Potassium tetrachloropalladate

Potassium tetrachloropalladate(II) reacts with 1 to give CH3C1 and metallic Pd as products (48). This reaction apparently follows the same mechanism as the Hg(II) system, with reported rate constants K (= kj A 4) = 150 and k2 = 7.7 x 10 3 M sec-1. Additional support for the proposed methylpalladium(II) intermediate comes from the report of such a species, detected by proton NMR spectroscopy, in the reaction of PdCir with (CH3)3Sn+ (44). There has been a separate study on the base-off complex formed between PdCl4 and 1 (49). Attempts to react K2PdCl6 with 1 proved futile, due to the extremely rapid decomposition of the Pd salt under reaction conditions (46). 

A mixture of potassium tetrachloropalladate(II) (3.26 g., 10.0 mmoles), water (125 ml.), and 1,5-cyclooctadiene (2.0 ml.) is shaken vigorously for 15 minutes, during which time a yellow solid forms. This is filtered, washed with water (three times with 30 ml.), and dried in vacuo overnight to give dichloro-(l,5-cyclooctadiene)palladium(II) (2.6 ) g.). 

Five grams (0.0153 mole) potassium tetrachloropalladate(II) is dissolved in 40 ml. of warm water, and the resulting solution is divided into two equal portions. To one of the portions in a 125-ml. Erlenmeyer flask is added 10.5 ml. (0.0158 mole) of 1.50 M ethylenediamine. The ethylenediamine should be... 

The reagents can be prepared by heating potassium tetrachloropalladate (K2PdCl4) with an excess of the potassium halide and an excess of triphenyl-phosphine in ethanol. They can be crystallized from chloroform. 

A novel insoluble green complex of palladium(II) and N,N -salicylideneethylenedi-amine (salen) functions as a selective heterogeneous catalyst, notably for the reduction of alkynes in the presence of alkenes, and of the latter in the presence of certain functional groups. E ciVEthylene from acetylene derivs. A soln. of startg. acetylene deriv. in EtOH hydrogenated for 17 min in the presence of the palladium(ll) complex (prepared from potassium tetrachloropalladate, salen, and triethylamine) cis-product. Y 100%. Reduction of alkenes is considerably slower however, terminal olefins may be reduced in the presence of internal olefins esters, oxo compds., dibenzyl ether, and iodobenzene were unaffected. F.e., also ar. amines from nitro compds. s. J.M. Kerr et al.. Tetrahedron Letters 29, 5545-48 (1988). 

Form Supplied in pale yellow crystals widely available. Analysis of Reagent Purity IR MS NMR H NMR. Preparative Methods numerous routes are available. Preferred methods are reaction of propene with palladium(II) trifluoro-acetate, followed by counterion exchange with chloride reaction of potassium tetrachloropalladate(II) with allyl chloride in water reaction of Na2PdCl4, allyl chloride, and CO in water. ... 

The palladium(ii) acetylacetonate-tri phenyl phosphine catalysed reaction of butadiene with water and carbon dioxide in solvents such as t-butanol or acetone has been reported to give octa-2,7-dien-l-ol as the major product together with minor amounts of octa-l,7-dien-3-ol, 1,3,7-octatriene and octadienyl ethers. In contrast aqueous potassium tetrachloropalladate with excess diene leads to pale yellow solids which were polymeric. Decomposition of these complexes with dimethylglyoxime gave a mixture of 3-methyIbutenyl ethers, (Scheme 33). The use of (—)-2,2-dimethyl-4,5-bis(diphenylphosphinomethyl)-l,3-dioxolane (DIOP) as a chiral ligand... 

A concentrated solution of potassium tetrachloropalladate(II), K2[PdCl4] (0.330 g, 0.001 mol), is prepared by dissolving it in a minimum amount ( 2.5mL) of water at room temperature. A methanol (3mL) solution of triethyl phosphite (0.831 g, 0.005 mol) is placed in a test tube containing a small stirring bar. The triethyl phosphite (Matheson, Coleman and Bell) was distilled before use and kept under nitrogen (bp 77°, 25 mm). 

One organic group is readily transferred from tetraorganosilanes (and some other silanes) to palladium ). Tetramethylsilane, lithium tetrachloropalladate(II) and styrene at 120 C in acetonitrile solution form 1 -phenyl- 1-propene in 65% yield along with ca. 1.5% 2-phenyl-1-propene.33 Trimethylphenylsil-ane transfers phenyl and with styrene under the above conditions gives fra/w-stilbene in 94% yield.33 Similar vinyl substitution reactions have been achieved with potassium ( )-alkenyl pentafluorosili-cates.34... 

Tetraamminepalladium(II) tetrachloropalladate(II), the palladium analog of Magnus green salt, [Pt(NH3)4][PtCl4], may be prepared by treatment of aqueous ammonium tetra-chloropalladate(II) with aqueous ammonia, by addition of aqueous ammonia to a palladium(II) chloride solution, by treatment of aqueous tetraamminepalladium(II) chloride with palladium(II) chloride solution, and by precipitation on mixing a freshly prepared solution of a tetra-amminepalladium(II) salt with cold aqueous potassium tet-... 

Five grams of palladium(II) chloride [or 8 g. of ammonium tetrachloropalladate(II)] is dissolved in about 350 ml. of warm water to which a few drops of hydrochloric acid has been added. To the well-stirred solution is added dropwise a solution of 3.7 g. of potassium cyanide in about 50 ml. of water. As yellow palladium(II) cyanide precipitates, the supernatant liquid becomes colorless. The gelatinous precipitate is filtered on a Buchner funnel, washed well with water, transferred to a beaker, and dissolved in a solution of 4 g. of potassimn cyanide in about 75 ml. of water. Heat and agitation aid the solution process. The liquid is filtered and evaporated on a hot plate imtil crystals begin to form. When the solution has cooled, the crystals are filtered on a small Bttchner funnel and washed with a few drops of cold water. The process of evaporation, cooling, and filtering off the crystals formed may be repeated once or twice with the mother liquor. The salt may be purified by recrystallization from water ... 

The or//io-palladation of 3,4-dioxygenated benzylic tertiary amines by lithium tetrachloropalladate can be directed exclusively to either C-2 or C-6. Substitution at C-6 prevails when AcO, methylenedioxy, PhCH20, methoxymethyl ether, or HO substituents are attached to C-3, whereas palladation occurs exclusively at C-2 when C-3 bears methylthiomethyl ether or phenylthiomethyl ether substituents. The resulting organopalladium compounds are crystalline solids, stable to air and moisture, and can readily be carbonylated, alkylated, arylated, Kinetic studies of the acetoxylation of arenes by potassium peroxydisulphate and acetic acid in the presence of (2,2 -bipyridyl)palladium(ii) acetate catalyst have led to a revision of the mechanism. The reaction is now thought to proceed via... 

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