Addition of nucleophiles to phosphanido derivatives of Pt(III): Formation of P-C, P-N, and P-O bonds

Abstract

The reactivity of the dinuclear platinum(III) derivative [(R F)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[(R F)2PtII(μ-OPPh2)(μ-PPh 2)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][(R F)2PtII(μ-N3)(μ-PPh 2)PtII(RF)(PPh2RF)] (4b). Analogous behavior was shown in the addition of NCO- to 1 which afforded [NBu4]2[(RF)2Pt II(μ-NCO)(μ-PPh2)PtII(RF) 2] (5a) and [NBu4][(RF)2Pt II(μ-NCO)(μ-PPh2)PtII(R F)(PPh2RF)] (5b). In the reaction of the trinuclear complex [(RF)2PtIII(μ-PPh 2)2PtIII(μ-PPh2) 2PtII(RF)2](PtIII-Pt III) (2) with OH- or N3 -, the coordination of the nucleophile takes place selectively at the central platinum(III) center, and the PPh2/OH- or PPh 2/N3 - reductive coupling yields the trinuclear [NBu4]2[(RF)2PtII(μ- Ph2PO)(μ-PPh2)PtII(μ-PPh 2)2PtII(RF)2] (6) and [NBu4][(RF)2Pt1(μ3- Ph2PNPPh2)(μ-PPh2)Pt2(μ- PPh2)Pt3(RF)2](Pt 2-Pt3) (7). Complex 7 is fluxional in solution, and an equilibrium consisting of Pt-Pt bond migration was ascertained by 31P EXSY experiments. © 2013 American Chemical Society.