Synthesis and thermogravimetric analysis of inclusion complexes of O2N2-donor Aza-crown macrocyclic ligands with [60]fullerene

A simple method for the formation of inclusion complex of [60]fullerene with two O₂N₂-donor aza-crown macrocyclic ligands was introduced. The products were characterized using UV–vis and IR spectroscopies as well as HPLC, and ESI mass spectrometry. The ESI mass and elemental analysis data revealed that the ratio of macroring:[60]fullerene were not the same. The binding capability of the macrorings as well as the number of the macroring addends to [60]fullerene were investigated using thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). Considering percentage mass loss in different steps of TG and the enthalpy changes in DSC found for each of these products, the number of their addends on [60]fullerene were calculated. Theoretical calculations in semi-empirical level using AM1 suggested that proper orientation of the nitrogen-donor groups on the aza-crown macrorings toward [60]fullerene could be the main factor for the observed difference in the number of macroring addends attached to [60]fullerene.