Palladium dichloride

Palladium(V) complexes, 5, 1100 Palladium compounds photothermography, 6, 118 Palladium dichloride solid state oligomerization, 1, 187 Palladium(II) salts sensitizers... 

Tetrakis(tripheiiylphosphine)palladium(0) is often used for this reaction. However, Pd(II) complexes such as bis(triphenylphosphine)palladium dichloride or palladium acetate are also commonly employed for convenience, as they are stable in ah. The base is typically a secondary or tertiary amine such as triethy-lamine. Weak bases such as sodium (potassium) acetate, bicarbonate, or carbonate are also used. 

Harada M, Asakura K, Toshima N (1993) Catalytic activity and structural analysis of polymer-protected gold/palladium bimetallic clusters prepared by the successive reduction of hydrogen tetrachloroaurate(ffl) and palladium dichloride. J Phys Chem 97 5103-5114... 

One of palladiums unique characteristics is its abihty to absorb 900 times its own volume of hydrogen gas. When the surface of the pure metal is exposed to hydrogen gas (H ), the gas molecules break into atomic hydrogen. These hydrogen atoms then seep into the holes in the crystal structure of the metal. The result is a metallic hydride (PdH that changes palladium from an electrical conductor to a semiconductor. The compound palladium dichloride (PdCl ) also has the ability to absorb large quantities of carbon monoxide (CO). These characteristics are useful for many commercial applications. Palladium is the most reactive of all the platinum family of elements (Ru, Rh, Pd, Os, Is, and Pt.)... 

Mizugaki et al. 74) have recently utilized thermomorphic properties of Pd(0)-complexed phosphinated dendrimers for dendritic catalyst recycling. Using the method developed by Reetz 16), they prepared dendritic ligands containing, respectively, 2, 8, 16, and 32 chelating diphosphines. Palladium dichloride was com-plexed to the dendrimers, and a reduction in the presence of triphenylphosphine gave the Pd(0)-complexed dendrimers (80—83). The dendritic complexes were active... 

Palladium dichloride is a starting material for preparing several palladium compounds. It also is used for detection of carbon monoxide. For such detection, a paper is soaked in very dilute solution of PdCb which is decolorized by CO, methane and other reducing substances. It also is used in toning and electroplating solutions and in photography for porcelain pictures. 

Palladium dichloride is prepared by dissolving palladium metal in aqua regia or hydrochloric acid in the presence of chlorine. Alternatively, it may be prepared by heating palladium sponge with chlorine gas at 500°C... 

Palladium dichloride forms polymeric carhonyl complexes when the dry chloride is heated in a stream of carhon monoxide charged with methane vapor. Such complexes include [PdCl2(CO)n] and [PdCl(CO)2]n. The reaction also occurs in aqueous phase resulting in decolorization of the solution. 

When H2S is passed through palladium dichloride solution, it yields a brown-black precipitate of palladium monosulfide, PdS. 

When heated with sulfur at 450 to 500°C, palladium dichloride forms palladium disulfide, PdS2, a grey-black crystalline compound, insoluble in strong acids but soluble in aqua regia, and which converts to monosulfide, PdS, on heating at 600°C. 

Both pyrimidine and quinazoline derivatives have been investigated as ligands for palladium-mediated reactions. Examples of ligands prepared include the phosphine-free bipyrimidine 1181, which gave the isolable palladium dichloride catalyst 1182 <2001JOM(634)39>, and the chiral oxazolinyl-quinazoline BINAP analogs 1183 and 1184 <20060L5109>. 

Die in situ hergestellten Trifluormethansulfonsaure-Salze von 5-Amino-1-penten, 6-Amino-l-hexen und einigen ihrer Derivate werden in Gegenwart von Bis-[benzonitril]-palladium-dichlorid in Tetrahydrofuran cyclisiert, z. B. zu 2-Methyl-pyrrolidin (65%), l-Isopropyl-2-methyl-pyrrolidin (78%), 2,4,4-Trimethyl-pvr-rolidin (73%) und 2-Melhyl-piperidin (76%). ... 

Die Uberfiihrung von Alkenen in vie.-Diamino-alkane gelingt in mittleren Ausbeuten in einer Eintopfreaktion durch Umsetzung des Alkens mit 0,5 mol-Aquivalenten Bis-[ben-zonitrilj-palladium-dichlorid in Tetrahydrofuran bei 0°, Zugabe eines Uberschusses von sekundarem Amin und Oxidation des so gebildeten Aminoalkyl-palladium-Komplexes... 

Die Umsetzung von aktivierten Ethenen (z. B. Butenon, Acrylsaure-ester, Acrylnitril) mit N-Methyl-anilin oder 2-Brom-anilin und 1,4-Benzoehinon in Tetrahydrofuran in Gegen-wart von Lithiumchlorid und 0,1 Mol-Aquivalenten Bis-[acetonitril]-palladium-dichlorid fiihrt zur Aminierung der Methylen-Gruppe der Ethen-Derivate2. 

A similar approach was taken for the synthesis of 45 by Miyaura. " Shaughnessy and Booth synthesized the water-soluble alkylphosphine 46, and found it to provide very active palladium catalysts for the reaction of aryl bromides or chlorides with boronic acids. The more sterically demanding ligand 47 was shown to promote the reactions of aryl chlorides with better results than 46. Najera and co-workers recently reported on the synthesis of di(2-pyridyl)-methylamine-palladium dichloride complexes 48a and 48b, and their use in the coupling of a variety of electrophiles (aryl bromides or chlorides, allyl chlorides, acetates or carbonates) with alkyl- or arylboronic acids very low catalyst loadings at Palladium-oxime catalysts 8a and 8b) have also been developed. In conjunction with... 

A reaction vessel was charged with the step 3 product (1.77 mmol), bis(pinacolate)-diborone (3.72 mmol), [1,1 -bis(diphcnyl-phosphino)-ferroccnc]palladium dichloride (0.11 mmol), l,l -bis(diphenylphosphino)ferrocene (0.11 mmol), and 15 ml of... 

An alternative approach to form a cyclobutylmethyl cation from a vinylcyclobutane uses organopalladium chemistry.25 For example, exposure of l-methyl-7-vinylbicyclo[4.2.0]octan-7-ol to 5mol% of bis(benzonitrile)palladium dichloride and 1,4-benzoquinone in boiling tetrahydrofuran gave the desired 6,9-dimcthylbicyclo[4.3.0]non-l(9)-en-8-one (7) in 67% yield.25 The mechanistic pathway of this transformation is shown. Further examples, showing the utility of the reaction, are shown for the rearrangement to 8.23... 

The formation of some silylated i73-allylic complexes has been, however, achieved by reacting substituted silyl olefins with bis(benzonitrile)palladium dichloride. The mechanism is rather complex and two olefin molecules are incorporated in the final i -allylic ligand 169) ... 

The ring closure of aminoalkynes bearing a leaving group in the appropriate position might lead to the formation of pyrroles in an addition-elimination sequence. 2-Phcnylcthynyl-1 -amino-sec-butanol. for example, gave 4-ethyl-2-phenylpyrrole on treatment with palladium dichloride in acetonitrile in excellent yield (3.46.),57... 

The coupling of thiophene derivatives, particularly thiopheneboronic acids, is frequently employed in medicinal chemistry and also in materials science. In a recent example 2-thiopheneboronic acid was coupled with a triazolopyridine derivative (6.4.) in the presence of [1,1-bis(diphenylphosphino)ferrocenyl]palladium dichloride in 83% yield6... 

Thienylstannanes were also coupled with a series of reagents other, than conventional aryl halides. 2,2 -Bithiophene was prepared from the thienyliodonium salt shown in 6.34. and 2-tributylstannylthiophene. The activity of the iodonium salt allows for the room temperature coupling of the reagents in the presence of only 0.5 mol% palladium dichloride in a coordinating solvent mixture to give an excellent yield of the desired product.48... 

An alternate approach to the palladium catalyzed ethynylation of thiophene derivatives has been reported by Zeni and co-workers. They coupled 2-(butyltelluro)thiophenes with different acetylenes (6.48.), The reaction, which was effectively catalyzed by palladium dichloride, was run in the absence of copper salts. The choice of base (triethylamine) and solvent (methanol) were both crucial for the success of the coupling.70... 

The introduction of a masked uracil moiety onto the pyridine core was achieved in the reaction of 3-tributylstannylpyridine with 5-bromo-2,4-bis(trimethylsilyloxy)pyrimidine (7.26.) The coupling proceeded in the presence of bis(triphenylphosphine)palladium dichloride to give the desired product in 42% yield (c.f 7.13.),37... 

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