Abstract:The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal activity and membrane-damaging activity. 1-Dodecanol and 1-tridecanol had the highest antibacterial activity among the long-chain fatty alcohols tested, but had no membrane-damaging activity. Consequently, it appears that not only the antibacterial activity but also the mode of action of long-chain fatty alcohols might be determined by the length of the aliphatic carbon chain.

This paper investigates a new metal complex that expands the life‐span of an insulator thin‐film formed from anodically‐oxidized alumina in an aluminum electrolyte capacitor. The insulator thin‐film was generally unstable in an electrolytic water solution because of hydrate dissolution. However, in an electrolytic solution containing H2PO4– ions and the organic acid diethlenetriamine‐N,N,N',N',N̋,N̋‐pentaacetic acid (H5dtpa), the life‐span of the insulator thin‐film was remarkably expanded to more than 10000 h because the protective membrane on the anodic alumina electrode was stabilized. The stabilization effects of two complexes, [GaIII(H2dtpa)(H2O)] (1) and [InIII(Hdtpa)Na(H2O)3] (2), were investigated using leak current, 31P‐NMR, and ESI‐TOF‐mass measurements. In 1 only, the life‐span of the anodic alumina electrode expanded, while in 2, an electrical connection through the insulator thin‐film due to hydrate dissolution caused a rapid explosive release of hydrogen gas. The differences in these results were attributed to the free amino‐bis(methylcarboxyl) group in 1, which recognized H2PO4– to form a protective alumina membrane.