## 2 Results and Discussion
### Structural Aspects
It should be highlighted that the structures of **III** and **IV** are unusual, with only one bridging \(\mu_{2}\)-coordinated chloride ligand linking two neighboring Cu(II) atoms in a polymeric chain, because incorporation of chlorine into the coordination sphere of a transition metal in the triazole chains is known to result in triple bridges containing two \(\mu_{2}\)-coordinated chloride ligands [4]. The latter situation is encountered in the crystal structure of [Cu(Htrz)Cl\({}_{2}\)] (Htrz = 4_H_-1,2,4-triazole) [26], which was the first one for a triazole complex elucidated by single crystal X-ray analysis, and in the related chain of [Cu(\(\mu_{2}\)-NH\({}_{2}\)trz)(\(\mu_{2}\)-Cl)\({}_{2}\)] [10]. Thus, depending on the synthesis conditions, it is possible to obtain one or two \(\mu_{2}\)-coordinated chloride ligands in the triple bridge, giving rise to charged or neutral chains, respectively. The Cu-N bond lengths in **III** and **IV** are similar to those found in the crystal structures of **I** and **II**, being about 2.0 A (Tables S4 and S5 in Supplementary Information). The Cu-Cl bond lengths in **III** are about 2.69-2.78 A (Table S4 in Supplementary Information), while the same bond lengths in **IV** are slightly shortened, about 2.65-2.72 A (Table S5 in Supplementary Information). Thus, the equatorial positions on the octahedron are occupied by nitrogen atoms, while the chlorine atoms are in apical positions. Each coordinated Cl\({}^{-}\) anion exhibits a bridging \(\mu_{2}\)-coordination mode, while NH\({}_{2}\)trz ligands exhibit a bridging bis-monodentate \(\mu_{2}\)-\(N_{1}\),\(N_{2}\)-coordination mode, linking two neighboring Cu(II) atoms (Figure 2). The N-Cu-N bond angles in each coordination octahedron of **III** and **IV**, formed by nitrogen atoms of the NH\({}_{2}\)trz ligands coordinated in a _cis_-arrangement, are similar to those observed for **I** and **II** and are about 90\({}^{\circ}\). The N-Cu-N bond angles formed by the nitrogen atoms in _trans_-position are significantly enlarged, 178-180\({}^{\circ}\) (Tables S4 and S5 in Supplementary Information). The N-Cu-Cl bond angles are in the range 85-95\({}^{\circ}\) both in **III** and **IV** (Tables S4 and S5 in Supplementary Information). The Cl-Cu-Cl bond angles are almost straight, 178-180\({}^{\circ}\). The Cu-N-N bond angles defined by the Cu(II) atoms with NH\({}_{2}\)trz ligands are 122-124\({}^{\circ}\), while the Cu-Cl-Cu bond angles are about 84\({}^{\circ}\) in both polymeric complexes (Tables S4 and S5 in Supplementary Information). The Cu(II) atoms are located almost in the same plane with the triazole rings. There are two distinguishable octahedron orientations along the polymeric chains resulting in alternate _ababa_... order. Depending on the presence of intrachain ligand interactions, both _ababa_... [18,21,22] and _abcbab_... [27] order may be found in Cu(II) chains with triple \(\mu_{2}\)-\(N_{1}\),\(N_{2}\)-triazole bridges. In complexes, **III** and **IV**, the lack of direct intrachain ligand-\(\cdots\)ligand interactions, leads to the more regular _ababa_... order. It should be noted, that the angles between the planes formed by the triazole fragments coordinated to two Cu(II) atoms within a chain in **III** and **IV** are 74.23(13) and 66.55(12)\({}^{\circ}\), respectively. This is considerably higher compared to Cu(II) \(\mu_{2}\)-\(N_{1}\),\(N_{2}\)-1,2,4-triazole chain complexes (e.g., 50.9(2)\({}^{\circ}\) for [Cu(\(\mu_{2}\)-NH\({}_{2}\)trz)\({}_{3}\)]ZrF\({}_{6}\) H\({}_{2}\)O [21]). The supramolecular aggregation in the structure of **II** consists of head-to-tail double sheets of mononuclear building units (Figure 4). Counter anions are located between double sheets, which are linked by a dense hydrogen bonding network involving amino groups of NH\({}_{2}\)trz and the PF\({}_{6}\)\({}^{-}\) anions (Table S2 in Supplementary Information). Each amine group is hydrogen bonded to two counter anions and one neighboring amine group.