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Addition of Nucleophiles to Phosphanido Derivatives of Pt(III): Formation of P-C, P-N, and P-O Bonds
Andersson Arias, Juan Forniés, Consuelo Fortuño, Susana Ibáñez, Antonio Martín, Piero Mastrorilli, Vito Gallo, and Stefano Todisco
Inorg. Chem. 2013, 52, 11398-11408
DOI: 10.1021/ic401689c
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The reactivity of the dinuclear platinum(III) derivative [(RF)2PtIII(μ-PPh2)2PtIII(RF)2](Pt-Pt) (RF = C6F5) (1) toward OH-, N3-, and NCO- was studied. The coordination of these nucleophiles to a metal center evolves with reductive coupling or reductive elimination between a bridging diphenylphosphanido group and OH-, N3-, and NCO- or C6F5 groups and formation of P-O, P-N, or P-C bonds. The addition of OH- to 1 evolves with a reductive coupling with the incoming ligand, formation of a P-O bond, and the synthesis of [NBu4]2[(RF)2PtII(μ-OPPh2)(μ-PPh2)PtII(RF)2] (3). The addition of N3- takes place through two ways: (a) formation of the P-N bond and reductive elimination of PPh2N3 yielding [NBu4]2[(RF)2PtII(μ-N3)(μ-PPh2)PtII(RF)2] (4a) and (b) formation of the P-C bond and reductive coupling with one of the C6F5 groups yielding [NBu4][(RF)2PtII(μ-N3)(μ-PPh2)PtII(RF)(PPh2RF)] (4b). Analogous behavior was shown in the addition of NCO- to 1 which afforded [NBu4]2[(RF)2PtII(μ-NCO)(μ-PPh2)PtII(RF)2] (5a) and [NBu4][(RF)2PtII(μ-NCO)(μ-PPh2)PtII(RF)(PPh2RF)] (5b). In the reaction of the trinuclear complex [(RF)2PtIII(μ-PPh2)2PtIII(μ-PPh2)2PtII(RF)2](PtIII-PtIII) (2) with OH- or N3-, the coordination of the nucleophile takes place selectively at the central platinum(III) center, and the PPh2/OH- or PPh2/N3- reductive coupling yields the trinuclear [NBu4]2[(RF)2PtII(μ-Ph2PO)(μ-PPh2)PtII(μ-PPh2)2PtII(RF)2] (6) and [NBu4][(RF)2Pt1(μ3-Ph2PNPPh2)(μ-PPh2)Pt2(μ-PPh2)Pt3(RF)2](Pt2-Pt3) (7). Complex 7 is fluxional in solution, and an equilibrium consisting of Pt-Pt bond migration was ascertained by 31P EXSY experiments.
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