(pentafluoroethyl)difluorophosphorane: A Versatile Fluoride Acceptor for Transition Metal Chemistry

“…Twoo ft hese units form the dimeric structure of the dicationo f4.S uch h n coordination of the metal atom to aryl substituents at the NHC imidazoline nitrogen atoms is rather common,a so bserved, fore xample, for the low-valent, dinuclear NHC complexes [{(Ar 2 Im)M} 2 ]( Ar = Mes, M = Fe;A r = Dipp, M = Co, Ni) [54] and [{(Dipp 2 Im)IrH} 2 ] 2 + 2[BF 4 ] À , [55] in which each NHC ligand is end-on coordinated to the metal center and one of the aryl substituents is attached through the p system to the adjacent metal atom. The CuÀC distance to the carbenic carbon atom of 1.890(4) in compound 4 is slightly longert han the distances observed in the parentf luoride complex [(Dipp 2 Im)CuF] (1.857(3) ) [56] and the tert-butoxide complex [(Dipp 2 Im)Cu(OtBu)] (1.8641( 18) ) [57] but shortert han those in the related chloride complex [(Dipp 2 Im)CuCl] (1.953( 8) ) [53c] or in the bis-NHC complexes [(Dipp 2 Im) 2 Cu][PF 6 ]( 1.938( 5) )a nd [(Dipp 2 Im) 2 Cu][BF 4 ] (1.939 (18) ). [58] The CuÀCd istance to the ipso carbona tomC 2 (2.156(4) )i ss ignificantly shortert han the distances to the carbon atoms in ortho positions C3 and C4 (2.312(5) and 2.355(5) ,r espectively).…”

N-Heterocyclic carbene and cyclic (alkyl)(amino)carbene complexes of vanadium(iii) and vanadium(v)

“…The intensely blue colored solutions of [VCl 3 (L)] (L = NHC, cAAC Me ) discolor after a few hours at 80 °C in C 6 D 6 in the presence of CuCl, and the formation of [(L)CuCl] (L = NHC, cAAC Me ) was observed. 23 For example, a mixture of [VCl 3 (IMes)] 2 and CuCl in boiling C 6 D 6 led to formation of [(IMes)CuCl], which was identified by spectroscopy and X-ray diffraction. This indicates that the formation of a Cu–C Carbene bond is favored compared to formation of a V–C carbene bond most probably due to an enhanced thermodynamic stability of the former.…”

A detailed theoretical investigation to unravel the molecular mechanism of the ligand-free copper-catalyzed Suzuki cross-coupling reaction

“…This pathway is predicted to be favored by many theoretical studies on Cu-catalyzed cross-coupling reactions. [78][79][80]94 The second pathway (Mechanism 2), considered a variant of Mechanism 1, begins by coordinating an alkynyl halide on the Cu catalyst in an η 2 mode. By playing the role of an ancillary ligand on the metal, the coordinated alkynyl halide promotes the transmetalation on the Cu(I) catalyst by aryl boronic acid.…”