Some Behavior and Structures of Leaf-Like Crystals of Copper- and Zinc-Phthalocyanines Vacuum- Deposited by Electron Bombardment

When powderly crystals of Cu- and Zn-phthalocyanines were electron-bombarded in an electron microscope, thin networks of slender leaf-like crystals are formed on the supporting film. By selected area electron diffraction, it was revealed that the newly formed crystals were always the metastable a-form regardless of the crystal form of the original powder in the case of Cu-phthalocyanine. As to Zn-phthalocyanine, similar leaf-like crystals take differnt forms depending on the locality of the substrate film. The stable 14-form was found near the center of the hole of a grid mesh, whereas the metastable a-form appeared on the film near the rim of the same hole. This variation was interpreted on the basis of the temperature distribution of the film caused by the electron irradiation. It is plausible that Zn-phthalocyanine has lower critical point (or so-called transition temperature) than Cu-derivative, at which two temperature ranges where the individual crystal forms are stable is separated. With a cross grating pattern obtained from a large leaf-like lamella of Cu-phthalocyanine, the metastable a-form was interpreted to have a crystal structure different from that reported by Robinson and Klein