Proton-assisted self-assemblies of three linear dipyridyl polyaromatic molecules, namely, 4,4′-bipyridine, 1,4-di(4-pyridyl)benzene, and 4,4′-di(4-pyridyl)biphenyl, at the heptanoic acid/highly oriented pyrolytic graphite interface were systematically studied with scanning tunneling microscopy. A major finding was that protons from strong acids could greatly accelerate the assembling processes of 4,4′-bipyridine and 1,4-di(4-pyridyl)benzene molecules and, in the case of 4,4′-di(4-pyridyl)biphenyl molecule, lead to structural transformation in the self-assembling process in analogy to the role of a catalyst in a catalytic process. The experimental results could be rationalized by a simple mechanism involving proton-assisted formation of intermolecular hydrogen bonds, which provides new insights with regards to the self-assembling processes in solutions, especially under acidic bioenvironments.

Two-dimensional crystalline body-centered cubic Mo and face-centered cubic Cu nanonets were prepared on anodized aluminum oxide (AAO) template. The pore size and interpore distance of the prepared Mo and Cu nanonets in this study were measured to be 60−80 nm and 100−120 nm, respectively. These parameters could be feasibly tuned by controlling the electrochemical parameters during the preparation of the AAO template. These nanonets obviously combine the advantages of the structure ordering of single crystals and fairly large specific surface areas of crystallites and powders, and hence could serve as model systems to explore their applications in fields like catalysis, fuel cells, and plasmonics.