XRD patterns of solid samples were measured using an X-ray diffractometer with Cu Kα radiation injected at a split ratio of 1:10, and flowed into a column (DB-Sulfur SCD column, Agilent) with He (purity > 99.99995%) at a constant rate of 2.8 mL min -1 . The column temperature was initially maintained at 35 °C for 3.5 min, and thereafter, raised to 245 °C at a rate of 20 °C min -1 . The positivemode electrospray ionization (ESI) was applied, and the scan range was set to m/z 20-100 Da.