Ruthenium EDTA complex

Bond lengths for a number of the ruthenium EDTA complexes are given in Table 1.12. 

A considerable number of EDTA complexes of ruthenium have been synthesized [130-132] there has been interest in their catalytic potential while several compounds have had their structures determined. Synthetic routes relating to these compounds are shown in Figure 1.50. 

Figure 2.43 Ruthenium and rhodium EDTA complexes. Comparative bond lengths are given in...

Ru(edta)(H20)] reacts very rapidly with nitric oxide (171). Reaction is much more rapid at pH 5 than at low and high pHs. The pH/rate profile for this reaction is very similar to those established earlier for reaction of this ruthenium(III) complex with azide and with dimethylthiourea. Such behavior may be interpreted in terms of the protonation equilibria between [Ru(edtaH)(H20)], [Ru(edta)(H20)], and [Ru(edta)(OH)]2- the [Ru(edta)(H20)] species is always the most reactive. The apparent relative slowness of the reaction of [Ru(edta)(H20)] with nitric oxide in acetate buffer is attributable to rapid formation of less reactive [Ru(edta)(OAc)] [Ru(edta)(H20)] also reacts relatively slowly with nitrite. Laser flash photolysis studies of [Ru(edta)(NO)]-show a complicated kinetic pattern, from which it is possible to extract activation parameters both for dissociation of this complex and for its formation from [Ru(edta)(H20)] . Values of AS = —76 J K-1 mol-1 and A V = —12.8 cm3 mol-1 for the latter are compatible with AS values between —76 and —107 J K-1mol-1 and AV values between —7 and —12 cm3 mol-1 for other complex-formation reactions of [Ru(edta) (H20)]- (168) and with an associative mechanism. In contrast, activation parameters for dissociation of [Ru(edta)(NO)] (AS = —4JK-1mol-1 A V = +10 cm3 mol-1) suggest a dissociative interchange mechanism (172). 

The ruthenium(III) complex of edta in which the ligand acts only as a five-coordinate species and in which an acetate arm remains free, exists in three pH-related forms ... 

PVP may react with dichlorobis(2,2 -bipyridyl)ruthenium(II) and the precomplexed polymer may then be used to dip coat various electrodes.52 EDTA complexes of ruthenium(III) will react with PVP and may thereby be immobilized on electrodes. The use of transparent graphite electrodes facilitates the spectroscopic monitoring of both the quantity of PVP and ruthenium on the electrode. Also the Ru111 -+ Ru11 reduction may be followed as it proceeds. The UV spectra of the immobilized EDTA complexes are similar to those in solution. It has been possible to use a band... 

The electroactivity of a redox polymer may depend upon the solvent with which the surface modified electrode is in contact. Thus, for example, PVP containing an EDTA complex of ruthenium(III) is electroactive in contact with aqueous media, but inactive in contact with solvents such as dimethyl sulfoxide. 

Ruthenium(III) edta complexes can be attached to a graphite electrode surface via the uncoordinated carboxylate function and some redox couples for several [Ru(edta)L]- 2- complexes are reported.238... 

The ruthenium(III) complex is oxidized to a paramagnetic ruthenium(V) species, RuO(EDTA) p=l.9Sfi z/(Ru=0) 890cm ) by NaOCl or... 

When rare-earth-metal ions such as Eu and Tb are bound to polyelectrolyte membranes such as poly(sodium acrylate) and poly(sodium ethene-sulphonate) their fluorescence intensities are considerably enhanced this is associated with the formation of asymmetric bonds between the rare-earth ions and the acrylate/S03 groups in the polymers. This was confirmed by the addition of EDTA to the Tb -poly(sodium acrylate) complex which, because of its preferential binding to the polymer, displaced Tb ions and resulted in reduced fluorescence of the latter. Stokes shifts of fluorescent dyes in different polymer systems have been related more to mobility effects in the polymer than polarity,and the fluorescence of hydrolysed aspirin has been found to be affected by the nature of different polymer supports.The luminescence properties of cis-(2,2 -bipyridyl)ruthenium(ii) complexes have been found to be influenced by binding the complex to a polymer matrix,as have the luminescence properties of flavones and l-octadecyl-3,3-dimethyl-6 -nitrospiro(indoline-2,2 -2H-benzopyran). Other studies of interest in-... 

Taqui Khan et al. reported that the photoreduction of N2 to NH3 was catalyzed by a number of different ruthenium(II) complexes of the general formula [RuL(N2)]" in aqueous suspensions of a Pt-CdS-RuOz particulate system [114]. The ruthenium complexes used were [Ru(EDTA)N2]2 4, [Ru(HEDTA)N2] 5, [Ru(PDTA)N2]2 6, [Ru(CDTA)N2]2 7, [Ru(H2DTPA)N2]" 8, and [Ru(HIMDA)N2] 9. Ruthenium complexes were characterized by FTIR, H-NMR, and UV-visible spectroscopies, and differential pulse polarography (DPP). The particulate system Pt-CdS-Ru02 was prepared by the procedure of Kalyanasundaram et al. [115]. 

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