Thermal reaction of white phosphorus with [(triphos)RhH3] (1) in THF affords [(triphos)Rh(η1:η2‐P4H)] (2), triphos=MeC(CH2PPh2)3. Similar complexes [(triphos)Rh(η1:η2‐P4R)] (R=Me (7), Et (8), Ph (9)) also form at lower temperature by the reaction of P4 and [(triphos)Rh(R)(η2‐C2H4)] with elimination of ethene. In contrast, a double‐insertion process follows the reaction of [(triphos)Rh(H)(η2‐C2H4)] and P4 to generate tetraphosphido ethyl complex 8. Compounds 2, 7, 8 and 9 are thermally unstable and eventually decompose into the cyclotriphosphorus complex [(triphos)Rh(η3‐P3)] (3) plus other unidentified phosphorus‐containing species. Otherwise, PH3 or PH2R is generated in the presence of H2. The formation of PH3 and 3 is quantitative starting from the precursor 2. The electrophilic attack of MeOTf or HBF4 on the P4R ligand in the complexes 2, 7–9 is regioselective, and yields a cationic product of formula [(triphos)Rh(η1:η2‐P4RR′)]+. The direct attack on the substituted p‐R phosphorus atom is demonstrated by crossing experiments. Complexes of the latter type have been isolated in the solid state for the combinations R=H and R′=Me (11) or R=Ph and R′=Me (12). The latter species, [(triphos)Rh(η1:η2‐P4PhMe′)]OTf⋅2 CH2Cl2 (OTf=triflate), has been characterised by X‐ray methods. The geometry at the metal is better described as a trigonal bipyramidal than pseudo‐octahedral. In fact, the P4RR′ unit acts as a bidentate ligand with its exocyclic PR2 donor group and the endocyclic, dihapto‐coordinated PP linkage. The latter group lies in the equatorial plane, in a similar way to a classic olefin ligand that is coordinated to a butterfly‐shaped L4M fragment (M=d8). DFT calculations on a model of 2 and all possible protonated isomers confirm that double substitution at the exocyclic P‐donor positions of the open P4 unit is energetically favoured. A multinuclear and multidimensional NMR analysis confirms that this structure is maintained in solution for both the parent and the protonated compounds.

The metal‐promoted functionalisation of the white phosphorus tetrahedron is obtained from the reaction of a variety of rhodium precursors, which include the trihydride [(triphos)RhH3] and the alkyl and aryl complexes [(triphos)Rh(R)(C2H4)] (R = H, Me, Et, Ph; triphos = MeC(CH2PPh2)3). The [(triphos)Rh(η1:η2‐P4R)] complexes, which contain the unprecedented hydrido‐, alkyl‐ or aryl‐tetraphosphido ligands P4R−, undergo regioselective electrophilic attack from H+ or Me+ to yield the salts [(triphos)Rh(η1:η2‐P4RR′)]Y (R′ = H, Me; Y = BF4, OSO2Tf). This reaction represents the first example in which PH and PC bonds are formed starting from white phosphorus through the mediation of a transition‐metal complex (see scheme).

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{{Explor lien
   |wiki=    Wicri/Sarre
   |area=    MusicSarreV3
   |flux=    Istex
   |étape=   Corpus
   |type=    RBID
   |clé=     ISTEX:282CB81A56794D5553A18BC2CA70B00CFD8B47E3
   |texte=   Activation and Functionalization of White Phosphorus at Rhodium: Experimental and Computational Analysis of the [(triphos)Rh (η1:η2‐P4RR′)]Y Complexes (triphos=MeC(CH2PPh2)3; R=H, Alkyl, Aryl; R′=2 Electrons, H, Me)
}}