Hypervalent, Low-Coordinate Phosphorus(III) Centers in Complexes of the Phosphadiazonium Cation with Chelate Ligands

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• 作者：Neil Burford ; Andrew D. Phillips ; Heather A. Spinney ; Michael Lumsden ; Ulrike Werner-Zwanziger ; Michael J. Ferguson ; and Robert McDonald
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：March 23, 2005
• 年：2005
• 卷：127
• 期：11
• 页码：3921 - 3927
• 全文大小：120K
• 年卷期：v.127,no.11(March 23, 2005)
• ISSN：1520-5126

文摘

Trifluoromethylsulfonyloxy-(2,4,6-tri-tert-butylphenylimino)phosphine, Mes*NPOTf (Mes* = 2,4,6-tri-tert-butylphenyl, OTf = trifluoromethanesulfonate, triflate) reacts quantitatively with the multifunctionalligands 2,2'-bipyridine (2,2'-BIPY), N,N,N',N'-tetramethylethylenediamine (TMEDA), 1,2-bis(diethylphosphino)ethane (DEPE), 1,2-bis(diphenylphosphino)ethane (DIPHOS), and N,N,N',N' ',N' '-pentamethyldiethylenetriamine (PMDETA) to give the Lewis acid-base complexes [Mes*NP(2,2'-BIPY)][OTf], [Mes*NP(TMEDA)][OTf], [Mes*NP(DIPHOS)][OTf], [Mes*NP(DEPE)][OTf], and [Mes*NP(PMDETA)][OTf], respectively.Single-crystal X-ray diffraction studies indicate that the closest contact of the ligand donor atoms occurs atphosphorus in all cases, affecting significant displacement of the OTf anion. The resulting cations [Mes*NP(L)]⁺ are best described as complexes of a neutral chelating ligand on a phosphadiazonium Lewis acceptor,and highlight the potential for electron-rich centers to behave as Lewis acids despite the presence of alone pair of electrons at the acceptor site. More importantly, the new complexes represent rare examplesof systems containing hypervalent, low-coordinate phosphorus(III) centers.