| Abstract
| - 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.
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