Interaction of Electron Accepting Vapors with Phthalocyanines and Related-Compounds - aNovel Calorimetric Study

An interferometric fibre-optic calorimeter capable of measuring heats of interaction between electron acceptor dopants and thin films of a wide range of materials with mu-J sensitivity has been developed and used to measure heats of interaction of NO2 (typically at a pressure of 3.5 mbar) with copper and lead phthalocyanine (Cupc and Pbpc) films. For Cupc these heats are consistent with weak chemisorption, which occurs significantly faster than the associated increase in electrical conductivity. For Pbpc oxidative ring cleavage with partial nitration occurs, with heat release typically in excess of 800 kJ mol-1, after variable time intervals.