Copper complexes Cu

Copper and brasses in the systems are more resistant to corrosion because of a stable oxide film however, if ammonia is present together with oxygen, corrosion of copper and copper oxide rapidly occurs. The corrosion is an oxidation process and results in the formation of the ammonia-copper complex [Cu(NH3)42+], Corrosion of nickel and zinc components also may occur in like fashion. 

Figure 3 Dimeric monoalkyl copper complexes, Cu[/j-NRC BuC(H)R]2 5 (R=SiMe3) and Cu2(2-C(SiMe3)2-6-MePy)2 6. Compound 5 Hitchcock, P. B. Lappert, M. F. Layh, M. Dalton Trans. 1998, 1619 - reproduced by permission of The Royal Society of Chemistry. Compound 6 Van den Anckor, T. R. Bhangava, S. K. Mohr, F. Papadopoulos, S. Raston, C. L. Skelton, B. W. White, A. H. Dalton Trans. 2001, 3069 - reproduced by permission of The Royal Society of Chemistry.

The magnesium complex 34 was demetalated with trifluoroacetic acid to produce the H2[pz(A3B1)] (35) (98%) followed by conversion into the corresponding copper complex Cu[pz (A3B x)] (36, 95%) with Cu(II) acetate. Alternatively, Compound 36 can be prepared directly from the magnesium complex 34 by treatment with trifluoroacetic acid in the presence of Cu(II) acetate (72%). All forms of the norbomadiene substituted pz precursors, M[pz (A3Bj)] A = dipropyl, B = benzonorbomadiene M = Mg, H2, Cu, 34-36, have... 

A typical nitrogen ENDOR spectrum of a copper complex (Cu(sal)2) with two magnetically equivalent 14N nuclei and with the EPR observer at mF = 0 (two sets of six ENDOR lines) is shown in Fig. 9. The pronounced splitting of the lines into a doublet structure is described by the term 4/Jai. The splitting of the more intense lines by 4/ a3 is not resolved (see B5). 

The copper complex Cu(bipyam)2(C104)2 diluted into the corresponding Zn host crystal1055 shows an ENDOR spectrum which is due to four magnetically nonequivalent... 

Nitrogen ENDOR. The nitrogen hfs tensor is nearly axially symmetric with the largest principal axis oriented approximately along the Cu-N bond direction (<(Cu-N, A ) = 7°). A very similar result has been reported by Moores and Belford168 for the planar copper complex Cu(msal)2. 

The valency of the complex radicle is the same as that of the central metallic atom when the complex contains only ammonia, substituted ammonia, water, or other neutral group. For example, cobalt in eobaltie. salts is trivalent, and the cobalt complex with ammonia, Co(NI13)8 ", is likewise trivalent copper in cupric sulphate is divalent, and the copper complex, [Cu(NH3)4] , is also divalent. In the same wn.y [Co(NH3)5.H30] " and [Co(NII3)4.(II20)2] " are trivalent, as also [Co(NH3)2.en2]" and [Co.en3] ", where en represents cthyleucdiamine, CH NH2... 

Infrared spectra have been recorded for the parent tetrazole (ttaH), its sodium salt, and a range of transition metal derivatives (94). In subsequent work the infrared spectra of sodium tetrazolate and of the copper complex Cu(tta)2 H20 were assigned and a vibrational analysis was reported for the tetrazolate anion (77). Infrared data have been... 

Ni(C6HsN)4(NCS)2]6,18 81 has been recommended for the ther-mogravimetric determination of nickel or thiocyanate.82-88 The emerald-green chloroform-soluble copper complex [Cu(C5H5N)2-(NCS)2] has been suggested for the detection of copper, pyridine, or thiocyanate.84... 

Since the copper complexes, [Cu(NN)2]+ and [Cu(NN)(PR3)2]+ (NN = 1,10-phenanthroline, 2,2 -bipyridine, and their derivatives) were applied to stoichiometric and catalytic photoreduction of cobalt(III) complexes [8a,b,e,9a,d], one can expect to perform the asymmetric photoreduction system with the similar copper(l) complexes if the optically active center is introduced into the copper(I) complex. To construct such an asymmetric photoreaction system, we need chiral copper(I) complex. Copper complex, however, takes a four-coordinate structure. This means that the molecular asymmetry around the metal center cannot exist in the copper complex, unlike in six-coordinate octahedral ruthenium(II) complexes. Thus we need to synthesize some chiral ligand in the copper complexes. 

The synthesis of Bpph,4CN has been reported by Eichhorn and coworkers.174 The monomeric homoleptic square-planar copper complex [Cu(BpPh,4GN)2] has been prepared by the reaction of... 

Bis- and tris(hexafluoro-2,4-pentanedionato) (hexafluoroacetyl-acetonate, hfa) complexes of 23 different metal(II), (III), and (IV) ions have been prepared.1 5 Most of these have been isolated as low-melting solids, which can be readily sublimed unchanged between 25 and 150°. Most methods of synthesis of this class of complexes in different solvents have resulted in incomplete conversion to the chelate. For example, the copper complex Cu(hfa)2 has been prepared in 80% yield using excess ligand as the solvent. Several solvents having various polarities (water, ethanol, carbon tetrachloride, acetone) have been used. 

The analysis of the experimental M-B distances has also allowed the location of some examples of ionic complexes described in the literature as MLn(q1-BH4). The long Cu-B distances preclude BLC- coordination. These examples are the copper complexes [Cu(Cyclam)]+[BH4]", [Cu(TMAC)]+ [BH4] , (TMAC = CyclamMe4) (see Table 3) and the chromium complex [(py Crtq1 -BH4)]+[BH4] . 

Recent studies with copper phenanthroline complexes expand on the possibilities for site-directed oxidation-reduction chemistry of copper complexes. Cu(ii)(l,10-phenanthroline)2, alone or tethered to various DNA-binding domains, causes DNA strand scission in vitro in the presence of reductants, which involves the formation of the hydroxyl radical or its equivalent." - Upon reaction of Cu(ii)(Phen)2 with tumor cells, it is likely that the complex binds directly to DNA, acting as a site-directed catalyst for the generation of oxyradi-cals. ... 

It can be a Cu -hydroperoxo species formed as in Eq. (17) of Fig. 13. A homolysis of the 0-0 bound could allow the abstraction of a hydrogen atom from DNA that gives rise to a DNA radical and a new copper complex (Cu -0 or its canonical form Cu =0), Eq. (18). This last intermediate may... 

An example to illustrate the above strategy consists of treatment of [Cu(NCMe)4] with 2,9-diphenol-1,10-phenanthroline (20), to give the tetrahedral copper complex [Cu... 

Keywords Copper complexes Cu(I) complexes Redox processes Ligand Rate constant Aqueous solutions. 

An EPR and ENDOR investigation of the planar copper complex Cu(sal)2 (Fig. 30) substituted into a single crystal of Ni(sal)2 has been reported by Schweiger et al. The... 

The hydrogen ion dependence is attributed to the inhibition of formation of the copper complex but the mechanism will hold only if [L]>[Cu ]. A similar halforder dependence on Cu is exhibited in the corresponding oxidation of glycollic acid. In this instance, however, the copper complex [Cu(gly)al is involved directly in a redox reaction with the oxidant ... 

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