Alkylation acetylacetone metal complexes

The chiral ligand (44) was prepared starting from the cyclic a-amino acid (S)-proline80). Recently, similar chiral catalysts and related molybdenum complexes involving optically active N-alkyl-P-aminoalcohols as stable chiral ligands and acetylacetone as a replaceable bidentate ligand, were designed for the epoxidation of allylic alcohols with alkyl hydroperoxides which could be catalyzed by such metal complexes 8,). 

The acetylacetonates are stable in air and readily soluble in organic solvents. From this standpoint, they have the advantage over the alkyls and other alkoxides, which, with the exception of the iron alkoxides, are not as easily soluble. They can be readily synthesized in the laboratory. Many are used extensively as catalysts and are readily available. They are also used in CVD in the deposition of metals such as iridium, scandium and rhenium and of compounds, such as the yttrium-barium-copper oxide complexes, used as superconductors. 1 1 PI Commercially available acetyl-acetonates are shown in Table 4.2. 

Lanthanide aryloxides have proved to be excellent precursors to homoleptic lanthanide alkyls (B, Eq. 13) [140], The reaction can be conducted in non-polar solvents because of the good solubility of the starting compounds. The formation of insoluble alkali metal aryloxides is the driving force (kinetic control). Complexes derived from aliphatic alcohols [141] and acetylacetonates [131] are... 

Stable dihydride complexes of Pd and Pt have been isolated from the reaction of tricyclohexylphosphine with the metal acetylacetonates and aluminium alkyls.28 The pale yellow [PdH2(PCy3)2] has a trans structure from i.r. and n.m.r. studies, with v(Pd—H) occurring at 1740 cm-1. 

Almost every metal in the Periodic Table has been coordinated to a porphyrin of one sort or another. The complexes are usually made by interaction of the ligand with a metal salt in a solvent such as DMF other ways include interaction of the H2porph with metal carbonyls, alkyls, hydrides, or acetylacetonates. The radius of the central hole is fixed, but puckering of the rings can alter it normally it lies between 1.929 and 2.098 A. It is also common for larger metal ions to sit above... 

As for the hydrido compounds, the nmr spectra of alkyl complexes have been studied in detail.35 It may be noted that platinum acetylacetonate complexes often have Pt—C bonds to the "/-carbon atom rather than the usual metal—oxygen bonding, and the acetylacetonate is thus unidentate as in PtCl(acac) (diphos).36... 

The structures of typical ligands were shown earlier in Figure 1.9 and will also be shown later in Figures 3.1 and 3.2. Complexes include some metal halides, hydrates, amines, amides and imides, such as Ti(NR2)4 (R is an alkyl group), oxides, H3B NR3 (a borane-amine adduct), Co(MNT)2 (MNT = maleonitrile dithiolate), Cupc (pc = phthalocyanine), Mo(CO)6, cluster carbonyls, and metal acetylacetonate derivatives. 

The exchange reaction is catalyzed by various metal salts and complexes, such as Cul or CuCN [87], PdCl2(dppf) (dppf, l,l -bis(diphenylphosphino)ferrocene) [88], and Ni(acac)2 (acac, acetylacetonate) [89], allowing for shorter reaction times and the use of reduced amounts of diethylzinc. In the last two cases, the exchange reaction can also be conducted on alkyl bromides and even chlorides. Interestingly,... 

The thermal polymerization of butadiene yields, according to Ziegler et al., a mixture of vinylcyclohexene with at most 15% of cyclooctadiene (95, 96). In 1954 Reed (97) discovered the catalytic cyclodimerization of butadiene to cycloocta-1,5-diene with Reppe catalysts, with a 30-40% conversion at 120-130° C. Wilke et al. recently synthesized a very efficient class of catalyst. If nickel-acetylacetonate is treated with metal alkyls (especially aluminum alkyls) in the presence of electron-donating compounds (mainly cycloolefins), new tt complexes of nickel are obtained which catalyze the cyclo-oligomerization of butadiene (98, 99). Using cycloocta-1,5-diene as the olefinic component, the well-crystallized, faintly yellow bis(cycloocta-... 

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