Although the pioneering example of ortho metalation involving cleavage of C-H bonds was achieved using a nickel complex (Kleiman, J. P.; Dubeck, M. J. Am. Chem. Soc. 1963, 85, 1544), no examples of catalysis using nickel complexes have been reported. In this work, the Ni-catalyzed transformation of ortho C-H bonds utilizing chelation assistance, such as oxidative cycloaddition of aromatic amides with alkynes, has been achieved.
A new type of carbonylation of the ortho C-H bonds in aromatic amides 1, in which the pyridin-2-ylmethylamino moiety functions as a bidentate directing group, can be achieved. The presence of ethylene as a hydrogen acceptor and also of H(2)O, probably for the generation of an active catalytic species, is required. A wide variety of functional groups, including methoxy, amino, ester, ketone, cyano, chloro, and even bromo substituents, can be substituted for aromatic amides. The complex 9 was isolated by the stoichiometric reaction of 1b and Ru(3)(CO)(12), in which 1b binds to one Ru atom in the expected N,N fashion and the carbonyl oxygen binds to the other Ru atom as an O donor.
Heterogeneous reactions of nitrogen monoxide on illuminated TiO2 catalysts in 1 mol dm−3 HClO4 were studied by electrochemical analysis. Nitrogen monoxide was reduced to ammonia and hydrazine. The main reaction was found to be a chemical reaction of hydroxylamine as a reaction intermediate with nitrogen monoxide to give molecular nitrogen. Nitrate was detected as an oxidation product formed by the counterpart reaction of the reduction of nitrogen monoxide.
The thermal behaviour of electrode materials during heat treatment from 250-400 ~ was studied. The cathode performance changed by two steps depending on temperature of the heat treatment. At the first step (300 320 ~ polytetrafluoroethylene (PTFE) melted unexpectedly, giving hydrophobic character to the catalyst layer. This change drastically improved the cathode performance. At the second step (340-400 ~ support carbon was oxidized by catalytic action of platinum, increasing the PTFE content from 45 to 83 wt%. This caused a gradual decline in the cathode performance. The poor cell performance of the electrode treated below 300~ is due to the fact that PTFE is not melted at that temperature. Triton X-100 used as a surfactant in the PTFE dispersion disappeared completely from the electrode at these temperatures by oxidation, catalysed by platinum.
To well understand the mechanism of acid stratification in vented lead-acid batteries, the distributions of sulfuric acid in the vertical direction were measured by a refractive index meter. Also, the measurement of the electrochemical potential distributions in the vertical direction was tried using four dynamic hydrogen electrodes (DHEs). The acid stratification and its relaxation were confirmed by the measurement of sulfuric acid distributions during the charge/discharge and the rest state. There was a difference of four times in the time constant of the acid stratification relaxation between the upper part (top) and the lower part (bottom). This suggests that the acid diffusion is not a dominant reaction of the acid stratification relaxation. The local charge and discharge simultaneously must be occurred on the positive and negative electrode individually due to the electrochemical potential difference. In other words, the electrochemical potential difference probably is the dominant driving force of the acid stratification relaxation. The electrochemical potential distributions in the vertical direction were actually measured using the four DHEs.
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