Unique Bridging Function of the Triazole Core in Copper(II) Chloride Complexes with 1‐Allylbenzotriazole

During alternating‐current electrochemical synthesis of copper(I) π‐complex of [CuCl{C 6 H 4 N 3 (C 3 H 5 )}] composition, starting from ethanol solution, containing CuCl 2 ·2H 2 O and 1‐allylbenzotriazole, green crystals of intermediate [Cu II 3 Cl 6 {C 6 H 4 N 3 (C 3 H 5 )} 4 ] ( I ) compound has been obtained upon 24 h. After some days these crystals transform into red ones of [Cu II 2 Cl 4 {C 6 H 4 N 3 (C 3 H 5 )} 3 ] ( II ). Both compounds were X‐Ray structurally investigated. Crystals of I are triclinic, sp.gr. ${\rm P}{\bar 1}$ a = 9.1329(9), b = 10.0352(4), c = 12.239(3) Å, α = 76.443(13), β = 84.470(14), γ = 76.808(7)°, V = 1060.5(3) Å 3 , R = 0.0414 for 3311 reflections. II : monoclinic, C2/c, a = 13.828(1), b = 15.044(2), c = 10.702(1) Å, β = 91.36(1)°, V = 2225.7(4) Å 3 , R = 0.050 for 1495 reflections. In both compounds each benzotriazole core coordinates two copper atoms using two nitrogen atoms in 2 and 3 positions. Isolated Cu 3 Cl 6 fragments in I are condensed along [001] direction into infinite chains [CuCl 2 ] n in II. Finally, red crystals of II transform into colorless ones of the earlier studied copper(I) π‐complex of CuCl·C 6 H 4 N 3 (C 3 H 5 ) composition.