## 3 Experimental Section
### Syntheses  
_N,N'_**-bis-(1,2,4-triazole-4-yl)formamidine hydrochloride (L**HCI)**: A solution of NH\({}_{2}\)trz (4.9 g, 58.3 mmol), HC(OEt)\({}_{3}\) (9.8 g, 66.1 mmol) and NaN\({}_{3}\) (3.9 g, 60 mmol) in AcOH (25 mL) was heated at 105 \({}^{\circ}\)C for 3 h. The reaction mixture was then cooled and 37% aqueous HCl (5.8 g, 58.3 mmol) was added. The resulting solution was filtered and concentrated under reduced pressure to give a yellowish solid, which was washed by hot EtOH (80 mL) to afford a white solid. Yield: 1.5 g (12%). mp \(>\) 200 \({}^{\circ}\)C. IR: \(v\) = 3105 (_m_), 3095 (_m_), 3068 (_m_), 3025 (_w_), 2971 (_vw_), 1657 (_s_), 1491 (_m_), 1447 (_w_), 1393 (_m_), 1362 (_w_), 1318 (_m_), 1285 (_m_), 1264 (_m_), 1173 (_m_), 1055 (_s_), 990 (_m_), 959 (_m_), 947 (_m_), 899 (_w_), 872 (_m_), 833 (_m_), 764 (_m_), 614 (_s_), 532 (_w_) cm\({}^{-1}\). \({}^{1}\)H NMR: \(\delta\) = 8.65 (s, 1H, CH), 8.83 (s, 4H, CH, 1,2,4-triazole) ppm. Anal. Calc. for C\({}_{5}\)H\({}_{7}\)ClN\({}_{8}\) (214.62): C 27.98, H 3.29, N 52.21. Found: C 27.63, H 2.99, N 51.11. Crystals of **L** suitable for a single crystal X-ray analysis were obtained by dissolving 0.2 g of **L**\(\cdot\)**HCl** in H\({}_{2}\)O-acetone (5 mL; 50:50, _v/v_) solution, which was slowly evaporated at room temperature affording single crystal on standing (4 days). **[Cu(NH\({}_{2}\)trz)\({}_{4}\)(H\({}_{2}\)O)](AsF\({}_{6}\))\({}_{2}\) (I)**: A solution of NH\({}_{2}\)trz (0.252 g, 3 mmol) in MeOH (10 mL) was added drop wise to a solution of [Cu(H\({}_{2}\)O)\({}_{6}\)](AsF\({}_{6}\))\({}_{2}\) (0.550 g, 1 mmol) in MeOH (5 mL). The resulting blue precipitate was filtered off, washed with MeOH and dried in a desiccator. A small amount of a solid material (0.050 g) was dissolved in water (100 mL). Crystals suitable for a single crystal X-ray analysis were obtained on standing (12 months) with slow evaporation of the solvent. Yield: 0.376 g (63%). Anal. Calc. for C\({}_{8}\)H\({}_{18}\)As\({}_{2}\)CuF\({}_{12}\)N\({}_{16}\)O (795.71): C 12.08, H 2.28, N 28.16. Found: C 12.17, H 2.23, N 28.24. **[Cu(NH\({}_{2}\)trz)\({}_{4}\)(H\({}_{2}\)O)](PF\({}_{6}\))\({}_{2}\) (II)**: **L**\(\cdot\)**HCl** (0.300 g, 1.39 mmol) was dissolved in water (10 mL). Then a solution of KPF\({}_{6}\) (0.208 g, 1.13 mmol) and CuCl\({}_{2}\cdot\)2H\({}_{2}\)O (0.097 g, 0.57 mmol) in water (10 mL) was added dropwise leading to a precipitate. To the resulting mixture, additional water (500 mL) was added and the solution was heated until the precipitate completely dissolved. Crystals suitable for a single crystal X-ray analysis were obtained on standing (8 months) with slow evaporation of the solvent and slow delivery of NH\({}_{2}\)trz by hydrolysis of **L**. Yield: 0.285 g (74%). Anal. Calc. for C\({}_{8}\)H\({}_{18}\)CuF\({}_{12}\)N\({}_{16}\)OP\({}_{2}\) (707.8): C 13.57, H 2.56, N 31.64. Found: C 14.37, H 2.52, N 33.30. **[Cu(\({}_{2}\)-NH\({}_{2}\)trz)\({}_{2}\)Cl]Cl\(\cdot\)H\({}_{2}\)O (III)**: Path A: A solution of Cu(CH\({}_{3}\)COO)\({}_{2}\cdot\)H\({}_{2}\)O (0.106 g, 0.053 mmol) in water (5 mL) was added to a solution of (NH\({}_{4}\))\({}_{2}\)CuCl\({}_{4}\cdot\)2H\({}_{2}\)O (0.147 g, 0.053 mmol) in the same solvent (5 mL). The resulting blue solution was added to a solution of NH\({}_{2}\)trz (0.134 g, 0.159 mmol) in MeOH (5 mL). Then the mixture was cooled in ice till the blue solid was precipitated. The obtained solid material was filtered off and dissolved in water (50 mL) upon heating. Crystals suitable for a single crystal X-ray analysis were obtained on standing (several weeks) after slow evaporation of the solvent. Yield: 0.114 g. Path B: **L**\(\cdot\)**HCl** (0.300 g, 1.39 mmol) was dissolved in water (10 mL). Then a solution of CuCl\({}_{2}\cdot\)2H\({}_{2}\)O (0.097 g, 0.57 mmol) in water (10 mL) was added dropwise leading to the formation of a precipitate. To the resulting mixture, additional water (450 mL) was added and the solution was heated until the precipitate completely dissolved.