Copper complexes amido

As part of efforts to develop novel, more efficient, OLEDs, Eisenberg and coworkers have generated the bidentate amine-1,2,3-triazole ligands, 53a-f, and used them to synthesize the heteroleptic copper(I) amido-1,2,3-triazole complexes... 

Fig. 10 The synthesis of heteroleptic copper amido-l,2,3-triazole complexes (54a-f) and the X-ray structure of the heteroleptic copper(I) amido-1,2,3-triazole complex, 54f [169]. Hydrogen atoms and counter ions have been omitted for clarity...

Munro-Leighton C, Delp SA, Alsop NM, Blue ED, Gunnoe TB. A ti-Markovnikov hydroamination and hydrothiolation of electron-deficient vinylarenes catalyzed by well-defined monomeric copper(I) amido and thiolate complexes. Chem. Commun. 2008 111-113. 

Fig. 2.16 Copper-amido complexes as catalysts for the intermolecular hydroamination of electron-deficient alkenes...

The proposed reaction mechanism involves intermolecular nucleophilic addition of the amido ligand to the olefin to produce a zwitterionic intermediate, followed by proton transfer to form a new copper amido complex. Reaction with additional amine (presnmably via coordination to Cn) yields the hydroamination prodnct and regenerates the original copper catalyst (Scheme 2.15). In addition to the NHC complexes 94 and 95, copper amido complexes with the chelating diphosphine l,2-bis-(di-tert-bntylphosphino)-ethane also catalyse the reaction [81, 82]. 

Table 10 gives a listing of methyleneamido complexes. The listing includes several bis(methylene-amido) complexes and representatives from most of the metals in the transition series with the exception of complexes from the copper group. 

Indanes, chromium tricarbonyl complexes, 5, 246 Indazoles, in copper-catalyzed lead reactions, 9, 409 Indenes, chromium tricarbonyl complexes, 5, 246 Indenide derivatives, alkali compounds, 2, 13 Indenones, via imine carbonylation, 10, 136 Indenyl-alkoxo complexes, with Ti(IV), 4, 500 Indenyl-amido complexes, with Ti(IV), 4, 454 Indenyl-amido dimethyl complexes, with Ti(IV), 4, 442 Indenyl bridges, in [Pg.126]

Table 8. Spectrophotometric data and stability constants of copper(II) complexes with poly(amido-amines) (Pm, Pn, P) and their non macromolecular models (Mn, MnP) at 25 °C in 0.1 M NaCl...

It is possible to introduce chirality into the carbene backbone. An interesting approach comes from Michon et al. [33] who synthesised a bis-quinoline substimted chiral imida-zolidin-2-ylidine using enantiomerically pnre (l/ ,2/ )-diaminocyclohexane and (IR,2R)-diphenylethylenediamine as starting materials (see Figure 3.11). The ligands were then utilised to generate the copper(I) carbene and the palladinm(II) amido complexes, respectively. 

A very interesting amido functionahsed carbene was prepared by Legault et al. [116] from A-mesitylimidazole and 0-(2,4-dinitrophenyl)hydroxylamine, an electrophilic ami-nation reagent [117]. The exo-amino group is subsequently acylated to afford a zwitterionic amido functionalised carbene (see Figure 4.38). Reaction with silver(l) acetate and sodium carbonate [a rare variant of the silver(I) oxide method] yields the silver(l) carbene complex as a dimer with a Ag-Ag bond. The silver(l) carbene complex can be used as a carbene transfer reagent to synthesise the homoleptic monomeric copper(Il) carbene complex. 

Other examples of possible zwitterionic buffers can be illustrated by PIPPS, PIPES and EDPS (Jermyn, 1967). EDPS is also a strong complexing agent for copper. A -(2-Acet-amido)glycine, H2NCOCH2NH2CH2COO , pATa 7.7, is a potentially useful buffer but it is not readily available. 

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