5 7 much more reactive toward dicyanoketene formation as indicated by onset of the reaction below 100" C. No ketene signals were seen from 1 until 300" C was attained. This was consistent with the difference in fragmentation of the molecular ions of 1 and 2 (vide supra). As the oven temperature was raised, new reaction pathways became available which were different for 1 and 2. In the case of 2, the signals from dicyanoketene dropped ...
