*4.4. Hirshfeld Surface Study*

Hirshfeld surfaces and their respective 2D fingerprint plots for all complexes were calculated with CRYSTALEXPLORER 3.1 software [39]. The *d*norm surface and the breakdown of two-dimensional fingerprint plots were used to analyze intermolecular interactions in the di fferent crystal lattices. The sizes and shapes of the fingerprints illustrate the significant di fferences between the intermolecular interaction patterns.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2624-8549/2/1/5/s1, Figure S1: Infrared Spectra, Figure S2: Thermogravimetric analysis, Figure S3: Powder X-Ray Di ffraction patterns, Table S1: Crystal data and structure refinement. CCDC 1971817-1971820 contains the supplementary crystallographic data for **1**, **1.solv**, **2** and **3**.

**Author Contributions:** Conceptualization, R.C. and A.B.L.; methodology, R.C. and O.G.-P.; synthesis, characterization, thermal analysis, O.G.-P.; formal analysis, R.C. and O.G.-P.; investigation, O.G.-P.; resources, R.C. and O.G.-P.; writing—original draft preparation, R.C. and A.B.L.; writing—review and editing, R.C., A.B.L. and E.M.V.-L.; visualization, R.C. and A.B.L.; supervision, E.M.V.-L.; project administration, R.C. and E.M.V.-L.; funding acquisition, R.C. and E.M.V.-L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by ERDF (EU), MEC (Spain) and Xunta de Galicia (Spain) (research projects CTQ2015-71211-REDT, CTQ2015-7091-R and ED431D 2017/01).

**Acknowledgments:** SC-XDR measurements were performed at the Unidade de Difracción de Raios X de Monocristal (CACTI-Universidade de Vigo), Spain. O.G.P. thanks the Xunta de Galicia for a predoctoral contract.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
