New studies on the reactivity of allyl difluorophosphate palladium complexes: synthesis of the first difluorophosphate metallocene derivatives

Abstract

The reaction of [Pd(η 3-2Me-C 3H 4)(μ-PO 2F 2)] 3 1, previously synthesized by us, with P- or S-donor ligands leads to the new derivatives [Pd(η 3-2Me-C 3H 4)(PO 2F 2)L] (L=PMePh 2; P(OR) 3, R=Me, Et, Ph; SPPh 3) and [Pd(η 3-2Me-C 3H 4)L 2]PO 2F 2 (L=SPPh 3). The neutral and ionic derivatives with L=tetrahydrothiophene, were detected by 1H-NMR. The fluxional behavior of SPPh 3 complexes has been analyzed and a dissociation of SPPh 3 ligand evidenced. When 1 is made to react with M(η 5-C 5R 5) 2Cl 2 (M=Ti, R=H, Me; M=Mo, R=H) the new metallocene derivatives M(η 5-C 5R 5) 2(PO 2F 2) 2 are obtained. Using M(PPh 3)PF 6 (M=Ag, Cu) the complex [Pd(η 3-2Me-C 3H 4)(PPh 3) 2]PF 6 and M(PO 2F 2) x (M=Ag, x=1; M=Cu; x=2) are formed. A similar reaction takes place between [Pd(η 3-2Me-C 3H 4)(PO 2F 2)(PPh 3)] and Ag(ClO 4)PPh 3. With AuPPh 3PF 6 and 1 no reaction is observed. The derivatives trans-[PdCl(μ-Cl)(PR 3)] 2 (R=Ph, Cy) and [Pd(η 3-2Me-C 3H 4)(PhCN) 2]PO 2F 2 are formed after the reaction of [Pd(η 3-2Me-C 3H 4)(PO 2F 2)(PR 3)] and PdCl 2(PhCN) 2. 1 or [Pd(η 3-2Me-C 3H 4)(PO 2F 2)(PPh 3)], 2, does not react with weak acids However, HCl gives rise to [Pd(η 3-2Me-C 3H 4)Cl(PPh 3)] after the reaction with 2. HBF 4 also reacts with 1 or 2 and by means of 19F-NMR studies at low temperatures BF 4 − coordination has been observed when a non-coordinating solvent is used.