Half-sandwich cyclopentadienyl ruthenium complexes of achiral and chiral diphosphazanes

Abstract

Reaction of [CpRu(PPh₃)₂Cl] (1) {Cp = η⁵-(C₅H₅)} with X₂PN(CHMe₂)PYY′ {X = Y = Y′ = Ph (L¹); X = Y = Ph, Y′ = OC₆H₄Me-4 (L⁴); X = Y = Ph, Y′ = OC₆H₃Me₂-3,5 (L⁵); X = Y = Ph, Y′ = N₂C₃HMe₂ (L⁶)} yields the cationic chelate complexes, [CpRu(η²-(X₂PN(CHMe₂)PYY′))PPh₃]Cl. On the other hand, the reaction of 1 with X₂PN(CHMe₂)PYY′ {X₂ = YY′ = O₂C₆H₄(L²)} gives the complex, [CpRu(η¹-L²)₂PPh₃]Cl. Both types of complexes are formed with X₂PN(CHMe₂)PYY′ {X = Ph, YY′ = O₂C₆H₄ (L³)}. The reaction of 1 with (R),(S)-(H₁₂C₂₀O₂)PN(CHMe₂)PPh₂ (L⁷) yields both cationic and neutral complexes, [CpRu{η²-(L⁷)}PPh₃]Cl and [CpRu{η¹-(L⁷)}₂PPh₃]Cl and [CpRu{η²-(L⁷)}Cl]. The reactions of optically pure diphosphazane, Ph₂PN(*CHMePh)PPhY (Y = Ph (L⁸); Y = N₂C₃HMe₂-3,5 (L⁹)) with 1 give the neutral and cationic ruthenium complexes, [CpRu{η²-(Ph₂PN(R)PPhY)}Cl] and [CpRu{η²-(Ph₂PN(R)PPhY)}PPh₃]Cl. “Chiral-at-metal” ruthenium complexes of diphosphazanes have been synthesized with high diastereoselectivity. The absolute configuration of a novel ruthenium complex, (S_CS_PR_Ru)-[(η⁵-C₅H₅)Ru*{η²-(Ph₂PN(*CHMePh)P*Ph(N₂C₃HMe₂-3,5))}Cl] possessing three chiral centers, is established by X-ray crystallography. The reactions of [CpRu{η²-(L⁸)}Cl] with mono or diphosphanes in the presence of NH₄PF₆ yield the cationic complexes, [CpRu{η²-(L⁸)}{η¹-(P)}]PF₆ {P = P(OMe)₃, PPh₃, Ph₂P(CH₂)_nPPh₂ (n = 1 or 2)}.