Dinuclear copper bridged

Other amidinate anions normally form dinuclear copper(I) complexes with bridging amidinate ligands, although tetracopper(l) complexes have also been reported Silver(1) forms dimeric complexes with functionalized N,N -... 

Catalytically active species derived from 4. Spectrophotometric titration of the backbone ligand of the sngar discriminating dinuclear copper(ll) complex N, N-bis[(2-pyridylmethyl)-l,3-diaminopropan-2-olato] (//-acetato) dicoppeftll) perchlorate (Cu2(bpdpo), 4) in the presence of two equivalents of copper(ll) ions with sodium hydroxide indicates successive replacement of the bridging acetate anion bound in the sohd state with two hydroxyl ions and two water molecnles in alkaline aqneons solntion (eqs. 2 and 3) (20-22). Two species, [Cu2(L h)(OH)] (4a) and [Cn2(L h)(OH)2] (4b), are thus observed in a pH-dependent equihbrium (20). 

In order to introduce more flexibility into the structure of dinuclear copper(II) complexes, bridging ligands of type Y, such as p-XYLpy2 (261),595 have been combined with simple anion bridging ligands, such as Cl-, OH-, (CN)-, (OPh)- and (N3)-, to produce very asymmetric... 

Table 33 Dinuclear Copper(II) Complexes with Bridging Organic Groups...

In marked contrast, l,5-bis(2-carboxyphenyl)-3-cyanoformazan reacted with copper(II) acetate in methanol to give a complex containing water which could not be removed by conventional physical methods. Further, the product was not converted into an anionic complex on treatment with potassium acetate. The clear implication of this is that one carboxyl group is not coordinated to the copper ion and structure (183) is preferred to (184) proposed earlier.129 It is, of course, possible that the complex has a dinuclear, oxygen-bridged structure of the type proposed for the... 

Menif, R. Reibenspies, J. Martell, A. E. Synthesis, protonation constants, and copper(II) and cobalt(II) binding constants of a new octaaza macrobicylic cryptand (MX)3crystal structures of the cryptand and of the carbonato-bridged dinuclear copper(II) cryptate, Inorg. Chem. 1991, 30, 3446-3454. 

This type of active site is also known as a mixed-valence copper site. Similarly to the type 3 site, it contains a dinuclear copper core, but both copper ions have a formal oxidation state of +1.5 in the oxidized form. This site exhibits a characteristic seven-line pattern in the EPR spectra and is purple colored. Both copper ions have a tetrahedral geometry and are bridged by two sulfur atoms of two cysteinyl residues. Each copper ion is also coordinated by a nitrogen atom from a histidine residue. The function of this site is long-range electron transfer, and it can be found, for example, in cytochrome c oxidase [12-14], and nitrous oxide reductase (Figure 5.1 e). 

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