A Donor‐Stabilized Zwitterionic “Half‐Parent” Phosphasilene and Its Unusual Reactivity towards Small Molecules |
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| Authors: | Kerstin Hansen Tibor Szilvási Dr Burgert Blom Dr Elisabeth Irran Prof?Dr Matthias Driess |
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| Institution: | 1. Department of Chemistry, Metalorganics and Inorganic Materials, Technische Universit?t Berlin, Strasse des 17. Juni 135, Sekr. C2, 10623 Berlin (Germany), Fax: (+49)?30‐314‐29734;2. Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, 1111 Budapest (Hungary) |
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| Abstract: | The stabilization of the labile, zwitterionic “half‐parent” phosphasilene 4 L′Si?PH (L′=CH(C?CH2)CMe(NAr)2]; Ar=2,6‐iPr2C6H3) could now be accomplished by coordination with two different donor ligands (4‐dimethylaminopyridine (DMAP) and 1,3,4,5‐tetramethylimidazol‐2‐ylidene), affording the adducts 8 and 9 , respectively. The DMAP‐stabilized zwitterionic “half‐parent” phosphasilene 8 is capable of transferring the elusive parent phosphinidene moiety (:PH) to an unsaturated organic substrate, in analogy to the “free” phosphasilene 4 . Furthermore, compounds 4 and 8 show an unusual reactivity of the Si?P moiety towards small molecules. They are capable of adding dimethylzinc and of activating the S?H bonds in H2S and the N?H bonds in ammonia and several organoamines. Interestingly, the DMAP donor ligand of 8 has the propensity to act as a leaving group at the phosphasilene during the reaction. Accordingly, treatment of 8 with H2S affords, under liberation of DMAP, the unprecedented thiosilanoic phosphane LSi?S(PH2) 16 (L=HC(CMe2,6‐iPr2C6H3N])2). Compounds 4 and 8 react with ammonia both affording L′Si(NH2)PH2 17 , respectively. In addition, the reaction of 8 with isoproylamine, p‐toluidine, and pentafluorophenylhydrazine lead to the corresponding phosphanylsilanes L′Si(PH2)NHR (R=iPr 18 a ; R=C6H5?CH3 18 b , R=NH(C6F5) 18 c ), respectively. |
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| Keywords: | phosphinidine phosphorus silanes silicon zwitterions |
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