Thermal analysis and theoretical study of α-cyclodextrin azomethine [2]-rotaxane formation by semi-empirical method PM3

M/α-CD azomethine [2]-rotaxane composed of a triazole/α-cyclodextrin (α-CD) inclusion complex and bulky pyrene groups linked together through azomethine bonds has been studied by thermal analysis and quantum semi-empirical method PM3. The comparison of the monomer rotaxane and non-rotaxane structures reveals that [2]-rotaxane formation is sufficient to increase the thermal stability of the non-rotaxane M monomer, as well as favorable solubility characteristics. Semi-empirical calculations confirmed that α-CD macrocycles are sufficiently large to thread onto the triazole rings, while the pyrene moieties are sufficiently large to serve as stoppers in the resulting [2]-rotaxane.