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

Abstract

The reaction of the neutral binuclear complexes [(R(F))(2)Pt(μ-PPh(2))(2)M(phen)] (phen = 1,10-phenanthroline, R(F) = C(6)F(5); M = Pt, 1; M = Pd, 2) with AgClO(4) or [Ag(OClO(3))(PPh(3))] affords the trinuclear complexes [AgPt(2)(μ-PPh(2))(2)(R(F))(2)(phen)(OClO(3))] (7a) or [AgPtM(μ-PPh(2))(2)(R(F))(2)(phen)(PPh(3))][ClO(4)] (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 [(R(F))(2)Pt(μ-PPh(2))(2)M(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 AgClO(4) or [Ag(OClO(3))(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))(PPh(3))], 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(OClO(3))(PPh(3))], forming a 1:1 mixture of [AgPdPt(μ-PPh(2))(2)(R(F))(2)(OClO(3))(dppm)] (11), in which the silver atom is connected to the Pt-Pd moiety through Pd-(μ-PPh(2))-Ag and Ag-P(k(1)-dppm) interactions, and [AgPdPt(μ-PPh(2))(2)(R(F))(2)(OClO(3))(PPh(3))(2)][ClO(4)] (12). The reaction of complex 4 with AgClO(4) 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-μPPh(2) bonds. When P-P is dppe, both complexes 5 and 6 react with AgClO(4) or [Ag(OClO(3))(PPh(3))], forming the saturated complexes [(PPh(2)C(6)F(5))(R(F))Pt(μ-PPh(2))(μ-OH)M(dppe)][ClO(4)] (M = Pt, 13; Pd, 14), which are the result of an oxidation followed by a PPh(2)/C(6)F(5) reductive coupling. Finally, the oxidation of trinuclear derivatives [(R(F))(2)Pt(II)(μ-PPh(2))(2)Pt(II)(μ-PPh(2))(2)Pt(II)L(2)] (L(2) = phen, 15; L = PPh(3), 16) by AgClO(4) results in the formation of the unsaturated 46 VEC complexes [(R(F))(2)Pt(III)(μ-PPh(2))(2)Pt(III)(μ-PPh(2))(2)Pt(II)L(2)][ClO(4)](2) (17 and 18, respectively) which display Pt(III)-Pt(III) bonds.

Donor Behaviour of Anionic and Asymmetric Phosphanido Derivatives of Platinum and Palladium

“…In the simplest cases, the dinuclear phosphanido complexes act as monodentate (Scheme 1, type A and B donors) or bidentate chelating (Scheme 1, type C) metal donor ligands towards the silver centre, and the final complexes display one or two M-Ag (M = Pt, Pd) bonds [36][37][38] for each dinuclear fragment. In a few other cases, a very unusual 3c-2e interaction between the M II -(μ-P) bond of the phosphanido complex and the Ag I centre is formed [38,39] (the dinuclear fragment acts as a type D donor, Scheme 1).…”

“…The Pt or Pd atoms are at the centres of square-planar coordination environments, which share an edge formed by the P atoms of the two phosphanide bridging ligands. [14,17,29,38,54] The silver centre of each complex completes its trigonal coordination environment with the phosphorus atom of the triphenylphosphane ligand. The other metal centre [Pt(2) in 1 and 3 or Pd in 4] is bonded to a planar bidentate C ∧ N (benzoquinolinate, 1) or O ∧ N (8-hydroxyquinolinate, 3 and 4) ligand coordinated in a chelate mode.…”

“…[38,[42][43][44] Finally, an example has been reported in which the L-LЈ ligand of [Ag 2 {Pt 2 (μ-PPh 2 ) 2 -(C 6 F 5 ) 2 (acac)} 2 ] (acac = acetylacetonate) acts as donor towards the silver atom (Scheme 1, type G and H). The XRD structures of 1-5, in which a [AgPPh 3 ] + moiety bridges the metal Eur.…”

“…[38,[42][43][44] Finally, an example has been reported in which the L-LЈ ligand of [Ag 2 {Pt 2 (μ-PPh 2 ) 2 -(C 6 F 5 ) 2 (acac)} 2 ] (acac = acetylacetonate) acts as donor towards the silver atom (Scheme 1, type G and H). [38,[42][43][44] Finally, an example has been reported in which the L-LЈ ligand of [Ag 2 {Pt 2 (μ-PPh 2 ) 2 -(C 6 F 5 ) 2 (acac)} 2 ] (acac = acetylacetonate) acts as donor towards the silver atom (Scheme 1, type G and H).…”

Reactivity of the phosphinito bridged Pt(i) complex [(PHCy2)Pt(μ-PCy2){κ2P,O-μ-P(O)Cy2}Pt(PHCy2)](Pt–Pt) towards Au(i) and Ag(i) electrophiles

“…The reaction of coinage metal based electrophiles with transition metal complexes has long been used for the synthesis of small-size clusters. 7 As far as the reaction of group 11 electrophiles with platinum phosphanido bridged complexes is concerned, most cases deal with platinum(II) compounds and result in (i) the oxidation of the metal [from Pt(II) to Pt(III)] [8][9][10][11] or of the phosphorus ligands; 12,13 (ii) the formation of adducts in which M + bridges two Pt atoms; 11,14 (iii) the formation of adducts in which M + bridges the Pt-μ-P bond; 11,15 (iv) the formation of adducts displaying a single M-Pt bond; 11 (v) halide abstraction. [16][17][18] The reported examples of reactions of Pt(I) dimers with group 11 electrophiles comprise coordination of an [Au(PPh 3 )] + fragment at a Pt-μ-P bond 19 as well as coordination of the electrophile at the Pt-Pt bond.…”