Thermal stability of a fullerene-amine adduct

A fullerene-diethylamine adduct has been prepared by an addition reaction a t room temperature and is characterized by FTIR, UV-VIS Spectroscopy, X-Ray Diffraction and HPLC techniques. After repeated recrystallisation from hex ane the purified adduct has been studied by Thermogravimetry and Differenti al Scanning Calorimetry. Thermal Analysis and associated characterisation s tudies indicate that on heating the adduct undergoes an elimination reactio n, i.e., the secondary amine which adds on to C-60 at room temperature is e liminated between 100 and 650 degrees C. This leads to the formation of the retro product C-60 which has been characterized by spectroscopic studies o n quenched samples. Kinetics studies indicate that in contrast to the addit ion reaction which is fast (almost instantaneous) the elimination reaction is sluggish and the process is associated with an activation energy of only 12-13 kJ mol(-1). Possible reasons for this unusual kinetic behaviour are suggested. (C) 2000 Elsevier Science B.V. All rights reserved.