Syntheses, crystal structures and spectroscopic properties of two Cu2+-doped single crystals containing 3,14-diethyl-2,6,13,17-tetraazatricyclo[16.4.0.07,12]docosane

Abstract In this study, two Cu2+-doped single crystals, [Cu0.02(H1.96L)](ClO4)2 (1) and [Cu0.91(H0.18L)](ClO4)2 (2) (L = 3,14-diethyl-2,6,13,17-tetraazatricyclo(16.4.0.07,12)docosane), were prepared and characterized by elemental and X-ray crystal structural analyses, along with UV–visible, infrared (IR) and electron paramagnetic resonance (EPR) spectroscopies. The asymmetric units of compounds 1 and 2 contain one half of the molecular dication and one doubly disordered perchlorate anion. The macrocyclic ligand in both the Cu2+-doped compounds adopts the most stable trans-III conformation. The Cu–N bond lengths in the range 2.010 (2)–2.055 (3) A are normal, but the long axial Cu1–O3 bonds of 2.836 (3) and 2.729 (3) A for 1 and 2, respectively, may be due to a combination of the Jahn-Teller effect and strong in-plane ligand field. The crystals are stabilized by hydrogen bonds involving the secondary N–H, the N atoms of the macrocycle, and the O atoms of the perchlorate groups.