Gold(III) Adducts with Chiral Pyridinyl-Oxazolines. Synthesis, Reactivity of the Coordinated Ligands and Structural Characterizations

Novel gold(III) pyridinyl-oxazolilie cationic complexes [A U(pyox(R))Cl(2)[X] [pyox(R) 2-(pyridin-2-yl)-4,5-dihydrooxazole, with R = (i)Pr, Bn, and (R)-4-phenyl-2-(pyridin-2-yl)-4,5-dihydrooxazole; X = PF(6), AuCl(4), or mixtures of the two anions] were synthesized and Structurally characterized. Reaction of the adducts with NaOAc ill aqueous Solution afforded the neutral complexes [Au(N,N',O)Cl] of the deprotonated ligands N-(1-hydroxy-3-R-2-yl)pyridine-2-carboxamide (R = (i)Pr, Ph), N,N'H,OH, resulting from ring-opening of the bound pyox ligand by hydroxide ions and incorporation of hydroxide into the ring-opened products. Reaction of [Au(N,N',0)Cl] (R = (i)Pr) with FIX (X = Cl, BF(4), OTf) in aqueous Solution resulted in protonation of the coordinated alkoxo, group and its displacement from the coordination sphere to give the adducts [Au(N,N', OH)ClX] (X = OTf, Q or the aquo complex [Au(N,N',OH)(OH(2))Cl](+) (X = BF(4)). Crystal structure characterizations were carried out on both [Au(N,N',O)Cl] and [Au(N,N',OH)Cl(2)] (R = (i)Pr). Equimolar mixtures of the ring-opened derivative [Au(N,N',OH)Cl] (R = (i)Pr) and either silver salts or HBF(4) Were found to promote, Under Mild conditions, polymerization of styrenes.