*4.3. X-ray Structure Determination*

Crystallographic data were collected at 293 K on a Bruker Smart 1000 CCD diffractometer using graphite-monochromated Mo-Kα radiation (λ = 0.71073 Å). The software SMART [32] was used to collect frames of data, index reflections, and determine lattice parameters. SAINT [33] was used for integration of intensity of reflections and SADABS [34] for scaling and empirical absorption correction. The structure was solved by a dual-space algorithm using the program SHELXT [35]. All non-hydrogen atoms were refined with anisotropic thermal parameters by full-matrix least-squares calculations on F2 using the program SHELXL [35] with OLEX2 [36]. Hydrogen atoms were inserted at calculated positions and constrained with isotropic thermal parameters. Drawings were produced with Mercury [28]. Special computations for the crystal structure discussions were carried out with PLATON [37]. Crystal data and structure refinement parameters are reported in Table S1.

X-ray powder di ffraction (XRPD) was performed using a Siemens D-5000 di ffractometer with Cu-K α radiation (λ = 1.5418 Å) over the range 5.0−60.0◦ in steps of 0.20◦ (2θ) with a count time per step of 5.0 s. The program FULLPROF [38] was used to perform profile matching between powder di ffraction data and that calculated from the single-crystal structures.
