Copper complexes, cation, with

The repeating arrangement of the (H20)i3 cluster leads to the construction of a new type of waterpipe, as shown in Figure 52. The inner diameter dimensions of the water tube were found to be 8.527 x 8.061 A. The existence of such unstable pipe (vide supra) has been made possible by interactions with its surroundings, including an Anderson heteropolyanion and a dimeric copper complex cation. 

Fonnation of a complex with a copper cation only further stimulates this behaviour. As a result, S.lg is almost completely bound to the micelles, even at low concentrations of Cu(DS)2. By contrast, the reaction of 5.1 f still benefits from an increasing surfactant concentration at 10 mM of Cu(DS)2. In fact, it is surprising that the reaction of this anionic compound is catalysed at all by an anionic surfactant. Probably it is the copper complex of 5.If, being overall cationic, that binds to the micelle. Not surprisingly, the neutral substrate S.lc shows intermediate behaviour. 

Cations with completely filled d sub-shells. Typical of this group are copper(I), silver(I) and gold(I) which exhibit Class B acceptor properties. These ions have high polarising power and the bonds formed in their complexes have appreciable covalent character. 

Triphenylformazan behaves as a bidentate ligand forming 2 1 complexes (217) with divalent copper, nickel, and cobalt.377 Formazan metal complexes can be compared to complexes of azo dyes or beta diketones due to structural similarity.301,302 In general, formazan metal complexes have low stability toward acids. However, when electron-donating substituents are added to the aromatic ring, a considerable enhancement in stability is observed. Cationic complexes of type 218 are also known. The complexation of formazan with metal cation can be accompanied by oxidation to the tetrazolium salt and the formation of a complex... 

Scheme 61).22 149 150 152 229 230 The methylene-bridged bis(oxazoline)s (70) can afford either neutral copper complexes of the semicorrin type (72) or cationic copper complexes (73). Cyclopro-panation with copper complexes of type (70) shows similar stereochemistry to that with the corresponding copper semicorrin complexes.229-231 Alternatively, bis(oxazoline) ligand (71), bearing... 

Bhat et al. [199] used complexation with the bis(ethylenediamine) copper (II) cation as the basis of a method for estimating anionic surfactants in fresh estuarine and seawater samples. The complex is extracted into chloroform, and copper is measured spectrophotometrically in the extract using l,2(pyridyl azo)-2-naphthol. Using the same extraction system these workers were able to improve the detection limit of the method to 5 pg/1 (as linear alkyl sulfonic acid) in fresh estuarine and seawater samples. 

---