*3.4. X-ray Measurements*

A crystal of **1** was immersed in cryo-oil, mounted in a Nylon loop, and measured at 150 K. Intensity data were collected using a Bruker AXS-KAPPA APEX II diffractometer (Bruker AXS Inc., Madison, WI, USA) with graphite monochromated Mo-Kα (λ 0.71073) radiation. Omega scans of 0.5◦ per frame were used for data collection and a full sphere of data was obtained. Cell parameters were retrieved using Bruker SMART [63] software and the data were refined using Bruker SAINT [63] on all the observed reflections. SADABS was used for absorption corrections [64]. Direct methods were employed by using SHELXS97 [65] and refined with SHELXL2018/3 [66]. Calculations were conducted using WinGX version 2018.3 [67]. The H-atoms bonded to carbon and nitrogen were introduced in the model at geometrically calculated positions and refined using a riding model, with Uiso defined as 1.2Ueq of the parent carbon atoms for aromatic residues and for nitrogen, and 1.5Ueq for the methyl group. The hydrogen atoms of water ligands were found in the difference Fourier map and allowed to refine with distance restrains. The non-coordinated water molecule was disordered over two positions and refined with the use of PART instruction, with the occupancy of O1W and O2W at a ratio of 74% and 26%, respectively. After this strategy, the remaining electron density was considered as being due to another water molecule (O3W), which was refined with an occupancy of 0.25, flanked by PART -1, and the structure finalized normally. The hydrogen atoms of O1W, O2W, and O3W could be neither located nor inserted in the calculated positions (the use of the CALC-OH routine in WinGX proved to be unsuccessful). Least square refinements were carried out with anisotropic thermal motion parameters for all of the non-hydrogen atoms.
