Behavior of Neutral Phosphido Derivatives of Platinum and Palladium toward Silver Centers

Abstract

The reaction of the neutral binuclear complexes [(RF) 2Pt(μ-PPh2)2M(phen)] (phen = 1,10-phenanthroline, RF = C6F5; M = Pt, 1; M = Pd, 2) with AgClO4 or [Ag(OClO3)(PPh3)] affords the trinuclear complexes [AgPt2(μ-PPh2) 2(RF)2(phen)(OClO3)] (7a) or [AgPtM(μ-PPh2)2(RF)2(phen) (PPh3)][ClO4] (M = Pt, 8; M = Pd, 9), which display an >open-book> type structure and two (7a) or one (8, 9) Pt-Ag bonds. The neutral diphosphine complexes [(RF)2Pt(μ-PPh 2)2M(P-P)] (P-P = 1,2-bis(diphenylphosphino)methane, dppm, M = Pt, 3; M = Pd, 4; P-P = 1,2-bis(diphenylphosphino)ethane, dppe, M = Pt, 5; M = Pd, 6) react with AgClO4 or [Ag(OClO3)(PPh 3)], and the nature of the resulting complexes is dependent on both M and the diphosphine. The dppm Pt-Pt complex 3 reacts with [Ag(OClO 3)(PPh3)], affording a silver adduct 10 in which the Ag atom interacts with the Pt atoms, while the dppm Pt-Pd complex 4 reacts with [Ag(OClO3)(PPh3)], forming a 1:1 mixture of [AgPdPt(μ-PPh2)2(RF)2(OClO 3)(dppm)] (11), in which the silver atom is connected to the Pt-Pd moiety through Pd-(μ-PPh2)-Ag and Ag-P(k1-dppm) interactions, and [AgPdPt(μ-PPh2)2(RF) 2(OClO3)(PPh3)2][ClO4] (12). The reaction of complex 4 with AgClO4 gives the trinuclear derivative 11 as the only product. Complex 11 shows a dynamic process in solution in which the silver atom interacts alternatively with both Pd-μPPh2 bonds. When P-P is dppe, both complexes 5 and 6 react with AgClO4 or [Ag(OClO3)(PPh3)], forming the saturated complexes [(PPh2C6F5)(R F)Pt(μ-PPh2)(μ-OH)M(dppe)][ClO4] (M = Pt, 13; Pd, 14), which are the result of an oxidation followed by a PPh 2/C6F5 reductive coupling. Finally, the oxidation of trinuclear derivatives [(RF)2Pt II(μ-PPh2)2PtII(μ-PPh 2)2PtIIL2] (L2 = phen, 15; L = PPh3, 16) by AgClO4 results in the formation of the unsaturated 46 VEC complexes [(RF)2Pt III(μ-PPh2)2PtIII(μ-PPh 2)2PtIIL2][ClO4] 2 (17 and 18, respectively) which display Pt(III)-Pt(III) bonds. © 2011 American Chemical Society.