Platinate 378 Subject

Similar size effects have been observed in some other electrochemical systems, but by far not in all of them. At platinized platinum, the rate of hydrogen ionization and evolution is approximately an order of magnitude lower than at smooth platinum. Yet in the literature, examples can be found where such a size effect is absent or where it is in the opposite direction. In cathodic oxygen reduction at platinum and at silver, there is little difference in the reaction rates between smooth and disperse electrodes. In methanol oxidation at nickel electrodes in alkaline solution, the reaction rate increases markedly with increasing degree of dispersion of the nickel powders. Such size effects have been reported in many papers and were the subject of reviews (Kinoshita, 1982 Mukerjee, 1990). 

The so-called cis-platin has been the subject of numerous studies related to its antitumoral activity (anti-cancerous). For comparison, sila-cis-platin under the form of its salts (chloride A, sulfate B and oxalate C) has been prepared and its anti-tumor activity tested against L-1210 leukemia in male mice.499,500... 

Since Bahnemann and co-workers have observed that a comparatively high amount of trapped holes are formed when partially platinized titanium dioxide particles are subjected to ultra band gap irradiation (cf. Fig. 7.6), they have chosen this system to study the dynamics of the photocatalytic oxidation of the model compounds dichloroacetate, DCA", and SCN- [7]. To explain their experimental observations these authors have used a model assuming two energetically different types of hole traps (see our detailed discussion above). 

An large number of pyrazines were subjected to X-ray crystallographic analysis. Those in the realm of metal complexes included [/i-2,3,5,6-tetrakis(2-pyridyl)pyrazine]bis[chloroplatinum(II)] bis[trichloro(dimethyl sulfoxide-ir5)platinate(II)] 152 <03AX(E)411>, tetraaqua-1,2,4,5-benzenetetracarboxylato(pyrazine)dicobalt(II) dihydrate <03AX(E)841>, polymeric... 

Although the first cyclopropane derivative was obtained as early as 1881, and the parent hydrocarbon just one year later, it was not until 1922 that cyclopropene (1) b ame available. However, Freundler (1897) claimed that the dry distillation of barium furoate led to cyclopropene in addition to furan, but the reaction proved difficult to repeat and the report remains unsubstantiated. Work published by Dem yanov and Doyarenko in 1922 provided the first authenticated synthesis of cyclopropene. These authors found that trimethylcyclopropylammonium hydroxide undergoes Hoffmann elimination by heating to approximately 300°C on platinized clay. This reaction, which parallels the original synthesis of cyclobutene, was subjected to detailed scrutiny in 1941 and under optimum conditions 1 was obtained in a yield of 45 % (equation 1). Despite these early beginnings. 

The first example of the hydrosilylation, that is, the reaction occurring between trichlorosilane and 1-octene in the presence of acetyl peroxide, was reported in 1947 by L. H. Sommer (1), but the discovery in 1957 of hexachloro-platinic acid as a very efficient catalyst by J. L. Speier (2) from Dow Coming became a strategic point for wide and common application of the reaction as one of the most fundamental and elegant methods explored over the next 50 years for laboratory and industrial synthesis of organosilicon and other related silicon compounds, which can also be directly subjected to organic synthesis. 

The dinucleotide of guanine, d(GpG) and d(pGpG), is by far the best understood, and its platinated adduct has been the subject of a full... 

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