Phthalocyanine cell constants

An X-ray diffraction study of powdered a copper phthalocyanine, prepared by diluting a concentrated sulfuric acid solution of 8 copper phthalocyanine, has been made (305). The space group is probably P4/m (C 4h), containing six molecules per unit cell. The cell constants, a = 17.376 A and b = 12.790 A, were determined. The heat of transition of a to 8 copper phthalocyanine in o-chlorophenol at 80°C is 2.57 0.03 kcal/ mole (2.9). 

Lan and Mottola [14] have presented two continuous-flow-sensing strategies for the determination of C02 in gas mixtures using a special reaction cell. Both approaches are based on the effect of the complex of Co(II) with phthalocyanine as a rate modifier of the CL emission generated by luminol in the absence of an added oxidant agent, which is enhanced by the presence of C02 in the system. This enhancement allows the fast and simple determination of carbon dioxide at ppm levels (v/v) in atmospheric air and in human breath. In the first case, a continuous monitoring system was applied however, because the flow of expired gas is not constant, a discrete sample introduction approach was used in the analysis of C02 in breath. 

The surface structures observed for the multilayer phthalocyanine films are summarized in Table 5.7. These structures do not correspond to planes of either of the previously reported crystal structures of vapor deposited phthalocyanine films since the unit mesh constants reported in this work are considerably smaller than those previously reported. The unit cell dimensions correspond much more closely to a unit cell containing one molecule rather than, for example, the four molecules per cell reported for a-phthalocyanine. 

The molecules are filled into Knudsen- or Langmuir-type evaporation cells and heated up to their sublimation temperature. Mass spectra show that the materials are usually clean and sublime without destruction, even above the temperature at which the maximum evaporation rate is obtained. The sublimation condition remains constant and reproducible in contrast to many other stable organic materials like phthalocyanines. Usually no residuents remain in the cell. This shows the excellent processability of oligothiophenes for thin film formation from the gas phase. Typical evaporation conditions will be summarized in Tables 13.1 and 13.2 for a5T and a6T, respectively. 

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