PXRD Measurements. Crystallographic identifications were accomplished by X-ray diffraction (XRD) method on a benchtop Rigaku Miniflex diffractometer with a Cu-Kα radiation source operated at 30 kV and 10 mA. The acquisition angle ranged from 10 o to 90 o . DSC Mesurements. DSC measurements were performed on a Perkin Elmer Diamond DSC 4000 with a heating rate of 10 K•min -1 under nitrogen flow of 20 mL•min -1 .