Phthalocyanine-Based Nanowires and Nanoparticles

Although Pcs are macrocycles that have a strong tendency to aggregate into columnar stacks by tt-tt stacking interaction, the formation of long-range, ordered aggregates based on these systems has been seldom reported [84,117]. 

In this context, a novel and interesting method for the preparation of such systems has recently been reported. The pyrolysis of a nickel naphthalocyanine (Nc), a homolog of Pc with a larger tt system, previously organized in the nanoscale channels of a porous alumina membrane that acts as a template, leads to the formation of 

1-D nanoribbons and nanowires of different metal-containing Pcs have also been prepared by organic vapor-phase deposition (OVPD), a technique used to fabricate organic millimeter-sized crystals, thin films, or nanostructures [211], Scanning electron microscopy (SEM), TEM, x-ray diffraction (XRD), and absorption measurement studies have revealed that the morphology of the nanostructures was strongly dependent on the chemical nature of the deposited macrocycle, the nature and the temperature of the substrate, and the source-to-substrate distance. 

The growth of Pc-based, 1-D nanostructures on gold nanoparticles has also been achieved via vapor-phase transport, in a process in which the gold nanoparticles act as nucleation sites for the perfluorinated CuPc molecules and promote their anisotropic growth leading to very uniform, 1-D structures with high aspect ratio (Fig.28) [212], 

Pc-based nanoparticles have also been prepared employing a solution-casted method from an optically active metal-free Pc substituted with two binaphthyl units. Surprisingly, when the same process was carried out in the presence of a surfactant, the formation of hollow-sphere nanostructures was observed as revealed by TEM and SEM. Low angle XRD and electronic absorption spectroscopy revealed that these nanoscale hollow spheres are formed by stacked Pc molecules in a face-to-face configuration [213], 

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