Amidate complex

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... 

In contrast, the bulkier ferf-butylamidinate [Bu C(NAr)2] allowed tin(II) mono-halide, -alkoxide, and -amide complexes to be isolated cleanly in high yields. The preparative routes are summarized in Scheme 50. ... 

These complexes show considerable in vitro cytotoxic effects against various tumor cell lines [70, 71[. Moreover, the cationic complexes [Au(N,N, N")Cl[Cl are able to intercalate into ct DNA [71[. Gold(III) amidate complexes of histidine containing... 

Figure 2.12 Amidate complexes of histidine containing peptides, (19) and (20), and of amides of EDTA, (21).

In 2003, Livinghouse et al. also reported that chelating bis(thiophosphonic amidates) complexes of lanthanide metals, such as yttrium or neodymium, were able to catalyse intramolecular alkene hydroaminations. These complexes were prepared by attachment of the appropriate ligands to the metals by direct metalation with Ln[N(TMS)2]3- When applied to the cyclisation of 2-amino-5-hexene, these catalysts led to the formation of the corresponding pyrrolidine as a mixture of two diastereomers in almost quantitative yields and diastereos-electivities of up to 88% de (Scheme 10.81). 

Like the carbodiimide method, the mixed anhydride method results in an amide complex (Table 5, Figure 17). The acid-containing hapten is dissolved in a dry, inert, dipolar, aprotic solvent such as p-dioxane, and isobutyl chloroformate is added with an amine catalyst. The activated mixed anhydride is chemically stable and can be isolated and characterized. The aqueous protein solution is added to the activated acid and the pH is maintained at around 8.5. A low temperature (around 10 °C) is necessary during the reaction to minimize side reactions. 

The trigonal planar zinc phenoxide complex [K(THF)6][Zn(0-2,6-tBu2C6H3)3] is formed by the reaction of a zinc amide complex, via a bis phenoxide, which is then further reacted with potassium phenoxide. TheoX-ray structure shows a nearly perfect planar arrangement of the three ligands with zinc only 0.04 A out of the least squares plane defined by the three oxygen atoms.15 Unlike the bisphenoxide complexes of zinc with coordinated THF molecules, these complexes are not cataly-tically active in the copolymerization of epoxides with C02. The bisphenoxide complex has also been structurally characterized and shown to be an effective polymerization catalyst. 43... 

Treatment of the yellow chloride 159 with lithium diphenylamide gave rise to a thermally stable red iron amide complex [PhB(CH2PiPr2)3]FeNPh2, which was characterized structurally <2004JA6252>. 

Related alkoxides, such as (272), and the amide (277) display a similar activity to the acetate,964 suggesting that both alkoxide and carbonate intermediates are formed during the reaction, ll NMR spectroscopy has been used to demonstrate that (334) reacts reversibly with CHO to generate an alkoxide intermediate which subsequently inserts C02. The amide complex initiates the copolymerization by first inserting C02 into the Zn—N bond and subsequent elimination of trimethylsilyl isocyanate.965... 

Transamination is used for alkaline earth elements and also for early transition metals when the amide complexes are available... 

The mechanism of these reactions may be analogous to that with aldehydes. Arylrhodium(l) complex 188 was shown to undergo insertion of electron-poor aldimines to give amide complex 189, possible intermediates of the catalytic reaction (Equation (64)).4... 

From all the above observations, it was concluded that, for diphosphine chelate complexes, the hydrogenation stage occurs after alkene association thus, the unsaturated pathway depicted in Scheme 1.21 was proposed [31 a, c, 74]. The monohydrido-alkyl complex is formed by addition of dihydrogen to the en-amide complex, followed by transfer of a single hydride. Reductive elimination of the product regenerates the active catalysts and restarts the cycle. The monohydrido-alkyl intermediate was also observed and characterized spectroscopically [31c, 75], but the catalyst-substrate-dihydrido complex was not detected. 

In 1990 Rebek reported an interesting self-replicating systems based on the Kemp s triacid derivative 82 (see Scheme 43) [112-114]. By a combination of hydrogen bonding and tt-tt stacking interactions, diamine 83 forms a binary complex with 82. In such a complex, the amine is ideally positioned to react with the activated ester in 82 yielding the ds-amide complex 84. 

The strained ds-amide complex undergoes a fast isomerisation to the trans-amide species 85 which exposes two hydrogen-bonding binding sites suitable to interact with two new molecules of reactants 82 and 83. Such molecules can then... 

---