1,3-Dipolar Cycloaddition Reactions of 1-Methyl-3-Oxidopyridinium Betaine with C70-A Theoretical Study

In the present study, the molecular orbital properties of 1,3-dipolar cycloaddition products of 1-methyl-3-oxidopyridinium betaine with C-70 have been investigated theoretically at the level of PM3 (RHF) type semi empirical quantum chemical calculations and then single point DFT calculations were performed for the energies. The betaine acts as a 4 pi-component across its 2,6-positions and certain C=C bonds of C-70 act as 2 pi-component in the 1,3-dipolar cycloadditions considered presently. Various cycloadducts are structurally possible because C-70 structure possesses 8 different 2 pi-components, therefore 8 different pairs of reaction termini exist. The results indicate that, the cycloadducts (including regioisomers) formed with [6, 6]-type double bond are more stable and less endothermic than adducts formed with the [5, 6]-type with some exceptions. Some structural, spectral and physicochemical properties of these cycloadducts have also been studied.