Palladium PdCl2

Dichloro l,ll-[bis(diphenylphosphhie)]ferrocene palladium, PdCl2(dppf). 

Ding, Y., Fu, X. Theoretical study on the configuration of ethanol dichloro palladium [PdCl2(C2H40H)]. Chin. Chem. Lett. 1990, 1,183-184. 

IX OTHER MISCELLANEOUS REACTION CATALYZED BY PALLADIUM PdCl2(PhCN)2... 

Vinyl acetate reacts with the alkenyl triflate 65 at the /3-carbon to give the 1-acetoxy-1,3-diene 66[68]. However, the reaction of vinyl acetate with 5-iodo-pyrimidine affords 5-vinylpyrimidine with elimination of the acetoxy group[69]. Also stilbene (67) was obtained by the reaction of an excess of vinyl acetate with iodobenzene when interlamellar montmorillonite ethylsilyl-diphenylphosphine (L) palladium chloride was used as an active catalyst[70]. Commonly used PdCl2(Ph3P)2 does not give stilbene. 

The metallic palladium is reoxidized to PdCl2 by the CUCI2 and the resultant cuprous chloride is then reoxidized by oxygen or ait as shown. 

More recently, a commercial process has been introduced for the manufacture of methyl isocyanate (MIC) which involves the dehydrogenation of /V-m ethyl form am i de [123-39-7] in the presence of palladium, platinum [7440-06-4], or mthenium [7440-18-8], at temperatures between 50—300°C (31). Aprotic solvents, such as ben2ene [71-43-2], xylenes, or toluene [108-88-3], may optionally be used. A variation of this synthesis employs stoichiometric amounts of palladium chloride [7647-10-1], PdCl2. 

Synthesis. The most common staiting materials for palladium complexes are PdCl2 [7647-10-1] and [PdClJ [14349-67-8]. Commercially available materials useful for laboratory-scale synthesis iuclude [Pd2(OOCCH2)J [3375-31-3] [PdCl2(NCCgH )] [14220-64-5] [Pd(acac)2] [14024-61-4] [PdCl2(cod)] [12107-56-1], and [Pd(P(CgH5)3)J [14221-01-3]. 

The palladium chloride process for oxidizing olefins to aldehydes in aqueous solution (Wacker process) apparendy involves an intermediate anionic complex such as dichloro(ethylene)hydroxopalladate(II) or else a neutral aqua complex PdCl2 (CH2=CH2)(H2 0). The coordinated PdCl2 is reduced to Pd during the olefin oxidation and is reoxidized by the cupric—cuprous chloride couple, which in turn is reoxidized by oxygen, and the net reaction for any olefin (RCH=CH2) is then... 

CH2=C(OBn)CH2F, PdCl2(COD), CH3CN, it, 24 h, 89-100% yield. Protic acids can also be used to introduce this group, but the yields are sometimes lower. A primary alcohol can be protected in the presence of a secondary alcohol. This reagent also does not give cyclic acetals of 1,3-diols with palladium catalysis. 

Compared with these methods, the palladium-catalyzed oxidation of 1-olefins described here is more convenient and practical. The industrial method of ethylene oxidation to acetaldehyde using PdCl2-CuCl 2-O2 original reaction of this type. The oxidation of various olefins has been carried out. ... 

Use of DMF as a solvent for the oxidation of l-o1efins has been reported by Clement and Selwitz. The method requires only a catalytic amount of PdCl2 and gives satisfactory yields under mild conditions. A small amount of olefin migration product is the only noticeable contaminant in the cases reported. The procedure can be applied satisfactorily to various 1-olefins with other functional groups. This useful synthetic method for the preparation of methyl ketones has been applied extensively in the syntheses of natural products such as steroids,macrolides, dihydrojasmone, and muscone. " A comprehensive review article on the palladium-catalyzed oxidation of olefins has... 

Palladium and gold Palladium electrodeposition is of special interest for catalysis and for nanotechnology. It has been reported [49] that it can be deposited from basic chloroaluminate liquids, while in the acidic regime the low solubility of PdCl2 and passivation phenomena complicate the deposition. In our experience, however, thick Pd layers are difficult to obtain from basic chloroaluminates. With different melt compositions and special electrochemical techniques at temperatures up to 100 °C we succeeded in depositing mirror-bright and thick nanocrystalline palladium coatings [10]. 

The other palladium(II) halides are all diamagnetic. PdCl2 exists in well defined a- and /3-forms [16] (as well as a 7-form) the former has a PdCU/2... 

The important oxides are black PdO and brown Pt02. The former can be made by heating palladium in oxygen other methods include heating PdCl2 in an NaN03 melt at 520°C. A hydrated form precipitates from aqueous solution, e.g. when Pd(N03)2 solution is boiled. It has 4-coordinate square planar palladium (Figure 3.8). 

PdCl2(PPh3)2 and Cul in a mixture of Et2NH and DMF at 120 °C for 5-25 min were found to be suitable as a general protocol. For less reactive (hetero)aryl bromides and 2-chloropyridine, extra triphenylphosphine was added to improve the stability of the palladium catalyst (Scheme 49). 

Considerably less is known about the chemistry of palladium and platinum 1,1-dithio complexes. Of late, there has been only one report that dealt with the synthesis of a large number of palladium dithiocar-bamates 392). Twenty-five yellow palladium dithiocarbamate complexes were obtained by reaction of PdCla with NaR2dtc in methanol solution. Several other reports have appeared in which a few dithiocarbamate complexes of palladium were synthesized. Thus, the novel [Pd (OH)2dtc 2], which is soluble in water, was isolated 393). The synthesis of optically active palladium(II) complexes of AT-alkyl-a-phen-ethyldithiocarbamates, similar to (XXIV), via the reaction between the optically active amine, CS2, and PdCl2, has been described. From ORD and CD spectra, it has been established that the vicinal contribution of a remote, asymmetric carbon center could give rise to optical activity of the d—d transitions of palladium 394). Carbon disulfide has been shown to insert into the Pt-F bond of [PtF(PPh3)3]HF2, and X-ray studies indicated the structure (XXIX). 

Carbonyl-stabilized ylides and the cyano-stabiHzed ylides Ar3P=CHCN in spite of their low nucleophilicity are able to give stable complexes. By comparison, very few complexes involving the second category of ylides are known. However a new example has recently been described by reaction of the cyano-ylide 60 with palladium(II) to give the complex tra s-[PdCl2 CH(PTol3)CN 2] 61 (Scheme 24) [93]. 

PVP-PdCl2= palladium anchored on poly(N-vinyl-2-pyrrolidinone) Zhang, Y. Liao. S. Xu, Y. Tetrahedron Lett., 1994, 35, 4599... 

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