Copper® halide complexes

Axelrad, G., Laosooksathit, S., and Engel, R., Reactions of copper halide complexes of trivalent phosphorus with vinylic halides, /. Org. Chem., 46, 5200, 1981. 

Fig. 6 Representation of the metal and phosphorus environments in copper halide complexes with a Tyh/yhbridging bis-triphenylphosphonio-benzophospholide. The unsym-metric bridging mode is exemplified by the different P-Cu distances (in pm, data from [45] (a) and [53] (b))...

The procedures described below have consistently given stable, crystalline products for a number of tertiary phosphine copper hydride complexes. These complexes can be prepared by the careful reaction of lithium tetrahydrido-aluminate(l-) with tertiary phosphine copper halide complexes. The reactions are run in etheral solvents under an inert atmosphere. The resultant products are... 

Bromo-enamides have been reported to give radical cyclization in excellent yields (82-99%) to p-lactams using catalytic amounts (30%) of tripyridylamine (TPA) copper halide complex [184]. The p-lactam developed under mild conditions via 4-exo bromine atom transfer and subsequent elimination of the tertiary bromide that could be readily achieved by reaction with DBU (Scheme 83). 

Of particular interest are the solubilities of cobalt-, nickel- and copper-halide complexes in dense supercritical aqueous phases. Aquo- and halide complexes have higher coordination numbers at higher density. Several of gaseous solutions are highly coloured (for example dark blue cobalt-II solutions). Visible and UV-spectra, which permit to determine the stability ranges of various complexes have been reported by us up to 500 °C and 6000 bar [43-45]. The results may have interest for hiture catalyst developments. We have used near-UV spectroscopy to determine the solubility of organic solids in various dense gases. Examples are anthracene [46] and caffeine [47] to 200 °C and 2000 bar. Supercritical extraction has become a widely applied procedure in the food, pharmaceuticals and other industries. 

The copper-halide complexes are precursors to the catalytically active species generated upon addition of the Grignard reagents. To determine their stmcture, detailed and H-NMR spectroscopic studies were carried out at —60°C. On the basis of these experiments, it was inferred that the monomeric complex C2, relevant for catalysis, is formed from complex Cl and the Grignard reagent (MeMgBr) (Scheme 31). 

Dithiocarbamate complexes of copper have been sythesized at a high rate. Reports of new complexes include the morpholine-4- (44), thio-morpholine, AT-methylpiperazine-4-, and piperidine- (291) dithiocarba-mates. Novel, polymeric complexes of the type Cu(pipdtc)2 (CuBr) in = 4, or 6) and Cu(pipdtc)2 (CuCl)4 have been prepared by reactions of[Cu(pipdtc)2] with the respective copper halide in CHCla-EtOH (418). The crystal structures of the polymers are known to consist of sheets of individual [Cu(pipdtc)2] molecules linked to polymeric CuBr chains via Cu-S bonds. A series of copper(I) dtc complexes have been the subject of a Cu and Cu NQR-spectral study (440). 

In this case the decisive redox process, which would be specifically inhibited by the hydroquinone, would be the formation of the copper(I) complex corresponding to a monoelectronic transfer from copper(O) to the aryl halide. 

The reaction on unactivated halides can also be done with copper halide catalysts (the Hurtley reaction), and with palladium complex catalysts. 

The platinum metals are valuable by-products from the extraction of common metals such as copper and nickel. The anodic residue that results from copper refining is a particularly important source. The chemistry involved in their purification is too complicated to describe here, except to note that the final reduction step involves reaction of molecular hydrogen with metal halide complexes. 

Li, D., Che, C.-M., Kwong, H.-L. and Yam, V.W.-W. (1992) Photoinduced C-C bond formation from alkyl halides catalysed by luminescent dinuclear gold(I) and copper(l) complexes. Journal of the Chemical Society, Dalton Transactions, 3325-3329. 

Copper(II) complexes of 2,6-lutidylphenylketone thiosemicarbazone, 38, have been prepared from copper(II) chloride and copper(II) bromide [186]. Similar to 2-pyridyl thiosemicarbazones, 38-H coordinates via the ring nitrogen, the azomethine nitrogen and the thiol sulfur based on infrared spectral assignments. Magnetic susceptibilities and electron spin resonance spectra indicate dimeric complexes and both are formulated as [Cu(38-H)A]2 with bridging sulfur atoms. The electronic spectra of both halide complexes show band maxima at 14500-14200 cm with shoulders at 12100 cm S which is consistent with a square pyramidal stereochemistry for a dimeric copper(II) center. 

Substituted terpyridine, 4,4, 4"-tris(5-nonyl)-2,2 <5, 2"-terpyridine (tNtpy), is a planar tridentate ligand that was successfully used in homogeneous ATRP of methyl acrylate and styrene [79]. Polymerization of both monomers was controlled and the resulting polymers had relatively low polydispersities (MJMn < 1.2). Similarly to PMDETA, the typical ligand to copper halide ratio used in the polymerization was 1 1. Terpyridine and its derivatives are expected to form tetra-coordinated complexes with copper in which the fourth coordination sphere is occupied by a monodentate ligand (Br-, Cl , solvent, monomer, etc.). Although,... 

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