Gold(I) Complexes of P,N Ligands and Their Catalytic Activity

Abstract

Gold(I) complexes were readily prepared by reaction of the respective ligands with (Me2S)AuCl in CH2Cl2. Complexes of formula LAuCl {L = diphenyl(2‐pyridyl)phosphane (PPh2Py), (R)‐(+)‐4‐[(2)‐(diphenylphosphanyl)‐1‐naphthyl]‐N‐[(R)‐1‐phenylethyl]‐1‐phthalazinamine (PINAP)} were obtained when a 1:1 molar ratio of ligand to starting gold precursor was used. When a 2:1 ratio of ligand to gold precursor was used with PPh2Py or MandyPhos as ligands, complexes of the type L2AuCl were obtained. All complexes were fully characterized, and single‐crystal X‐ray structures could be determined for four complexes. Chloride ions were removed by reaction with silver salts, such as AgNTf2, AgOTf and AgBF4, for the use of these complexes as catalysts. After the catalytic reaction with alkynes and alcohols in acetonitrile, a unique trinuclear gold(I) complex derived from [(PPh2Py)Au]BF4 could be characterized by X‐ray structural analysis, showing a mode of catalyst deactivation.

Highly Efficient One-Pot Synthesis of 2,4-Disubstituted Thiazoles Using Au(I) Catalyzed Oxidation System at Room Temperature

“…It can be seen that Mor-DalPhosAuCl exhibited the good yield of 58% with the presence of AgNTf 2 , and Me-DalPhosAuCl showed the slightly inferior yield of 53%, due to the steric size of the pendant secondary amine [28]. These prospective results were consistent with our previous works, which further supported the accepted viewpoint that P,N-bidentate ligands could attenuate the strong electrophilicity of the a-oxo gold carbene via the formation of a tricoordinated metal center [29,30]. L1AuCl and L2AuCl, with the more rigid cyclic structure, displayed less-efficient yield in this reaction.…”

Insights into the mechanism for gold catalysis: behaviour of gold(i) amide complexes in solution

“…1,6 Many tri-and tetra-coordinate gold complexes have been reported. [2][3][4][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Most notably, Hashmi reported the X-ray crystallographic characterisation of a tri-coordinate gold(I) complex L 2 AuX, 5,9 and many polynuclear auracyclic complexes featuring bidentate ligands have been described extensively and such systems often include Au-Au interactions. 8 For all the evidence for complexes which, in the solid state, display coordination numbers for gold that exceed two, the rationalisation of gold catalysis in solution rarely invokes species with coordination numbers that exceed two unless they are hypothesised in transition states of complex-induced activation reactions.…”

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

“…CCDC 889456 (4), 889457 (5), 943937 (9), 943938 (11), 943935 (12) and 943936 (14) contain the supplementary crystallographic data for this paper. These files can be obtained, free of charge, from the CCDC via www.ccdc.cam.ac.uk/data_request/cif.…”

“…12,13 Despite the ever burgeoning literature concerning gold-catalysed reactions, the majority of structurally defined chiral gold complexes are restricted to those bearing chiral phosphane ligands. [14][15][16][17][18][19] Given the fact the use of gold-NHC complexes [20][21][22][23][24][25][26] is now de rigour in synthesis, it is somewhat surprising that reports of structurally characterised, chiral, Au(I)-NHC [27][28][29][30][31][32][33][34][35][36] and Au(I)-ADC/NAC 37 complexes are still comparatively scarce. Likewise, the synthesis and characterisation and catalytic activity of cyclometallated gold(III) complexes is relatively unexplored, with only a handful of examples being cited in the literature.…”