Editing Oxonium ion (section)

==Gold-stabilized species==
[[File:Triphenylphosphinegoldoxonium.png|right|frameless]]
An unusually stable oxonium species is the gold complex tris[triphenylphosphinegold(I)]oxonium tetrafluoroborate, [(Ph<sub>3</sub>PAu)<sub>3</sub>O][BF<sub>4</sub>], where the intramolecular [[aurophilicity|aurophilic interactions]] between the gold atoms are believed responsible for the stabilisation of the cation.<ref>{{cite journal |first=Hubert |last=Schmidbaur |title=The Aurophilicity Phenomenon: A Decade of Experimental Findings, Theoretical Concepts and Emerging Application |journal=[[Gold Bulletin]] |year=2000 |volume=33 |issue=1 |pages=3–10 |doi=10.1007/BF03215477 |doi-access=free}}</ref><ref>{{cite journal |first=Hubert |last=Schmidbaur |title=Ludwig Mond Lecture: High-Carat Gold Compounds |journal=[[Chem. Soc. Rev.]] |year=1995 |volume=24 |issue=6 |pages=391–400 |doi=10.1039/CS9952400391}}</ref> This complex is prepared by treatment of Ph<sub>3</sub>PAuCl with [[silver oxide|Ag<sub>2</sub>O]] in the presence of [[sodium tetrafluoroborate|NaBF<sub>4</sub>]]:<ref>{{cite book |last1=Bruce |first1=M. I. |author-link1=Michael Ian Bruce |last2=Nicholson |first2=B. K. |last3=Bin Shawkataly |first3=O. |last4=Shapley |first4=J. R. |last5=Henly |first5=T. |chapter=Synthesis of Gold-Containing Mixed-Metal Cluster Complexes |year=1989 |title=Inorganic Syntheses |title-link=Inorganic Syntheses |volume=26 |pages=324–328 |editor-last=Kaesz |editor-first=Herbert D. |publisher=[[John Wiley & Sons, Inc.]] |doi=10.1002/9780470132579.ch59 |isbn=9780470132579}}</ref>

:3&nbsp;Ph<sub>3</sub>PAuCl + Ag<sub>2</sub>O + NaBF<sub>4</sub> → [(Ph<sub>3</sub>PAu)<sub>3</sub>O]<sup>+</sup>[BF<sub>4</sub>]<sup>−</sup> + 2&nbsp;AgCl + NaCl

It has been used as a catalyst for the propargyl [[Claisen rearrangement]].<ref>{{cite journal |last1=Sherry |first1=Benjamin D. |last2=Toste |first2=F. Dean |author-link2=F. Dean Toste |year=2004 |title=Gold(I)-Catalyzed Propargyl Claisen Rearrangement |journal=[[Journal of the American Chemical Society]] |volume=126 |issue=49 |pages=15978–15979 |doi=10.1021/ja044602k |pmid=15584728 |citeseerx=10.1.1.604.7272 |issn=0002-7863 |url=http://www.cchem.berkeley.edu/toste/publications/jacs12615978.pdf}}</ref>