Copper I Phosphine Complexes

1 Structural Chemistry ofCu(I) Phosphine Complexes and Chelation of Diphosphines 

The cytotoxic potencies of dppe and related diphosphines are potentiated by the presence of Cu(II) salts ° In view of the possibility that chelation of copper in vivo may be involved in the mechanism of action, we need to understand the nature of the copper phosphine species that may be formed. 

Investigations of Cu(I)diphosphine complexes have been restricted to the ligands dppm and dppe, and in general the complexes have been prepared by direct reaction of the phosphine with Cu(I)halide. Complexes with P Cu ratios of 3 1,2 1,3 2,4 3 and 

It will not be an easy task to identify whether a particular Cu(I)diphosphine complex plays a key role in the qdotoxic and antitumour activity of diphosphine ligands. In addition to the variety of possible Cu(I)diphosphine species that could form it is also probable that these species will undergo extensive dissociation in solution. Solution studies of monodentate phosphine complexes of Cu(I)halides have shown that the complexes undergo complicated dissociative equilibria involving species of the form Lm(CuX) with a variety of m n stoichiometries. The extent of the dissociation depends on the solvent, temperature, concentration and the bulkiness of the phosphine  

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The P-diketonate copper(I) phosphine complexes have also been found to be good precursors to the deposition of copper, which occurs through a disproportionation reaction (75) ... 

Complexes of Copper(i).— In most of the copper(i) complexes whose structures have been described during the period of this survey the co-ordination at the metal atom is close to tetrahedral co-ordination numbers of two or three are much less common, while values greater than four are found exclusively in cluster compounds. The structures of mono- and bi-nuclear copper(i)-phosphine complexes have aroused a great deal of interest, and an attempt has been made to explain the observed variations in the lengths of Cu -P bonds. Attention has also been directed at polymeric copper compounds containing bridging halide or pseudohalide ions a number of such systems are described in the section on mixed-valence copper(i)-copper(n) compounds. 

THIOACETALS Methyl iodide. Silver oxide. Triethyloxonium tetrafluoroborate. CONJUGATE ADDITION Cuprous bromide. Dimethylcopperlithium. Tri-n-butyl-phosphine-copper(I) iodide complex. CONVERSION OF - Br TO - OHD Silver sulfate. 

Copper(I) hydride complexes. Stabilization of CuH with various phosphines enables the use of such complexes to reduce carbonyl groups (in the presence of a double bond). ... 

Table 7. Bond lengths and angles in some four-coordinate copper(I) and gold(I) phosphine complexes...

Dang L, Lin Z, Marder TB. DFT studies on the borylation of a,P-unsaturated carbonyl compounds catalyzed by phosphine copper(I) boryl complexes and observations on the interconversions between O- and C-bound enolates of Cu, B, and Si. Organometallics. 2008 27 4443-4454. 

Copper I) chloride, CuCl. White solid (CuClj plus HCJ plus excess copper or SO2). Gives carbonyl and phosphine complexes. 

A potentially interesting development is the microwave-assisted transition-metal-free Sonogashira-type coupling reaction (Eq. 4.10). The reactions were performed in water without the use of copper(I) or a transition metal-phosphine complex. A variety of different aryl and hetero-aryl halides were reactive in water.25a The amount of palladium or copper present in the reaction system was determined to be less than 1 ppm by AAS-MS technique. However, in view of the recent reassessment of a similarly claimed transition-metal-free Suzuki-type coupling reaction, the possibility of a sub-ppm level of palladium contaminants found in commercially available sodium carbonate needs to be ruled out by a more sensitive analytical method.25 ... 

The first copper(I) complex of tris(hydroxymethyl)phosphine ((760) tetrahedral) has been reported by Samuelson and co-workers. This group addressed the question of anion-controlled nuclearity and metal-metal distances in copper(I)-bis(diphenylphosphino)methane complexes, and in this endeavor they reported the structures of complexes (761) (Cu-Cu separation 3.005-3.128 A), (762) (Cu-Cu separation 3.165 A) and (763) (tetrahedral Cu-Cu 3.293 A). 6 They synthesized and provided structural evidence of oxy anion- encapsulated copper(I) complexes of this ligand. The complexes (764) (distorted tetrahedral Cu-Cu 3.143 A), (765) (distorted tetrahedral Cu-Cu 3.424A), (766) (distorted trigonal Cu-Cu 3.170A), and (767) (Cu-Cu 3.032-3.077A) were reported. They studied solid-state emission spectra of these complexes.567 During this pursuit they... 

Ruthenium(II)-NHC systems ean be used for atom transfer radical polymerization (ATRP). Generally, similar results as for the analogous phosphine complexes are obtained. For the ATRP of styrene and methyl methacrylate (MMA) [(NHC)2peBr2] was found to rival copper(I)-based systems and to yield poly (MMA) with low polydispersities. Polymerizations based on olefin metathesis that are catalyzed by ruthenium-NHC complexes are discussed separately vide supra). 

Kneen (4, 31) prepared a series of copper(I), silver(I) and gold(I) complexes containing olefinic tertiary phosphines and arsines for several reasons ... 

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