| Abstract
| - Gold nanoparticles (<2 nm) stabilized by poly(N-vinyl-2-pyrrolidone) (Au:PVP NPs) were prepared byreduction of AuCl4- with NaBH4 in the presence of PVP and characterized via an array of methods includingoptical absorption spectroscopy, transmission electron microscopy, X-ray diffraction, X-ray absorptionnear-edge structure, extended X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Wedemonstrate for the first time that the Au:PVP NPs act as catalyst toward homocoupling of phenylboronicacid in water under aerobic conditions. Suppression of biphenyl formation under anaerobic conditionsindicates that molecular oxygen dissolved in water is intimately involved in the coupling reactions. Amechanism of the aerobic homocoupling catalyzed by the Au:PVP NPs is proposed on the basis of a crucialrole of dissolved oxygen, steric effects on the product yields, and the well-established mechanism for thePd(II)-based catalysts.
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