Synthesis and Reactions of Pd II Complexes with Aryl, Aroyl, and Iminoaroyl Ligands – Insertion of CO and RNC into the Pd–Ar Bond and Intermolecular Coupling of the Ligands

Abstract

The arylpalladium(II) complexes [PdIAr(bpy)] (Ar = Ph, C6H3-3,5-Me2, C6H4-4-OMe, C6H4-2-OMe, C6H4-4-C6H4-4-I, 1-naphthyl; bpy = 2,2′-bipyridine) undergo insertion of CO and CNR (R = tBu, C6H3-2,6-Me2) into the Pd–aryl bond to produce [PdI(COAr)(bpy)] and [PdI{C(=N–R)Ar}(bpy)]. The dinuclear complex [C6H3-3,5-{(OCH2CH2)2C6H4-3-PdI(bpy)}2] is synthesized by the oxidative addition reaction of 1,3-bis[(3-iodophenyl)-1,4,7-trioxaheptyl]benzene to [Pd(dba)2] (dba = dibenzylideneacetone). The addition of AgBF4 to the arylpalladium(II) complexes [PdIAr(bpy)] (Ar = C6H4-4-OMe, C6H4-2-OMe, 1-naphthyl) produces the intermolecular coupling products of the aryl ligands, Ar–Ar. The reactions of AgBF4 with the aroylpalladium(II) complexes [PdI(COAr)(bpy)] (Ar = C6H3-3,5-Me2, C6H4-2-OMe) result in decarbonylation and intermolecular coupling of the ligands to yield the diarylketones. The iminoaroylpalladium(II) complex [PdI{C(=NtBu)C6H3-3,5-Me2}(bpy)] undergoes hydrolysis of the ligand to yield tBuNHCO(C6H3-3,5-Me2). The addition of AgBF4 to the dinuclear complex [C6H3-3,5-{(OCH2CH2)2C6H4-3-PdI(bpy)}2] yields a mixture of the cyclic oligomers cyclo-[C6H3-3,5-{(OCH2CH2)2C6H4-3-}2]n (n = 1–4) by inter- and intramolecular coupling of the aryl ligands.