Palladium(II) Complexes with 1,1‘−Bis(diphenylphosphino)ferrocenes [Fe(η⁵-C₅R₄PPh₂)₂]ⁿ⁺(dppf, R = H,n= 0; dppomf, R = Me,n= 0; dppomf⁺, R = Me,n= 1). Synthesis, Characterization, and Catalytic Activity in Ethene Methoxycarbonylation

Abstract

Several palladium(II) complexes with 1,1‘-bis(diphenylphosphino)octamethylferrocene (dppomf) and its oxidized form 1,1‘-bis(diphenylphosphino)octamethylferrocenium (dppomf+) have been synthesized and characterized by spectroscopic and electrochemical methods. For comparative purposes, analogous Pd(II) derivatives with 1,1‘-bis(diphenylphosphino)ferrocene (dppf) have been also prepared. Single-crystal X-ray analyses have been carried out for the square-planar mononuclear compounds [Pd(H2O)2(dppf)](OTf)2 and [Pd(H2O)2(dppomf)](OTf)2 and for the binuclear complex [Pd(μ-OPF2O)(dppomf+)]2(BF4)4·6CH2Cl2 in which two [Pd(dppomf+)]3+ moieties are held together by the oxygen atoms of two bridging PO2F2 - groups derived from the oxidative degradation of PF6 - ions. Selected dppf and dppomf Pd(II) complexes have been employed as catalyst precursors for the methoxycarbonylation of ethene (600 psi, 1:1 CO/C2H4, 85 °C). It has been found that dppomf generates selective catalysts for the production of methyl propanoate, while dppf leads to a variety of low-molecular-weight oxygenates spanning from methyl propanoate to alternating oligoketones.

Methoxycarbonylation of Styrene Catalyzed by Palladium Complexes with Ferrocene Derivatives Containing Nitrogen and Phosphine Ligands

“…The [Pd(dppf)PPh 3 ](BF 4 ) 2 and Pd(dppf)Cl 2 complexes showed the best conversion (black line and green lines, Graph 1), close to 100% in times no longer than 12 h. The chemoselectivity shown by this type of catalyst is similar to that reported by other authors [9,25,30].…”

“…Palladium chloride, p-CH 3 C 6 H 4 SO 3 HÁ H 2 O, PPh 3 , PCy 3 , and styrene were purchased from Aldrich. The Pd(dppf)Cl 2 [30], [Pd(dppf)(MeCN) 2 ](BF 4 ) 2 [30], [Pd(dppf)PPh 3 ](BF 4 ) 2 [30], Pd(PCy 3 ) 2 Cl 2 [31], Pd(PPh 3 ) 2 Cl 2 [31], and Pd(MeCN) 2 Cl 2 [32] complexes were prepared according to methods reported in the literature.…”

Synthesis, characterization and catalytic activity in the carbonylation of ethene of cis-[Pd(H2O)2(PPh3)2]X2·nH2O (X=p-CH3C6H4SO3, n=2; X=CH3SO3, n=0). X-ray structure of cis-Pd(H2O)2(PPh3)2](p-CH3C6H4SO3)2·2H2O and of cis-[Pd(H2O)2(PPh3)2](CH3SO3)2·2CH2Cl2

“…In the complex described in this work, the P(1)-Pd-P(2) angle measures 97.6(1)°. This is the third largest value recorded so far for aqua cis-diphosphine palladium(II) derivatives and is also slightly larger than that found in the almost equal [Pd(H 2 [41] (96.4(1)°). In Ia, it measures 87.4(1)°and agrees well with the values reported for the other diaqua complexes.…”

“…Ellipsoids have been drawn at the 40% probability level. Table 3 Selected bond distances ( A) and bond angles (°) for Ia and IIa AE 2CH 2 Cl 2 the Cambridge Structural Database, we could find only six monoaqua and five diaqua-cis-diphosphine palladium(II) derivatives [24,29,[38][39][40][41][42]. In all these structures but one [29] the phosphorous atom belongs to a chelate diphosphine ligand.…”

Phosphine Ligands in the Palladium‐Catalysed Methoxycarbonylation of Ethene: Insights into the Catalytic Cycle through an HP NMR Spectroscopic Study

“…BH 3 (27) gave the boron-protected bidentate phosphine ligands [23][24][25][26]. [61,62] Deboronation of the phosphines 23-26 was achieved by the addition of an excess of tetrafluoroboric acid to give an in situ prepared phosphonium salt that was then reduced to the desired phosphine by the addition of potassium hydroxide.…”