Catalytic formation of oxygen from water was observed in the photosensitized reaction by trisbipyridineruthenium(II) using manganese dioxide as a redox catalyst and pentaammine chlorocobalt(III) as an electron acceptor in acidic solution. The β- and “activated” materials are found to be the most efficient and specific redox catalysts, and a 230% of O2 yield based on MnO2 is obtained.

No abstract

Cyclodextrin inclusion complexes of viologens with hydrophobic tails increased the stability of the pyridinium moiety of the viologen to hydrogenation, which resulted in up to five times higher efficiency in terms of hydrogen produced per viologen consumed.

We have investigated the correlation between the molecular structures of various organic cations and their binding to rat small intestinal brush border membrane. The binding of small quaternary ammonium compounds such as tetramethylammonium and choline to brush border membrane was not sufficient to inhibit methylchlorpromazine binding. However, lauryltrimethylammonium and cetyltrimethylammonium, both quaternary amines with a long carbon chain, inhibited binding significantly. The inhibition was competitive. When the unbranched hydrocarbon chain of the quaternary amines was extended in steps from C1 (methyl) to C16 (cetyl), the inhibitory effect increased sharply with length from C7 (heptyl) to C16. These results suggest that the size of the hydrophobic part of the molecule is an important factor in binding of quaternary ammonium compounds to the brush border membrane. The structure of the hydrophilic part was another factor. In imipramine-related compounds, the order of binding was N-didesmethylimipramine (primary amine) greater than desipramine (secondary) greater than imipramine (tertiary) greater than methylimipramine (quaternary). However, with the small molecular ethylamine-related compounds, binding properties did not reflect differences in the hydrophilic component. Therefore, the effect of the hydrophilic part may be secondary and may depend on the size of the hydrophobic part. We suggest that organic cations which are amphiphilic can bind to a common binding site on brush border membrane through hydrophobic and/or hydrophilic interactions.