Ricerc@Sapienza

The results of a potentiometric and calorimetric study on the complexation reactions of neutral N-donor ligands 1,4-diaminobutane (dab) and 1,5-diaminopentane (dap) with silver(I) in dimethylsulfoxide (DMSO) are reported. The investigation is extended for dab ligand to the aprotic solvent acetonitrile (AN), which presents quite different dielectric constant and donor number with respect to DMSO. In both solvents, polynuclear Ag2L 2+2 and Ag2L 2+3 species of high stability are formed, which inhibit the formation of mononuclear ones.

Within the homologous series of amphiphilic peptides AnK, both A8K and A10K self-assemble in water to form twisted-ribbon fibrils with lengths around 100 nm [1]. The structure of the fibrils can be described in terms of twisted -sheets extending in the direction of the fibril, laminated to give a constant cross section of 4 nm by 8 nm.