Melting point and enthalpy of fusion
Melting points and enthalpies of fusion of samples were obtained using a differential scanning calorimeter (DSC) model Q2000 (TA Instruments, Mississauga, ON, Canada). Nitrogen was used as the purge gas with a flow of 18 mL/minute. In this experiment, melting points (endothermic peak) of samples (2-5 mg) were determined by heating samples from 5 °C to 60 °C at the heating rate of 5 °C/minute.