PHOTOLYSIS AND THERMOLYSIS OF DIARYL(PENTAZADIENE) COMPOUNDS IN SOLID-MATRIX INVESTIGATED BY INFRARED-SPECTROSCOPY

The photochemically and thermally induced decay of four 1,5-diaryl-3-m ethyl-pentazadiene compounds in KBr matrix is investigated by infrared spectroscopy. The decomposition proceeds under the release of nitroge n and leads to substituted aromatic compounds. No intermediates are de tected in photolytic experiments in solid, which is in contrast to for mer experiments in solution. We show that thermolysis proceeds via a r eversible step. Particularly in the case of compound II, there is sign ificant recovery of some peaks if a sample heated to a temperature sli ghtly below the decomposition point is subsequently cooled down to roo m temperature again. In the case of compound III, neither intermediate s nor condensed end products are observed, which indicates the generat ion of small volatile fragments. (C) 1998 Elsevier Science S.A.