A Donor‐Stabilized Zwitterionic "Half‐Parent" Phosphasilene and Its Unusual Reactivity towards Small Molecules. Issue 7 (16th January 2014)

• Record Type: Journal Article
• Authors: Hansen, Kerstin; Szilvási, Tibor; Blom, Burgert; Irran, Elisabeth; Driess, Matthias
• Is Part Of: Chemistry. Volume 20:Issue 7(2014)
• Page Start: 1947
• Page End: 1956
• Publication Date: 2014-01-16
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201303906
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The stabilization of the labile, zwitterionic "half‐parent" phosphasilene <bold>4</bold> L′SiPH (L′=CH[(CCH<sub>2</sub>)CMe(NAr)<sub>2</sub>]; Ar=2, 6‐<italic>i</italic>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>) 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 <bold>8</bold> and <bold>9</bold>, respectively. The DMAP‐stabilized zwitterionic "half‐parent" phosphasilene <bold>8</bold> is capable of transferring the elusive parent phosphinidene moiety (:PH) to an unsaturated organic substrate, in analogy to the "free" phosphasilene <bold>4</bold>. Furthermore, compounds <bold>4</bold> and <bold>8</bold> 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 H<sub>2</sub>S and the NH bonds in ammonia and several organoamines. Interestingly, the DMAP donor ligand of <bold>8</bold> has the propensity to act as a leaving group at the phosphasilene during the reaction. Accordingly, treatment of <bold>8</bold> with H<sub>2</sub>S affords, under liberation of DMAP, the unprecedented thiosilanoic phosphane LSiS(PH<sub>2</sub>) <bold>16</bold> (L=HC(CMe[2, 6‐<italic>i</italic>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>N])<sub>2</sub>). Compounds <bold>4</bold> and <bold>8</bold> react with ammonia both affording L′Si(NH<sub>2</sub>)PH<sub>2</sub><bold>17</bold>, respectively. In addition, the reaction of <bold>8</bold> with isoproylamine, <italic>p</italic>‐toluidine, and pentafluorophenylhydrazine lead to the corresponding phosphanylsilanes L′Si(PH<sub>2</sub>)NHR (R=<italic>i</italic>Pr <bold>18 a</bold>; R=C<sub>6</sub>H<sub>5</sub>CH<sub>3</sub><bold>18 b</bold>, R=NH(C<sub>6</sub>F<sub>5</sub>) <bold>18 c</bold>), respectively.</p> </abstract>