Effect of Substituent Position on Saturated Vapor Pressure of Tetrafluorosubstituted Zinc Phthalocyanines

This work is devoted to the study of the effect of the position of fluorine substituents in the molecules of tetrafluorosubstituted zinc phthalocyanines on their saturated vapor pressure. For this purpose, the temperature dependence of the saturated vapor pressure of zinc phthalocyanines with fluorine substituents in the peripheral (ZnPcF 4 -p) and non-peripheral (ZnPcF 4 -np) positions of the phthalocyanine ring has been studied by the Knudsen method with mass spectrometric recording of the composition of the gas phase and the thermodynamic parameters of vaporization were calculated. The data obtained for ZnPcF 4 -p and ZnPcF 4 -np with unsubstituted and hexadecafluorosubstituted zinc phthalocyanines are compared in terms of analysis of intermolecular interactions in the crystals of these compounds. It has been shown that tetrafluorosubstituted phthalocyanines have a higher vapor pressure than their unsubstituted (ZnPc) and hexadecafluorosubstituted (ZnPcF 16 ) derivatives. In this case, the enthalpy of sublimation increases in the series ZnPcF 4 -p < ZnPcF 4 -np < ZnPc < ZnPcF 16 .