**4. Conclusions**

The one-dimensional solid state structures of (**1**) and (**2**) are held together by weak interactions via bridging anions—chlorides and azides, respectively—which are disrupted in solution. Because of the polymeric nature and low symmetry of these materials, the analysis of the magnetic properties has been supported by DFT calculations, suggesting strong antiferromagnetic exchange within Cu3 units and weak ferromagnetic interactions among these units. The predominant antiferromagnetic exchange within the Cu3 units has been unequivocally determined in both cases by the analysis of magnetic susceptibility characteristics. In addition, the operation of an antisymmetric exchange in (**1**) was evident by both magnetometry and EPR spectroscopy. The much weaker inter-Cu3 exchange, ferromagnetic in (**1**) and antiferromagnetic in (**2**), is attributed to the fact that non-magnetic Cu-orbitals are involved at one or both ends. EPR spectroscopy determined the magnitude of dipolar interaction in solid state (**1**), while the possible dipolar interaction between Cu3-units of (**2**) cannot be determined with certainty. The solution EPR spectra of both compounds are clearly distinguished from those in the solid state and are straightforwardly attributed to individual Cu3(<sup>μ</sup>3-OH) species of (**2**), and to the presence of isolated mononuclear and trinuclear species in the case of (**1**). Two new reports, describing the magnetic susceptibilities and (in one case) the EPR spectrum of polymeric supramolecular assemblies of copper(II) complexes, appeared in the literature recently [61,62].

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2624-8549/2/3/39/s1. Table S1: Crystallographic and refinement data for (**1**) and (**2**). Table S2: Selected interatomic distances (Å) and angles (◦) for (**1**). Table S3: Selected interatomic distances (Å) and angles (◦) for (**2**) Figure S1: ORTEP diagram of (**1**). Figure S2: ORTEP diagram of (**2**). Figure S3: Infrared spectrum of (**2**). Figure S4: Solid-state X-band EPR spectra of (**1**) between 5 and 295 K. Figure S5: Dipolar exchange scheme indicating the symmetry codes of the spins Si (i = 1–4) and the main intermolecular distances of (**1**). The crystallographic data for this paper (CCDC 2005300 and 2005301) can also be obtained free of charge via www.ccdc.cam.ac.uk/data\_request/cif, by emailing data\_request@ccdc.cam.ac.uk, or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44 1223 336033.

**Author Contributions:** Conceptualization, R.G.R.; formal analysis, L.M., R.H. and A.K.B.; investigation, K.S., L.M., R.H. and A.K.B.; writing—original draft preparation, K.S., L.M., R.H. and A.K.B.; writing—review and editing, L.M., R.H., A.K.B. and R.G.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** Research at FIU was funded partially by the National Science Foundation, gran<sup>t</sup> number CHE-1213683. R.H. acknowledges the financial support from institutional sources of the Department of Inorganic Chemistry, Palacky University in Olomouc, Czech Republic, and from the National Programme of Sustainability I (LO1305) of the Ministry of Education, Youth and Sports of the Czech Republic.

**Acknowledgments:** We thank Philippe Turek for support throughout this study.

**Conflicts of Interest:** The authors declare no conflict of interest.
