X-form metal-free phthalocyanines

X-form metal-free phthalocyanine 272 X-ray diffraction (XRD) 67 f 335 X-ray powder diffraction, structure solutions from 111... 

Dainippon Ink and Chemicals markets its photoconductive X-form metal-free phthalocyanines as the Fastogen Blue 8120 series. Products include materials for printers and material for plate-making. X-form metal-free phthalocyanine is less... 

Figure 17-6 Transient decay curve of single-layer photoreceptors with X-form metal-free phthalocyanine and Y-form titanyl phthalocyanine.

Dainippon Ink and Chemicals markets its photoconductive X-form metal-free phthalocyanines as the Fastogen Blue 8120 series. Products include materials for printers and material for plate making. X-form metal-free phthalocyanine is less sensitive than titanyl phthalocyanine, but is considerably lower in price. The prices are only 2000 to 5000 a kilogram. Figure 17.6 shows a comparison of the transient decay curve of surface potential of single layer photoreceptors with the X-form metal-free phthalocyanine and the Y-form titanyl phthalocyanine. The... 

Hammond, R. B., Roberts, K. J., Docherty, R., Edmondson, M., and Gaims, R., X-form metal free phthalocyanine Crystal structure determination using a combination of high resolution X-ray powder diffraction and molecular modelling techniques, J. Chem. Soc. Perkin Trans., 2, 1527, 1996. 

The X-ray measurements of Robertson and his co-workers were in all cases carried out on the more stable /3 modification, which is also the more crystalline modification. The a modification is unstable to transition to the 8 form in aromatic solvents (335). Ebert and Gottlieb have published (81) detailed methods by which the different polymorphs of copper, nickel, zinc, and metal-free phthalocyanine may be isolated. Phthalonitrile condenses in hydrogen-donor solvents, such as cyclohexylamine, to form metal-free phthalocyanine. The a metal-free phthalocyanine may be obtained from this reaction by milling the product in the dry with sodium chloride, the 6 form by milling in the presence of xylene. Solutions of metal-free phthalocyanine in sulfuric acid precipitate the a modification upon dilution (172). This may be sublimed below 200°C in vacuo, but is converted to the j8 modification above this temperature. Copper phthalocyanine behaves similarly. The 6 phthalocyanine may be reconverted to the a form by milling in the dry with sodium chloride or sodium sulfate. The y metal-... 

Metal-free phthalocyanine has been prepared in several forms a (tetragonal), P (monoclinic), x (hexagonal), and x. Figure 7 shows the interconversions. For example, treatment of Monolite Fast Blue GS (ICI) with hot dimethylformamide followed by ball milling in isopropyl alcohol yields the fi-form as needles, whereas acid pasting produces the a-form as needles and flakes (Loutfy, 1981). Milling under different conditions yields either the x-form as needles or flakes (Takano et al., 1984 Kakuta et al., 1985) or the x-form as needles (Sharp and Lardon, 1968 Hackett, 1971). The x-form as rods has been... 

Metal-free phthalocyanine (H2PC) exists in the a, P, r, and X polymorphic forms. The a,P, and X forms have been characterized by electrochemistry [36a], fluorescence spectroscopy [36b], and optical absorption [36c] and a,p, and t forms by C-NMR spectroscopy [36d], optical absorption, and X-ray powder diffraction [36e]. Figure 19 shows the optical absorption spectra of the four forms. The t form has been further characterized as to particle shape (Types I and II) [36f]. The as-synthesized y9-H2Pc is converted to a-H2Pc by acid pasting and this can be converted to the X or T forms with mechanical milling under specific conditions. The X and r forms convert to the P with thermal, solvent, or extended mechanical treatment. 

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