With 02, PdCl

Among these in situ protocols are those using ionic liquids as the solvent, or as both the solvent and the ligand. It was shown that the use of PdCOAc) in imidazolium-based ionic liquids forms in situ NHC-Pd(II) species [42], The use of methylene-bridged bis-imidazolium salt ionic liquids to form chelated complexes has also been reported [43], although better results have been obtained when Bu NBr is used as the solvent [44] and imidazolium salts were added together with PdCl in catalytic amounts [45]. Other related catalytic species such as bis-NHC complexes of silica-hybrid materials have been tested as recyclable catalysts [46,47]. 

The yield of 1 1 adduct rose to about 85% if the reaction was carried out at about 100°C with [PdCl-ir-C3H5]2 as the catalyst. 

TEAA = tetraethylammonimn acetate LDH-OsW = layered double hydroxides [Mgi Al t(OH)2(Cl) zH20] with OsOa and ions LDH-PdOsW = layered double hydroxides [Mgj Al t(OH)2(Cl)2 zHrO] with PdCl, ", OsOa " and WOa ions (DHQD)2PHAL = 1,4-bis(9-0-dihydroquinidinyl)phthalazine. 

Carbonylation of 1,3-dienfes with PdCL gives / ,y-unsaturated esters (9, 10, 11, 12). Butadiene is carboalkoxylated catalytically to form ethyl 3-pentenoate with either PdCl2 and ethanol (9, 10) or with (Ph3P)2PdCl2 in ethanol containing 10% HC1 (8). Tsuji and Ohno (13) propose a mechanism with butadiene that involves the conversion of a PdCl-butenyl... 

Deprotonation of the cyclopentadiene in 3 with KO Bu in THF afforded an anion, [K(THF)n][C60Me5(CN)Ph5], which reacted with [PdCl(at-allyl)]2 to give a pal-... 

Lee et al. [242] showed that the paUadium(II) complex can be synthesised via the silver(I) oxide route with carbene transfer or directly with PdCl in the presence of a base. Abstraction of chloride with AgBF results in the formation of the corresponding dicationic complex after uptake of a ligating solvent molecule. 

Reaction of the same functionalised imidazolium salt with PdCl produced interesting results [123], In the presence of pyridine as base, the simple palladium(ll) carbene adduct was formed (see Figure 4.42), but when K COj was used as base, activation of the amide functional groups produced the corresponding homoleptic complexes, as a mixture of the cis and trans isomers. 

The reaction of the zirconocene imido complex 800 with PdCl(Me)(COD) gives Zr/Pd heterobimetallic complexes 801 with bridging alkylideneamido ligands613 (Scheme 200). The molecular structures of the complexes 801 have puckered ZrN2Pd rings with Zr-Pd distances of 2.8135(5) A (Ar = Ph) and 2.8416(4) A (Ar =/>-tolyl), respectively. Upon treatment with HX (X = Cl, OPh), complexes 801 are converted to Cp2ZrX2 and //77/7i--PdCl(Me)(NH=GAr2)2. 

Figures 7.6a and b show high resolution SEM images of the Co-Zr-Nb SUL surface without any treatment and that treated with PdCl solution, respectively. An island-like stmcture with the mean diameter of ca. 9 nm was formed on the SUL with a high density, where the mean distance between adjacent clusters was ca. 18 nm. From X-ray photospectroscopy and diffractometry, the island-like structure was identified as the Pd metal with fee stmcture [30], which is hereafter called Pd cluster seeds .

Fig. 7.6 SEM images of (a) Co-Zr-Nb soft magnetic underlayer surface without any treatment and (b) that treated with PdCl solution [31]...

Fig. 15.11 (a) Pd 3d5/2 region of the XPS spectrum of an APTES coated oxide Si wafer (b) an APTES coated oxide Si wafer treated with PdCl, solution (c) wafer from part (b) after treatment with DMAB solution... 

Fig. 15.12 (a) TEM image of APTES coated C grid treated with standard PdCl solution following reduction process (b) APTES coated C grid treated with PdCl solution containing 1.0 mol dm of Cl ions following reduction process... 

Many alkenes will react with PdCL, forming a tt-allyl complex and one mole of HCl. A base is normally added to react with the HCl produced. Solvents that have proven useful include acetic acid, chloroform, methanol, and DMF. Where isomeric itt-allyl palladium complexes can be formed, one often obtains a mixture of products. This is particularly true for reactions run in acetic acid. The addition of CuCL causes an increase in regioselectivity, resulting in abstraction of the allylic C-H bond that leads to the more-substituted tt-allyl complex (equation 53). 

A similar support was used to prepare a bidentate analog of The support was treated with [PdCl(7] -C3Hs)]2... 

Iti-Dienes. Treatment of vinylmercurials, prepared from alkynes as shown, with PdCls in benzene leads to unsymmetrical coupled 1,3-dienes. The yield is improved dramatically with added triethylamine. An example is formulated in equation... 

A new tetrapodal phosphine ligand, ds,ds,ds-l,2,3,4-tetrakis(diphenylphosphino-methyl)cyclopentane (Tedicyp), in association with [PdCl(C3H5)]2, is an extremely efficient catalyst for allylic amination [20]. Addition of diisopropylamine to an allyl acetate [Eq. (3)] is suprisingly higher in water than in THF. 

Asymmetric 1,4-hydrosilylation of 1,3-dienes is an important method for the synthesis of enantio-enriched allylsilanes, which are used in organic synthesis as chiral allylation agents. [ PdCl( f-C3H5) 2] combined with modified MOP ligand (Fig. 15) permits enantioselectivities of up to 91% in asymmetric hydrosilylation of 1,3-cyclopentadiene and up to 79% while linear dienes are used. Bis(ferrocenyl)monophosphine (Fig. 16) used in combination with [ PdCl( f-C3H5) 2] enabled enantioselectivities up to 93% ee in asymmetric 1,4-hydrosilylation of linear 1,3-dienes with HSiCU. 

In a handful of cases, two CCXIH groups have been activated for the synthesis of biaryls. Larrosa and coworkers reported for the first time the decarboxylative homocoupling of aromatic acids mediated by Pd and Ag [62a]. The reaction makes use of Pd(TFA)j as a catalyst and Ag CO as an additive to afford the desired biaryls in 76-95% yields. The only by-products observed were due to the proto-decarboxylation of the aryl carboxylic acid. Both metals are essential for the reaction, and the role of the Ag salt is not only as the terminal oxidant but also as a mediator of the decarboxylation process. The method is subject to some limitations on the substituents on the benzoic acids. Thus, m- and p-nitrobenzoic acids as well as benzoic acids ortho substituted with F, Br, or MeO failed to give decarboxylative homocoupling products. In all cases, protodecarboxylations to the corresponding arenes were the main products observed. The same problem was reported in the protocol developed by Deng and coworkers, where the best results were obtained with PdCl and PPhj in the presence of Ag COj [62b]. 

Liang B, Dai M et al (2005) Copper-free Sonogashira coupling reaction with PdCl in water under aerobic conditions. J Org Chem 70 391-393... 

A detailed study on reaction 23 has been later reported [86]. Many different rhodium complexes were examined as catalysts and the effect of phosphine and phosphite ligands was investigated. Moreover, a binary catalyst, obtained by mixing RhCl(PPh3)3 with PdCL, showed high activity and selectivity in the formation of the quinoline (70 %). On the other hand, [RhCl(COD)]2 is effective for the formation of compounds such as 46. Reaction 23 can be applied to a variety of nitroarenes and aldehydes [86]. 

The presence of intermetallic mercury compounds (amalgams) can also be established by this test. Several milligrams of the sample are kept at about 100° C (drying oven or hot plate) for 30 to 60 minutes. The microcrucible is covered with PdCl paper. This treatment is suflftcient to volatilize enough mercury to affect the paper, even though amalgams have a lower mercury tension than the free metal. 

Very few rr-bonded alkyne complexes of palladium(ll) have been reported in recent years. Except for two examples of monomeric complexes, most of them are polymetallic derivatives where a metal alkynyl acts as a liquid, as discussed above for some Pd(0) derivatives. These complexes adopt interesting stmctures that conform to the types shown below. They have been synthesized by reaction of a metal alkynyl with [PdCl(7/ -C3H5)]2 or Pd(C6Fs)2(THF)2. Platinum alkynyl complexes are the most common ligand frame used, as shown in structures 76-79, but other metal alkynyls can play the same role, such as the Rh and Ir alkynyls depicted 80 and 81. The 7 -alkyne moieties bound to palladium are rotated out of the Pd-coordination plane. The angles of the vectors and the normal to the... 

Besides acrylonitrile and acrylates other functional olefins such as vinyl or allyl compounds can also be dimerized. An important example for vinyl compounds is styrene, which can be dimerized to 1,3-diphenyH-butene. Owing to its high tendency to poljmerize spontaneously, the reaction conditions must be chosen carefuUy. Thus the dimerization catalyzed by PdCl2 at 100 °C yielded only 33% of a dimer fraction with more than 60% of a dark polymeric residue [49]. Using Ni( 1/ -03115)2 as the catalyst, styrene is converted to l,3-diphenyl-/mn5-l-butene [58, 59]. With [PdCl r] -C,U,)] dimers and trimers are obtained (Equation 43) [60]. 

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