Microwave-assisted synthesis and sublimation enthalpies of hemiporphyrazines

Abstract

It was established that microwave irradiation solvent-free processing of 2,6- diaminopyridine or 1,3-phenylenediamine with phthalonitrile or 4-tert-butylphthalonitrile led to corresponding hemiporphyrazines with sufficiently high yields and a huge reduction in the time required for synthesis, from 8–12 h to 20 min. The data of IR and UV-vis spectroscopies and elemental analysis of the final products were found to be similar to those described in literature. The obtained hemiporphyrazines were characterized by 1H and [Formula: see text]C NMR data. We applied the Knudsen effusion method with mass spectrometric control of vapor composition. The mass spectrometric investigations established that the macrocyclic compounds give a stable stream of particles and their enthalpies of sublimation were estimated by the second law of thermodynamics.