Nickel complexes amides

Plastics Additives. Many claims have been made for the use of nickel chemicals as additives to various resin systems. By far the most important appHcation is as uv-quenchers in polyolefins (173,174). Among the useful nickel complexes in these systems are dibutyldithiocarbamate nickel [13927-77-0], nickel thiobisphenolates, and nickel amide complexes of bisphenol sulfides (175). The nickel complex of... 

Di(carbene)gold(I) salts, oxidation, 2, 293—294 Dicarbido clusters, with decarutheniums, 6, 1036 Dicarbollide amides, with tantalum, 5, 184 Dicarbollide thorium complexes, synthesis and characterization, 4, 224—225 Dicarbollyl ligands, in nickel complexes, 8, 185 Dicarbonyl complexes arylation with lead triacetates diastereoselectivity, 9, 389 enantioselectivity, 9, 391 mechanisms, 9, 387 reaction examples, 9, 382 indium-mediated allylation, 9, 675 with iridium, 7, 287 reductive cyclization, 10, 529 in Ru and Os half-sandwiches, 6, 508 with Zr—Hf(II), 4, 700... 

It is believed that such reactions proceed through aryne intermediates. These aryne intermediates have been confirmed by reactions of an isotopically labeled chlorobenzene with potassium amide in liquid ammonia1011. Additionally, aryne intermediates have been observed in flash-photolysis experiments and in mass spectrometry12 and trapped as a stable nickel complex (Figure 1), which was characterized by 111 NMR spectroscopy13. 

As an unexpected result of our investigations on the arylation of amines, a new catalysis with nickel complexes was pointed out for the aminolysis of nitriles indeed, in the reaction of the p-bromobenzonitrile with the 4-phenylpyridine in the presence of catalytic amounts of NiBr2, in addition to the expected arylamine, the amide resulting from the aminolysis of the cyano group (and subsequent hydrolysis during the work-up) was isolated (eqn. 8). 

Holm and coworkers found that thiolates, amidates and oximates were most effective at making higher nickel oxidation states accessible (25), However, the studies noted in the previous section showed that in O2 reactions of their Ni(II) complexes, amidates and thiolates were themselves readily oxidized in a manner that precludes catalysis. Oximates have been shown to support stable nickel complexes in both the Ni(III) and Ni(IV) oxidation states (26-28), They also lack the a- and P-hydrogen atoms that are most prone to oxidative abstraction by high valent metals, thereby additionally satisfying the second design criterion. 

Klabunde and Ittel reported the use of nickel complexes containing the phosphorus—oxygen chelating ligands to homo- and copolymerize ethylene with a variety of functional olefins.Negative results were obtained with both vinyl acetate and methyl methacrylate, but copolymers could be obtained if monomers with at least two methylene spacers between the olefin and polar group, lihe functionalities successfully tolerated include ester, trimethyl-silyl-protected acids, ketones, fluoro groups, and 2° amides. 

Figure 9.7 Electrografting of amine groups on MWCNTs and postfunctionalization with complex 2 through amide links [51], This is a simplified representation of the structure of the material for sake of clarity The number of phenylene residues is indeed arbitrary and attachment of the nickel complex to two or more surface amine groups not excluded.

In addition, reductive elimination of palladium and nickel complexes to form esters (Equations 8.67 and 8.68), amides, and tiiioesters has been reported. -" The reductive eliminations of esters and amides were observed during mechanistic studies on the palladium-catalyzed formation of esters and amides from aryl halides, carbon monoxide, and alcohols or amines. This catalytic process is presented in Qiapter 17 (carbonylation processes). The reductive elimination of thioesters from nickel complexes were studied, in part, to understand the C-S bond-forming process of acetyl coenzyme A synthase. Prior to this work, an iron-mediated synthesis of p-lactams had been reported that appears to occur by reductive elimination to form the amide C-N bond of the lactam. ... 

The Xyl /X2- -imidoyl complex can be carbonylated to give a bicyclic amide nickel complex, whose formation presumably involves the intramolecular coupling of acyl and imidoyl groups (Equation (7)). 

New Cj-symmetric nickel complexes of a-amino amides catalyse enantioselective addition of dialkylzincs to aldehydes DFT studies suggest that the aldehyde carbonyl, rather than coordinating to the metal, is activated by an amino hydrogen which has been acidified by the nickel complexation. 

The stabilizer must not react in an unfavourable manner with the polymer. Nickel complexes cannot be used in nylon polymers because the nickel complexes with the amide groups. 

---