Platinum complexes electrochemistry

Lane, R. T., and Hubbard, A. T. Electrochemistry of chemisorbed molecules. 11, The iiitlu-ence of charged chemisorbed molecules on the electrode reaction.s of platinum complexes. /. Phys. Chem. 1973, 77, 1411-1421. 

Although the Initial use of glassy carbon as an electrode material Indicated that It might be a viable substitute for platinum (1), subsequent Investigations have shown that glassy carbon Is quite complex as an electrode material. The conditions used to manufacture a particular sample of glassy carbon and the subsequent steps used to treat the surface for electrochemistry strongly Influence Its behavior, possibly even more so than with platinum. 

A review9 with more than 37 references includes an examination of symmetry groups and chirality conditions for C60 and C70 bonded to one or two metals in rf and/or rf fashion. Palladium and platinum rf complexes of C6o and C70 are described (novel synthesis, NMR spectra, electrochemistry) as well as first optically active organometallic fullerene derivatives. 

The synthesis, X-ray structure, NMR, and UV-visible spectroscopy, and electrochemistry of a macrocyclic platinum(II) complex containing the tetradentate 1,4,7,10-tetrathiacyclodecane ligand, [12]aneS4 (144) have been reported.350 Related complexes including [Pt([13]aneS4)]2+ and [Pt([16]aneS4)]2+ have also been prepared, and molecular mechanics calculations complemented... 

Zinc dithiocarbamates have been used for many years as antioxidants/antiabrasives in motor oils and as vulcanization accelerators in rubber. The crystal structure of bis[A, A-di- -propyldithio-carbamato]zinc shows identical coordination of the two zinc atoms by five sulfur donors in a trigonal-bipyramidal environment with a zinc-zinc distance of 3.786 A.5 5 The electrochemistry of a range of dialkylthiocarbamate zinc complexes was studied at platinum and mercury electrodes. An exchange reaction was observed with mercury of the electrode.556 Different structural types have been identified by variation of the nitrogen donor in the pyridine and N,N,N, N -tetra-methylenediamine adducts of bis[7V,7V-di- .vo-propyldithiocarbamato]zinc. The pyridine shows a 1 1 complex and the TMEDA gives an unusual bridging coordination mode.557 The anionic complexes of zinc tris( V, V-dialkyldithiocarbamates) can be synthesized and have been spectroscopically characterized.558... 

In 1986, Breikss and Abruna reported electrochemical and mechanistic studies on a close analogue of the rhenium complex, (Dmbpy)Re[CO]3Cl, where Dmbpy = 4,4 dimethyl 2,2 bipyridine. The cyclic voltammogram of the complex at platinum in CH3CN/tetrabutylammonium perchlorate is shown in Figure 3.56 for simplicity we will consider only the electrochemistry taking place above c. —2.3V vs. SCE. 

Although there has heen a great deal of research concerning how platinum(II) complexes hind to biological molecules and the hkely mechanism of antitumor activity of these platinum-containing species, far less attention has heen paid to the properties of other metal complexes in this arena. Recent attention has fallen on cohalt(II)-Schiff hase complexes, as several have heen discovered to have promise as antiviral agents. A review of recent work has appeared elsewhere [64], so the topic will not he covered here however, in addition to focusing on recent developments, emphasis is placed on the introduction of the new head unit, 3,6-diformylpyridazine (13), into Schiff-hase macrocyclic electrochemistry. 

An additional interpretation issue involves the presence of oxidation reactions that are not metal dissolution. Figure 28 shows polarization curves generated for platinum and iron in an alkaline sulfide solution (21). The platinum data show the electrochemistry of the solution species sulfide is oxidized above -0.8 V(SCE). Sulfide is also oxidized on the iron surface, its oxidation dominating the anodic current density on iron above a potential of approximately -0.7 V(SCE). Without the data from the platinum polarization scan, the increase in current on the iron could be mistakenly interpreted as increased iron dissolution. The more complex the solution in which the corrosion occurs, the more likely that it contains one or more electroactive species. Polarization scans on platinum can be invaluable in this regard. 

The Pt-H atom interaction plays a key role in electrochemistry, particularly at the Pt/aqueous solution interface in the range of the potentials related to the H-adatom electrosorption equilibrium and hydrogen evolution reaction. The situation outlined above suggested the convenience of attempting a quantum chemistry approach to surface species that are likely formed at a simulated platinum/aqueous electrochemical interface in order to discriminate the structure and energy of possible H-adsorbates. This is a relevant issue in dealing with, for instance, the interpretation of the complex electrosorption spectra of H-atoms on platinum in an aqueous solution, as well as to provide a more realistic approach to the nature of H-atom intermediates involved in the hydrogen evolution reaction. 

R 102 M.R. Bermejo, A.M. Garda-Deibe, A.M. Gonzalez, O.L. Hoyos, M. Maneiro and M. Rey, The Diversity Observed in Manganese(III)- Schiff Base Complexes Models for a Variety of Biological Systems , p. 61 R 103 L.M. Mink and R.K. Boggess, Platinum(II) and Platinum(IV) Tetra-phenylporphyrin Complexes Synthesis, Characterization, and Electrochemistry , p. 125... 

The electrochemical deposition of a metallic-ruthenium film is very difficult compared with that of other platinum-group elements [46, 61, 91-93]. One of the reasons may be related to the comphcated electrochemistry of ruthenium deposition and the stability of the Ru-chloro complex [92]. For example, it has been reported that the RuCfi species in HCIO4 solution is decomposed partly into RuO +, in which Ru(IV) is present [94]. 

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