Nanotubes fabricated from sandwich-type mixed (porphryinato)(phthalocyaninato)europium complex by template technique

Nanotubes of sandwich-type mixed (porphyrinato)(phthalocyaninato)europium(III) double-decker, H{Eu(TClPP)[Pc(alpha-OC4H9)(8)]} [TClPP = 5,10,15,20-tetrakis(4-chlorophenyl)poprhyrinate; Pc(alpha-OC4H9)(8) = 1,4,8,11,15,18,22,25-octakis(1-butyloxy)phthalocyaninate] were fabricated by using nanoporous anodized aluminum oxide (AAO) membrane as the template. The tubular structure was investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and UV-visible spectroscopy. It was found that the outer diameter of the nanotubes was matched with the pore diameter of AAO membrane very well. HRTEM micrographs reveal that the walls of the nanotubes have orderly layered structure and the distance between the adjacent layers is 0.58 nm, which agrees well with the size (thickness) of one double-decker molecule, indicating that the nanotubes are supramolecular structures formed from the double-decker molecules due to pi-pi interaction between the macrocycles. UV-vis spectroscopic results of the nanotubes also confirmed the formation of J-aggregates of the complex molecules, consistent with HRTEM investigation results.