An unexpected entry into the silver(I) chemistry of diphosphazane ligands: crystal and molecular structures of [Ag{Ph₂PN(Prⁱ)PPh₂}(CF₃SO₃)]₂, [Ag{Ph₂PN(Prⁱ)PPh(OC₆H₃Me₂-2,6)}₂]PF₆, and [Ag₃(μ-Cl)₂{Ph₂PN(R)PPh₂}₃]PF₆ (R = H, Prⁱ)

Abstract

Mononuclear, binuclear and trinuclear silver(I) complexes were obtained unexpectedly while probing the reactivity of diphosphazane ligands of the type X₂PN(Prⁱ)PXY towards the ruthenium-based precursor Ru(bipy)₂Cl₂ · 2H₂O, in the presence of a silver salt as a chloride scavenger. Subsequently, the reactions of AgX [X = Cl, NO₃ or CF₃SO₃] with Ph₂PN(R)PPh(Y) [R = H, Y = Ph; R = Prⁱ, Y = Ph or OC₆H₃Me₂-2, 6] in a 1:1 or 1:2 molar ratio have been investigated. Mononuclear or binuclear Ag(I) complexes containing either chelating or bridging diphosphazane ligands are obtained. Trinuclear silver(I) complexes are accessible by the treatment of diphosphazane ligands, Ph₂PN(R)PPh₂ [R = H, Prⁱ] with AgCl using piperidine as the solvent. In the presence of a suitable chloride donor species, the mononuclear and binuclear complexes of Ph₂PN(Prⁱ)PPh₂ are transformed slowly to the trinuclear complex [Ag₃(μ-Cl)₂{Ph₂PN(Prⁱ)PPh₂} ₃]X, over a period 20 h. The structures of representative complexes have been confirmed by X-ray crystallography and the salient structural features are discussed.