Structure and Properties of Neutral and Cationic Gold(III) Complexes from Substituted 2-(2′-Pyridyl)quinoline Ligands

Abstract

A one-step catalytic synthesis of 6-substituted 4-phenyl-2-(2'-pyridyl)quinolines provides electronically differentiated ligands without solvent, inert atmosphere, metal contamination, or chromatography. Gold(III) complexes formed from these bidentate PyQuin ligands were characterized and studied by single-crystal X-ray diffraction. The cationic gold(III) chloride synthesized from 6-methoxy-4-phenyl-2-(2'-pyridyl)quinoline has a distorted square-planar ligand environment. Diamagnetic neutral gold(III) complexes from methoxy-, methyl-, and phenyl-PyQuin ligands exhibit a long axial Au-N2 interaction.

Cyclometalated Gold(III) Complexes: Synthesis, Reactivity, and Physicochemical Properties

“…[109] In 2010, Jurisson and co-workers described the synthesis and radiotherapeutic study of bis(thiosemicarbazonato) Au III complex 129,w hich was prepared by the reaction of the thiosemicarbazone ligand with NaAuCl 4 in ethanol. [112] Recently,Y ou and co-workers reported that [Au(bpy)Cl 2 ] + Cl À (bpy = 2,2'-bipyridine) complexes are the best catalysts for the synthesis of 3-alkynyl furans and pyrroles. [111] In 2014, Larsen and co-workers showed that the reaction of 6-methoxy-4-phenyl-2-(2'-pyridyl)quinoline (MeO-Py-Quin) with NaAuCl 4 in the presence of AgBF 4 (1 equiv) at 90 8 8Ci na cetonitrile delivered complex [(N^N)AuCl 3 ] 131 (N^N = MeO-Py-Quin).…”

“…Addition of two equivalents of AgBF 4 afforded ac ationic gold(III) complex. [112] Recently,Y ou and co-workers reported that [Au(bpy)Cl 2 ] + Cl À (bpy = 2,2'-bipyridine) complexes are the best catalysts for the synthesis of 3-alkynyl furans and pyrroles. [113] Some of these complexes have also been used as chemical probes to study reductive elimination, as shown by Vicic and co-workers.…”

“…In 2014, Larsen and co‐workers showed that the reaction of 6‐methoxy‐4‐phenyl‐2‐(2′‐pyridyl)quinoline (MeO‐Py‐Quin) with NaAuCl 4 in the presence of AgBF 4 (1 equiv) at 90 °C in acetonitrile delivered complex [(N^N)AuCl 3 ] 131 (N^N=MeO‐Py‐Quin). Addition of two equivalents of AgBF 4 afforded a cationic gold(III) complex . Recently, You and co‐workers reported that [Au(bpy)Cl 2 ] + Cl − (bpy=2,2′‐bipyridine) complexes are the best catalysts for the synthesis of 3‐alkynyl furans and pyrroles …”

Oxidative annulations via double CH bond cleavages: Approach to quinoline derivatives

“…Quinoline and its derivatives are extensively existed skeletons in privileged heterocyclic scaffold systems and represent the typical class of heterocycles. They have been widely used in the pharmaceuticals, synthons, [1] ligands, [2] and so forth. Some pharmaceutical molecules containing quinoline structures are shown in Scheme 1.…”

Coinage metal complexes of N‐heterocyclic carbene bearing nitrile functionalization: Synthesis and photophysical properties

“…The NHC‐based Au(I) complexes [XAu(I)(NHC)] or [Au(I)(NHC) 2 ]X presumably exist in various structural motifs, depending on the types of substituent attached to the NHC ligand . The Au(I) ions in Au(I)–NHC complexes are known to have two possible oxidation states of either +1 or +3, and linear, trigonal planar and tetrahedral geometries are known . The Au(I) complexes that can exist as mononuclear and polynuclear complexes with one or more NHC moieties per ligand can generate a strong linear coordination bond between Au(I) and carbene carbon to facilitate the formation of Au(I)–NHC complexes.…”