*2.2. Crystal Structure Determinations*

Single crystal X-ray analyses were undertaken on crystals transferred directly from the mother liquor to a protective oil before being mounted on the di ffractometer in a stream of cooled N2 gas. All data were collected on a Rigaku Oxford Di ffraction XtaLAB Synergy dual source di ffractometer. Data measurement and reduction was performed using CrysalisPro software [24]. The structure was solved using SHELXT [25] and refined using a full-matrix least squares method based on *F*<sup>2</sup> [26]. Crystallographic and refinement data are presented in Table 1. Twinning was apparent for compound **VI** and this resulted in elevated agreemen<sup>t</sup> values.


**Table 1.** Crystallographic and refinement data for compounds **III**–**VI**.
