Imidates metal complexes

Cyclic selenium imides, e.g., Se7NH, are not available as a source of Se-N anions (Section 6.3). The only example of a metal complex of the [SesN] anion, Pt(Se3N)Cl(PMe2Ph), was obtained by the reaction of Sc4N4 with [PtCl2(PMe2Ph)]2. ... 

A variety of complexes of the thionyl imide anion [NSO] with both early and late transition-metal complexes have been prepared and structurally characterized. Since both ionic and covalent derivatives of this anion are readily prepared, e.g., K[NSO], McsMNSO (M = Si, Sn) or Hg(NSO)2, metathetical reactions of these reagents with transition-metal halide complexes represent the most general synthetic method for the preparation of these complexes (Eq. 7.10 and 7.11). ... 

Sulfur and nitrogen form a variety of binary anions with acyclic, cyclic and cage structures.69,70 The Se-N anions are only known in metal complexes. S-N anions play an important role in the formation of cyclic sulfur imides and as constituents of solutions of sulfur in liquid ammonia. 

In the very recent past, metal complex catalysis has been used with advantage for the stereo- and enantio selective syntheses based on the Henry and Michael reactions with SENAs (454-458). The characteristic features of these transformations can be exemplified by catalysis of the reactions of SENAs (327) with functionalized imides (328) by ligated trivalent scandium complexes or mono-and divalent copper complexes (454) (Scheme 3.192). Apparently, the catalyst initially forms a complex with imide (328), which reacts with nitronate (327) to give the key intermediate A. Evidently, diastereo- and enantioselectivity of the process are associated with preferable transformations of this intermediate. 

The preparation of metal nitrides with N3 reagents typically employs d° metal complexes as starting materials. However, the reactions of r-butyl isocyanate with metal-oxo complexes of OsVI and RuVI represent rare examples of the use N3- reagents with d2-metals. It has been postulated that reaction of the isocyanate with metal-oxo 3 affords a four-membered ring intermediate 4, followed by the extrusion of carbon dioxide to yield r-butyl metal imide 5 (Scheme 1). Elimination of isobutylene from this complex then produces the metal nitride and the isobutylene. 

The ligands that have been used in the preparation of metal nitride complexes are quite varied. They include halides, carbogenic groups (alkyl moiety and Cp ), pnic-togens (amine, amide, imide, phosphine, and arsine), and chalcogens (ether, alkox-ide, oxo, thioalkoxide, and selenides). Chart 1 provides a listing of the various ligands and the associated nitrido metal complexes. 

A method for extracting cadmium, copper, europium, and nickel metal ions from aqueous solution using modified polyethyleneimine is described. The polymer modification consists of grafting an imide, diol, triol, carboxylic acid, or thiocar-boxylic acid function to poly(ethyleneimine), which then forms stable metal complexes that are readily removed from solution. 

Thionyl imide, HNSO, is a thermally unstable gas, which polymerizes rapidly. It can be prepared by the reaction of thionyl chloride with ammonia in the gas phase. It has a planar, cis stmcture according to IR and microwave spectra. Some transition metal complexes of thionyl imide, for example, [M(CO)5(HNSO)][AsFg] (M = Mn, Re), are known. ... 

Transition metal complexes are used as catalysts and as reagents in the synthesis of imides. Molybdenum hexacarbonyl activates strained aziridines and allows the nucleophilic attack of caibanions. Intramolecular rearrangement and a final oxidation yields imides completely stereospecifically (equation 59).38> Dicobalt octacarbonyl catalyzes the conversion of 3,7-unsaturated amides to imides in the presence of carbon monoxide (equation 60). ... 

Moreover, aryl-oxazoles, -imidazoles [17], or-thiazoles [18], anhydrides [19], and imides [20] are accessible via intramolecular Heck-type carbonylations. In addition to typical acid derivatives, aldehydes [21], ketones [22], aroyl cyanides, aroyl acetylenes, and their derivatives [23] could be synthesized via nucleophilic attack of the acyl metal complex with the corresponding hydrogen or carbon nucleophiles. Even anionic metal complexes like [Co(CO)4] can act as nucleophiles and lead to aroylcobalt complexes as products [24]. 

A main question - not yet really considered - concerns the inertness of ionic liquids. Not only are the anions potential ligands, especially for neutral and cationic metal complexes one has also to take into consideration what is known for cations like (imid)azolium formation of carbene complexes via deprotonation is a rather facile process especially if ligands of sufficient basicity are present, e. g., -OR, -NR2. Therefore, several of the impressive catalytic results [113] deserve mechanistic investigation to find out whether they are really limited to the ionic liquid effects. For example, solvent and complexation effects are likely to enhance one another in the Heck coupling reactions that were run in the presence of Structure 18, Scheme 11 [115]. 

Many metal complexes with chiral ligands such as phosphines, phosphites, or imidates will catalyze asymmetric hydrogenations, hydrosilylations, and the like. Extremely high enantioselectivities have been achieved with a wide variety of substrates. 

The reaction of PhINTs with complexes of ruthenium(II) [800], osmium(II) [850,851] and cobalt(III)[852] results in imidation at the metal center with the formation of the respective tosylimido-metal complexes. X-Ray structures have been determined for several bis(tosylimido)ruthenium(VI) and bis(tosylimido)-osmium(VI) porphyrin complexes [800, 850, 851]. 

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